Broad spectrum neutralizing antibodies against influenza neuraminidase

Abstract

The present disclosure provides antibodies and antigen-binding fragments thereof that bind to influenza virus neuraminidase (NA) and that neutralize influenza virus infection. Also provided are polynucleotides encoding the antibodies, vectors comprising such polynucleotides, host cells that can express the antibodies, related compositions, and methods of using the compositions disclosed herein, for example, to treat or prevent influenza infection.

Description

[0001] Reference to an electronic sequence listing

[0002] The contents of the electronic sequence listing (930585_439WO_SEQUENCE_LISTING.xml; size: 136949 bytes; and creation date: May 17, 2023) are incorporated herein by reference in their entirety. Background Art

[0003] Influenza is an infectious disease that breaks out around the world each year, causing approximately three to five million cases of severe illness and approximately 290,000 to 650,000 deaths from respiratory illness each year (WHO, Influenza (Seasonal) Factsheet, November 6, 2018). The most common symptoms include: sudden onset of fever, cough (usually dry), headache, muscle and joint pain, severe malaise (feeling unwell), sore throat and runny nose. The incubation period varies between one and four days, but symptoms usually begin to appear about two days after exposure to the virus. Complications of influenza can include pneumonia, sinus infection, worsening of pre-existing health problems (such as asthma or heart failure), sepsis, or exacerbation of chronic underlying diseases.

[0004] Influenza is caused by influenza viruses, a group of antigenically and genetically diverse viruses belonging to the family Orthomyxoviridae that contain a negative-sense, single-stranded, segmented RNA genome. Of the four types of influenza viruses (A, B, C, and D), three types (A, B, and C) are known to affect humans. Influenza viruses can be classified based on the presence of different subtypes of major surface proteins: hemagglutinin (HA) and neuraminidase (NA). There are at least 18 influenza A subtypes defined by their hemagglutinin ("HA") proteins. HA can be classified into two groups. Group 1 includes subtypes H1, H2, H5, H6, H8, H9, H11, H12, H13, H16, and H17, and Group 2 includes subtypes H3, H4, H7, H10, H14, and H15. There are at least 11 different neuraminidase subtypes (N1 to N11, respectively (cdc.gov / flu / about / viruses / types.htm)). Neuraminidase plays a role in viral movement and dissemination by catalyzing the hydrolysis of sialic acid residues on proviral particles released from infected host cells and on glycoproteins on the surface of target cells. Drugs designed to inhibit neuraminidase (NAIs) have been developed (e.g., oseltamivir, zanamivir, peramivir, laninamivir), but naturally acquired mutations in IAV subtypes reduce susceptibility to current NAIs (Hussain et al., Infection and Drug Resistance 10:121-134 (2017)).

[0005] New approaches for treating influenza virus infections are needed. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 Figure 2 shows a workflow for anti-"NA" (neuraminidase) monoclonal antibody discovery. Donors were selected by screening the reactivity of serum from (human) tonsil donor samples (n=50) to neuraminidase subtypes N1 and N2 antigens, and the reactivity of serum from PBMC (peripheral blood mononuclear cells) donor samples (n=124) to neuraminidase subtypes N4, N3 and N9. Neuraminidase antigens for screening were expressed in mammalian cells and combined with flow cytometry assessment. B memory cells from five donors were sorted by flow cytometry to input into the discovery workflow. Single sorted B cells (n=39,350) were co-cultured with mesenchymal stromal cells (MSC) in 50 μl cultures to stimulate antibody secretion. Secreted antibodies were assessed by binding and NA inhibition assays. Inhibition of N1 sialidase activity was assessed using ELLA (enzyme-linked lectin assay), and inhibition of N1, N2, and N9 sialidase activity was measured using a fluorescence-based assay that measures the cleavage of 2'-(4-methylumbelliferyl)-α-DN-acetylneuraminic acid (MUNANA). "N1 activity" refers to neuraminidase inhibitory activity. Binding to NA from Group 1 IAV N1 A / Vietnam / 1203 / 2004 and Group 2 IAV N2 A / Tanzania / 205 / 2010 and N9 A / Hong Kong, China / 56 / 2015 was assessed by ELISA to determine breadth. Antibody sequences from selected B cells were cloned as cDNA and sequenced.

[0007] Figure 2A Shown is a sequence alignment of the VH domains of monoclonal antibodies (prefixed with "FNI") directed against influenza A virus ("IAV") isolated from human donor PBMCs. Figure 2B Shown is an alignment of the VH domain sequences of "FNI3" and "FNI9" (FNI9 comprises the following VH and VL amino acid sequences: VH: SEQ ID NO.: 2; VL: SEQ ID NO.: 8) with the unmutated common ancestor "UCA" (VH: SEQ ID NO.: 98; VL: SEQ ID NO.: 100).

[0008] Figures 3A to 3C The expression of FNI3 and FNI9 in the presence of N1 ( Figure 3A )、N2( Figure 3B ) and N9( Figure 3C)NA binding, which is reported as OD versus concentration in ng / ml. Binding of comparator antibody 1G01-LS and negative control antibody "K-" directed against an irrelevant antigen was also measured.

[0009] Figures 4A to 4C The results of biolayer interferometry (BLI) analysis of FNI3 carrying the M428L / N434S Fc mutation ("FNI3-LS") and FNI9 carrying the M428L / N434SFc mutation ("FNI9-LS") compared with N1 ( Figure 4A )、N2( Figure 4B ) and N9( Figure 4C )NA binding kinetics. Dissociation is reported as kdis (1 / s), association is reported as kon (1 / Ms), and KD is calculated based on the ratio of kdis / kon. Binding of the comparator antibody 1G01-LS was also measured.

[0010] Figure 5 Summarizes the results of flow cytometry assays testing FNI3 and FNI9 and comparator antibody 1G01 against a panel of Group I IAV, Group II IAV, and influenza B virus (IBV) NA binding. Bold indicates NA from influenza viruses isolated from humans. The values ​​on the right scale show the range of calculated EC50s. Values ​​were selected based on the lowest concentration at which binding was observed.

[0011] Figures 6A to 6C The activities of FNI3 and FNI9 towards NA carrying glycosylation sites are implicated. Figure 6A Glycosylation sites at positions 245 (245Gly+) and 247 (247Gly+) of group 2 IAV N2 subtype NA in A / South Australia / 34 / 2019, A / Switzerland / 8060 / 2017, A / Singapore / INFIMH-16-0019 / 2016, and A / Switzerland / 9715293 / 2013 are shown. Figure 6B Sialidase activity inhibition (NAI) of live virus stocks of A / Switzerland / 8060 / 2017, A / Singapore / INFIMH-16-0019 / 2016, and A / Switzerland / 9715293 / 2013 is summarized and reported as EC50 in μg / ml. Figure 6C Figure 2 shows the binding of FNI3 and FNI9 to NA in mammalian cells infected with A / South Australia / 34 / 2019 (245Gly+) measured by flow cytometry. Mock staining is shown as a negative control.

[0012] Figure 7Shown is the binding of FNI3 and FNI9 to NA expressed on mammalian cells infected with H1N1 porcine Eurasian avian (EA) strain A / swine / Jiangsu / Jiangsu / J004 / 2018 measured by flow cytometry. Mock staining is shown as a negative control.

[0013] Another experiment (data not shown) demonstrated the lack of polyreactivity of FNI3 and FNI9 binding to human epithelial type 2 (HEP-2) cells. Anti-HA antibody FI6v3 was used as a positive control, and anti-paramyxovirus antibody MPE8 was included as a negative control.

[0014] Figure 8 Summarized are the sialidase activity inhibition ("NAI") of FNI3 and FNI9 against a panel of Group IAV, Group II IAV, and influenza B virus (IBV) NAs as measured by the MUNANA assay.

[0015] Figure 9 Shown are in vitro inhibitions of sialidase activity of Group I (H1N1) IAV, Group II (H3N2) IAV, and IBV NA by FNI3 and FNI9 (reported as IC50 in μg / ml).

[0016] FIG. 10A to FIG. 10B Shown are in vitro inhibitions of sialidase activity of Group I (H1N1) IAV, Group II (H3N2) IAV, and IBV NA by FNI3 and FNI9 (reported as IC50 in μg / ml). Figure 10A Inhibitory activity against Group I IAV, Group II IAV, and IBV is depicted in the same graph, and Figure 10B Inhibitory activity against these IAVs is depicted in separate graphs.

[0017] Figure 11A Shown is a panel of IAV and IBV strains tested in an in vitro sialidase activity inhibition assay. Figure 11B Assay results for FNI3, FNI9, FNI14, FNI17, and FNI19 are shown (reported as IC50 in μg / ml). The asterisk in the legend indicates the presence of a glycosylation site in position 245.

[0018] 12A to 12D Antibodies FNI1, FNI3, FNI9, FNI14, FNI17, and FNI19 are shown to be resistant to H1N1 A / California / 07 / 2009 ( Figure 12A )、H3N2 A / Hong Kong, China / 8 / 68( Figure 12B )、B / Malaysia / 2506 / 2004( Figure 12C ) and B / Jiangsu / 10 / 2003( Figure 12D) neutralization of NA (reported as IC50 in μg / ml).

[0019] Figure 13A and Figure 13B FcγRIIIa ( Figure 13A ; F158 allele) and FcγRIIa ( Figure 13B ; H131 allele). Activation was measured using an NF AT-mediated luciferase reporter gene in engineered Jurkat cells. FNI3 and FNI9 were tested, along with comparator antibody FM08 ("FM08_LS" in the figure; VH: SEQ ID NO.: 25; VL: SEQ ID NO.: 26) and a negative control antibody (FY1-GRLR).

[0020] Figure 14A and Figure 14B Shown ( Figure 14A )N1(H1N1, swine H1N1 and avian H5N1) and ( Figure 14B )Annual frequency of NA antiviral resistance mutations in the N2 (H3N2, H2N2) subtype.

[0021] Figures 15A to 15E Neutralization of H1N1 A / California / 07 / 2009 viruses engineered with reverse genetics to carry oseltamivir-resistant (OSE) mutations (H275Y, E119D and H275Y, or S247N and H275Y) by anti-influenza antibodies or oseltamivir is shown. Figure 15A )、FNI9( Figure 15B ) and oseltamivir ( Figure 15C ) and comparator antibody FM08 ( Figure 15D ) and 1G01( Figure 15E ) neutralizing activity.

[0022] Figure 16A and Figure 16B Neutralization of group I (H1N1) IAV, group II (H3N2) IAV, IBV viruses, and IAV and IBV viruses engineered using reverse genetics to carry OSE-resistance mutations (H275Y, E119D / H275Y, H275Y / S247N, I222V, or N294S) by anti-NA antibodies is shown (reported as IC50 in μg / ml). Figure 16A Asterisks in the (x-axis) indicate viruses carrying OSE-resistant mutations. Neutralizing activity of FNI3, FNI9, and comparator antibody 1G01 was measured. Figure 16A Neutralization of individual virus strains is depicted, and Figure 16B Neutralization of virus strains grouped by neutralizing anti-NA antibodies is depicted.

[0023] Figure 17 Data from crystal structure studies showing the docking of the antigen-binding fragment (Fab) domain of the FNI3 antibody to NA are shown.

[0024] Figure 18A and Figure 18B The heavy chain complementarity determining region 3 (H-CDR3) from the FNI3 heavy chain is shown in its non-binding state with N2 NA ( Figure 18A ) or combined with ( Figure 18B Schematic diagram of the crystal structure study and construction of the unbound FNI3 H-CDR3 crystal structure ( Figure 18A ) shows the β-sheet conformation and the intact backbone hydrogen bonds between the carboxylic acid (CO) and amino (NH) groups of residues E111(CO)-D102(NH), E111(NH)-D102(CO), G109(CO)-F104(NH), G109(NH)-N105(CO), and L108(NH)-N105(CO). FNI3-N2 crystal structure ( Figure 18B ) shows the disruption of the H-CDR3 β-sheet conformation and one intact main-chain hydrogen bond between G109(CO)–F104(NH).

[0025] Figure 19A and Figure 19B Shown is a schematic diagram generated from crystal structure studies showing the docking angles of the antigen-binding fragment (Fab) domain of FNI3 and comparator antibodies 1G01, 1G04, and 1E01 in complex with NA subtypes. The lines indicate the docking angles in all panels, and the Protein Data Bank (PDB) identification codes of the comparator antibodies 1G01, 1G04, and 1E01 are shown. Figure 19A Shown are the complexes of 1G01 with N1 NA (upper panel) and 1G04 with N9 NA (lower panel). Figure 19B Shown are the complexes of FNI3 with N2 NA (upper panel) and 1E01 with N2 NA (lower panel).

[0026] Figure 20 Conformations and interactions of the FNI3 CDRs are shown: H-CDR3, H-CDR2 and L-CDR. To generate these data, proteins were "quickly prepared" using MOE (Molecular Operating Environment).

[0027] Figure 21The crystal structure of the complex of FNI3 and N2 NA is shown, including residues of the light chain CDRs (L-1, L-2, L-3) and heavy chain CDRs (H-1, H-2, H-3). The interaction between H-CDR3 and N2 NA is shown in the right figure with enhanced resolution. Negative numbers are interaction energies in kcal / mol. The protein was "quickly prepared" using MOE (Molecular Operating Environment) software.

[0028] Figure 22 A representation of the crystal structure of the complex of FNI3 and oseltamivir-bound N2 NA is shown. Oseltamivir is shown to interact with R292, R371, and R118 of N2 NA.

[0029] Figure 23 An alternative view of the crystal structure is shown, showing FNI3 in complex with oseltamivir-bound N2 NA.

[0030] Figure 24A and Figure 24B Shown is an analysis of FNI3 epitope conservation in N2 NA sequences from H3N2 isolated between 2000 and 2020 (n=60,597). Figure 24A The table in the figure shows the frequency of amino acids at specific positions in the analyzed N2 NA sequences. The circled values ​​indicate the three amino acids that occur with the lowest frequency: Glu221 (E221, 17.41%), Ser245 (S245, 33.69%), and Ser247 (S247, 36.16%). Acidic amino acids include aspartic acid and glutamic acid; basic amino acids include arginine, histidine, and lysine; hydrophobic amino acids include isoleucine, leucine, tryptophan, valine, alanine, and proline; neutral amino acids include asparagine and glutamine; and polar amino acids include serine, threonine, glycine, and tyrosine. Figure 24B Interactions of VH Y60 and Y94 from FNI3 with E221, S245 and S247 of N2 NA are shown.

[0031] Figure 25 N2 NA FNI3 epitope conservation is shown (top; as Figure 24A and Figure 24B Comparison of FNI3 epitope conservation (bottom) in N1 NA sequences of H1N1 (n=57,597) isolated between 2000 and 2020. Acidic amino acids include aspartic acid, glutamic acid; basic amino acids include arginine, histidine, lysine; hydrophobic amino acids include isoleucine, leucine, tryptophan, valine, alanine, proline; neutral amino acids include asparagine, glutamine; and polar amino acids include serine, threonine, glycine, tyrosine.

[0032] Figure 26A and Figure 26B Shown is the design of an in vivo study to evaluate FNI3 ( Figure 26A "mAb-03" in ) and FNI9 ( Figure 26A The protective activity of mAb-09 in Figure 3 was evaluated in BALB / c mice infected with IAV A / Puerto Rico / 8 / 34 or A / Hong Kong / 8 / 68. Figure 26A The doses and viral strains used in the studies are indicated. Figure 26B The timeline and endpoints of the study are shown.

[0033] 27A to 27D Figure 2 shows the weight measurements of BALB / c mice infected with H1N1 A / Puerto Rico / 8 / 34 over a fifteen-day period after pre-treatment with FNI9. One day before infection with the LD90 (90% lethal dose) of A / Puerto Rico / 8 / 34, 6 mg / kg ( Figure 27A )、2mg / kg( Figure 27B )、0.6mg / kg( Figure 27C ) or 0.2 mg / kg ( Figure 27D ) Antibodies were administered. Body weights of mice administered vehicle control were also measured (left graph in each figure).

[0034] 28A to 28D Figure 2 shows the weight measurements of BALB / c mice infected with H3N2 A / Hong Kong / 8 / 68 over 15 days after pre-treatment with FNI9. One day before infection with LD90 (90% lethal dose) of A / Hong Kong / 8 / 68, 6 mg / kg ( Figure 28A )、2mg / kg( Figure 28B )、0.6mg / kg( Figure 28C ) or 0.2mg / kg( Figure 28D ) Antibodies were administered. Body weights of mice receiving vehicle control were also measured (left graph in each figure).

[0035] Figure 29A and Figure 29B Shown are the results of treatment with FNI3 or FNI9 in A / Puerto Rico / 8 / 34 ( Figure 29A ) or A / China Hong Kong / 8 / 68( Figure 29B The survival rate of BALB / c mice pretreated with vehicle control was also measured.

[0036] Figure 30A and Figure 30B Shown are the results of pre-treatment with FNI3 or FNI9 in infected A / Puerto Rico / 8 / 34 ( Figure 30A ) or A / China Hong Kong / 8 / 68( Figure 30B The weight loss of BALB / c mice pretreated with 5% (v / v) nab was measured from day 4 to day 14 post infection (reported as area under the curve). The weight loss of mice pretreated with vehicle control was also measured.

[0037] Figure 31A and Figure 31B Shown are the results of treatment with FNI3 or FNI9 in A / Puerto Rico / 8 / 34 ( Figure 31A ) or A / China Hong Kong / 8 / 68( Figure 31B Comparison of the negative area under the curve peak in the area under the curve analysis of body weight loss in BALB / c mice with IgG in serum.

[0038] Figure 32 In vivo pharmacokinetics of FNI3 ("FNI3-LS"), FNI9 ("FNI9-LS"), and comparator antibodies FM08 and 1G01 ("1G01-LS") in tg32 mice are shown, all of which carry the M428L / N434S mutation. The calculated half-lives are highlighted by rectangles.

[0039] Figure 33 Summarizes the results of flow cytometry assays testing the binding of FNI3, FNI9, FNI17, and FNI19 to a panel of Group I IAV-, Group II IAV-, and influenza B virus (IBV) NA transiently expressed on mammalian cells at the indicated concentrations (μg / mL). Bold indicates NA from influenza viruses isolated from humans. The values ​​on the right scale show the range of calculated EC50s. Values ​​were selected based on the lowest concentration at which binding was observed.

[0040] Figure 34 In vitro inhibition of sialidase activity of group I (H1N1) and group II (H3N2) NA from IAV circulating in humans by FNI3, FNI9, FNI17, and FNI19 (reported as IC50 in μg / ml) is shown. Rectangles indicate group II (H3N2) NA with glycosylation at position 245 and corresponding sialidase inhibition values ​​(reported as IC50 in μg / ml).

[0041] Figure 35 In vitro inhibition of sialidase activity of a panel of human ancestral, Victoria lineage, and Yamagata lineage IBV NAs by FNI3, FNI9, FNI17, and FNI19 is shown (reported as IC50 in μg / ml).

[0042] Figure 36The in vitro neutralization activity of FNI3, FNI9, FNI17 and FNI19 against Group I (H1N1) IAV, Group II (H3N2) IAV and IBV NA, as measured by nucleoprotein (NP) staining, is shown. The neutralization activity of comparator anti-HA antibodies "FM08_LS" and "FHF11v9" was also measured.

[0043] Figure 37 Shown are the in vitro neutralizing activities of FNI3, FNI9, FNI17, FNI19 and oseltamivir (OSE) against Group I (H1N1) IAV, Group II (H3N2) IAV and IBV NA as measured by nuclear protein (NP) staining. 1 nM = 150 μl.

[0044] Figure 38A and Figure 38B Shown are in vitro inhibition of sialidase activity of NA from OSE-resistant influenza viruses by FNI3 and FNI9 as measured by the MUNANA assay (reported as IC50 in μg / ml). OSE-resistant IAVs were engineered using reverse genetics to carry oseltamivir-resistance (OSE) mutations. Figure 38A Inhibition of sialidase activity against Cal / 09N1 and Cal / 09N1-resistant OSE(H1N1) is shown. Figure 38B Inhibition of sialidase activity against Aichi / 68N2 and Aichi / 68N2-resistant OSE NA (H3N2) is shown.

[0045] Figure 39 Figure 20 shows antibody activation of FcγRIIIa (F158 allele) and FcγRIIa (H131 allele). Activation is measured using the luciferase reporter gene mediated by the NFAT in engineered Jurkat cells. Activation is assessed after incubation with A549 cells infected with H1N1 influenza strain A / Puerto Rico / 8 / 34 at a multiplicity of infection (MOI) of 6. FNI3, FNI9, FNI17 and FNI19 and comparator antibody "FM08_MLNS" carrying M428L / N434S mutations and a negative control antibody (FY1-GRLR) were tested.

[0046] Figure 40A and Figure 40B Shown in the presence of IAV ( Figure 40A ) and IBV( Figure 40B)NA after incubation with FcγRIIIa (V158 allele). Activation was measured using an NFAT-mediated luciferase reporter gene in engineered Jurkat cells after incubation with Expi-CHO cells transiently transfected with plasmids encoding different IAV and IBV NA. FNI3, FNI9, FNI17, and FNI19 were tested, along with a negative control antibody (FY1-GRLR).

[0047] Figure 41A and Figure 41B Shown in the presence of IAV ( Figure 41A ) and IBV( Figure 41B )NA after incubation with FcγRIIa (H131 allele). Activation was measured using an NFAT-mediated luciferase reporter gene in engineered Jurkat cells after incubation with Expi-CHO cells transiently transfected with plasmids encoding different IAV and IBV NA. FNI3, FNI9, FNI17, and FNI19 were tested, along with a negative control antibody (FY1-GRLR).

[0048] Figure 42 Shown is the negative area under the curve (EC50 in μg / ml) of the area under the curve analysis of weight loss in BALB / c mice infected with A / Puerto Rico / 8 / 34 (H1N1) or A / Hong Kong / 8 / 68 (H3N2) after treatment with FNI3, FNI9 or FM08-LS compared to IgG in serum. -1 The negative peak area from the vehicle group was calculated at IgG concentrations of μg / ml.

[0049] Figure 43A and Figure 43B Shown is the design of an in vivo study to evaluate the efficacy of FNI3_MLNS ( Figure 43A "mAb-03" in ) and FNI9_MLNS ( Figure 43A ) in DBA / 2J mice infected with IBV B / Victoria / 504 / 2000 (Yamagata) or B / Brisbane / 60 / 2008 (Victoria). Figure 43A The doses and viral strains used in the studies are indicated. Figure 43B The timeline and endpoints of the study are shown.

[0050] Figures 44A to 44DThe results of weight measurement of DBA / 2 mice infected with IBV B / Victoria / 504 / 2000 (Yamagata Prefecture) after pre-treatment with FNI3 or FNI9 over 15 days are shown. One day before infection with LD90 (90% lethal dose) of IBVB / Victoria / 504 / 2000 (Yamagata Prefecture), 6 mg / kg ( Figure 44A )、2mg / kg( Figure 44B )、0.6mg / kg( Figure 44C ) or 0.2mg / kg( Figure 44D ) Antibodies were administered. Body weights of mice administered vehicle control were also measured (left graph in each figure).

[0051] Figures 45A to 45D Figure 2 shows the body weight of DBA / 2 mice infected with IBV B / Brisbane / 60 / 2008 (Victoria) after pre-treatment with FNI3 or FNI9 over a period of fifteen days. Figure 45A )、2mg / kg( Figure 45B )、0.6mg / kg( Figure 45C ) or 0.2mg / kg( Figure 45D ) Antibodies were administered. Body weights of mice administered vehicle control were also measured (left graph in each figure).

[0052] Figure 46A and Figure 46B Shows the results of the experiment in which B / Victoria / 504 / 2000 (Yamagata Prefecture) was infected after pre-treatment with FNI3 or FNI9 ( Figure 46A ) or B / Brisbane / 60 / 2008(Victoria)( Figure 46B The weight loss of DBA / 2 mice pretreated with 5% naïve IgG4 (IgG4) from day 4 to day 14 post-infection (reported as the area under the weight change curve) was also measured in mice pretreated with vehicle control.

[0053] Figure 47A and Figure 47B Shows the results of the experiment on B / Victoria / 504 / 2000 (Yamagata Prefecture) infected with FNI3 or FNI9 ( Figure 47A ) or B / Brisbane / 60 / 2008(Victoria)( Figure 47B The survival rate of DBA / 2 mice pretreated with vehicle control was also measured.

[0054] Figure 48A and Figure 48B Shown is the conservation of FNI3 epitopes in IAV and IBV NA. Figure 48AAnalysis of N2 NA sequences from H1N2, H2N2, H3N2, and H5N2 IAVs (n=65,5262) ​​(top) and N1 NA sequences from H1N1 and H5N1 (n=58,954) (bottom) is shown. All sequences were isolated between 2000 and 2020. Acidic amino acids include: aspartic acid, glutamic acid; basic amino acids include: arginine, histidine, lysine; hydrophobic amino acids include: isoleucine, leucine, tryptophan, valine, alanine, proline; neutral amino acids include: asparagine, glutamine; and polar amino acids include: serine, threonine, glycine, tyrosine. Figure 48A The residues surrounded by boxes in Figure 48B Some of the amino acids described in the figure below. Figure 48B The table in shows the important FNI3 interacting residues in N2 NA and the corresponding FNI3 CDRH3 residues.

[0055] Figure 49 FNI3 epitope conservation in IBV NA is shown. The IBV NA sequence from B / Brisbane / 60 / 2008 ("FluB Victoria" in the figure; N = 7,814; top) was analyzed along with the IBV NA sequence from B / Victoria / 504 / 2000 ("FluB Yamagata" in the figure; N = 13,243; bottom). Acidic amino acids include aspartic acid, glutamic acid; basic amino acids include arginine, histidine, lysine; hydrophobic amino acids include isoleucine, leucine, tryptophan, valine, alanine, proline; neutral amino acids include asparagine, glutamine; and polar amino acids include serine, threonine, glycine, tyrosine. Boxed residues indicate primary NA residues that interact with FNI3 HCDR3 and are 100% conserved between IAV N1 / N2 and IBV.

[0056] Figure 50A and Figure 50B The in vivo pharmacokinetics of FNI antibodies carrying MLNS Fc mutations (FNI3 ("FNI3-LS"), FNI9 ("FNI9-LS"), FNI17 ("FNI17-LS"), FNI19 ("FNI19-LS")) and the comparator antibody FM08-MLNS in SCID tg32 mice over 30 days after administration are shown. Concentrations (reported in μg / ml) over time are shown in Figure 50A Shown in. Figure 50B The table in shows half-life (reported in days), AUC (reported in days*μg / ml), clearance (reported in μg / ml) and volume (reported in ml).

[0057] Figure 51 Shown is the conservation of the first five interacting residues within the FNI NA epitope in Group I IAV, Group II IAV, and IBV from 2009 to 2019.

[0058] Figure 52 The in vitro neutralization activity of FNI9, oseltamivir (OSE) and comparator antibody "FM08" against H3N2 A / Hong Kong / 8 / 68 virus measured by nucleoprotein (NP) staining is shown. Calculated IC50 (in nM), IC80 (in nM) and maximum inhibition (reported as a percentage) are shown below the graph.

[0059] Figure 53 Shown is the antibody activation of "GAALIE" Fc variant antibody (comprising the G236A / A330L / I332E mutation in Fc) to FcγRIIIa (F158 allele) and FcγRIIa (H131 allele). Activation is measured using the luciferase reporter gene mediated by the NFAT in engineered Jurkat cells. Activation is assessed after incubation with A549 cells infected with H1N1 influenza strain A / Puerto Rico / 8 / 34 at a multiplicity of infection (MOI) of 6. FNI3, FNI9, FNI17 and FNI19 and FNI3, FNI9, FNI17 and FNI19 antibodies carrying the GAALIE mutation (suffix "-GAALIE") were tested. Comparator antibody "FM08_LS" and negative control antibody (FY1-GRLR) were also tested.

[0060] Figure 54 The design of the inter-experimental in vivo study comparing the protective activity of FM08_LS with FNI3_LS and FNI9_LS in BALB / c mice infected with IAV A / Puerto Rico / 8 / 34 or A / Hong Kong / 8 / 68 is shown. The table shows the doses and virus strains used in the study. The timeline and endpoints of the study are as follows: Figure 26B The timeline and endpoints shown are the same. Body weight data from Experiment A ("Exp-A") are 27A to 27D (FNI9-LS, A / Puerto Rico / 8 / 34) and 28A to 28D (FNI9-LS, A / Hong Kong, China / 8 / 68) is shown.

[0061] Figure 55The design of an in vivo study evaluating the bioefficacy of oseltamivir (OSE) in female BALB / c mice infected with A / V / Puerto Rico / 8 / 34 is shown. The timeline shows the time of infection, OSE dosing, and study endpoints. On day 0, 10 mg / kg OSE was administered by oral gavage, starting two hours before infection with 10 times the LD50 (50% lethal dose) of A / V / Puerto Rico / 8 / 34. OSE was administered at the same dose 6 hours after infection and then twice daily until day 6 after infection.

[0062] Figure 56 Shown are body weight measurements over fourteen days of BALB / c mice infected with H1N1 A / Puerto Rico / 8 / 34 following pretreatment with oseltamivir (OSE). Weight loss was also measured in mice pretreated with vehicle control (H2O).

[0063] Figure 57 Shown are the survival rates of BALB / c mice infected with H1N1 A / Puerto Rico / 8 / 34 over fourteen days after treatment with oseltamivir (OSE). The survival rates of mice pretreated with vehicle control (H2O) were also measured.

[0064] Figure 58 Virus titers in lung homogenates from BALB / c mice treated with OSE and infected with H1N1 A / Puerto Rico / 8 / 34 are shown. Lung tissue was collected two and four days after infection. Titers are reported as 50% tissue culture infectious doses per gram of tissue (TCID50 / g).

[0065] Figures 59A to 59E In vitro inhibition of sialidase activity of IAV NA and IBV NA by FNI9 and certain FNI9 variants is shown (reported as IC50 in μg / ml). Neutralization activity of FNI9 and FNI9 variants was against Group I (H1N1) IAV NA1 (from H5N1 A / Vietnam / 1203 / 2004) Figure 59A ), NA2 from H3N2 A / Tanzania / 205 / 2010 ( Figure 59B ) and NA9 from H7N9 A / Hong Kong, China / 56 / 2015 ( Figure 59C ) are shown. The neutralizing activity of FNI9 and variants is against BNA2 ( Figure 59D ) and BNA7 from B / Perth / 211 / 2011( Figure 59E In these figures, “FNI9-v6”, “FNI9-v7”, “FNI9-v8” and “FNI9-v9” are shown. Figure 67 shown, and with e.g. Figures 70 to 72The FNI9 variant sequences shown are different for "-VH.6," "-VH.7," "-VH.8," and "-VH.9."

[0066] Figure 60 Additional properties of FNI9 VH are shown. A map of the total surface charge of FNI9 was generated using PyMOL, along with pK values ​​and resolution (in unit reports).

[0067] Figure 61 Shown are the binding energies between the FNI antibodies FNI3, FNI9, FNI17, and FNI19 and the highly conserved residues on NA involved in interactions with sialic acid.

[0068] Figure 62 Shown is the binding of FNI3, FNI9, FNI 17, and FNI 19 to NA expressed on mammalian cells infected with the H1N1 porcine Eurasian avian (EA) strain A / swine / Jiangsu / Jiangsu / J004 / 2018, measured by flow cytometry. Mock antibody staining is shown as a negative control.

[0069] Figure 63 Shown are the binding kinetics of FNI3, FNI9, and FNI17 to N9 NA as measured by biolayer interferometry (BLI). KD was calculated from the ratio of kdis / kon, where kdis is the dissociation calculated as (1 / s) and kon is the association calculated as (1 / Ms).

[0070] Figure 64 Shown are in vitro inhibition of sialidase activity of Group II H7N9 A / Anhui / 1 / 2013 IAV NA by FNI3, FNI9, FNI17, FNI17-V19, FNI19, and FNI19-v3 (reported in ng / ml).

[0071] Figure 65 Shown is the antibody activation of Fc γ RIIIa (V158 allele) after incubation with II group H7N9 A / Anhui / 1 / 2013IAV.After incubation with Expi-CHO cells transiently transfected with the plasmid encoding the N9 from A / Anhui / 1 / 2013IAV, activation was measured using the luciferase reporter gene of the NFAT mediation in the Jurkat cells of through engineering approaches. FNI3, FNI9, FNI17 and FNI19 and negative control antibody (FY1-GRLR) were tested.

[0072] Figures 66A to 66CAntibody activation of FcγRIIa (H131 allele) by the "GAALIE" Fc variant antibody (comprising G236A / A330L / I332E mutations in Fc) is shown. Figure 66A H1N1 A / California / 07 / 2009; Figure 66B H3N2 A / Hong Kong, China / 8 / 68) and IBV ( Figure 66C Activation was measured using an NFAT-mediated luciferase reporter gene in engineered Jurkat cells after incubation with Expi-CHO cells transiently transfected with a plasmid containing B / Malaysia / 2506 / 2004)NA. FNI3, FNI9, FNI17, and FNI19 antibodies were tested, as well as FNI3, FNI9, FNI17, and FNI19 antibodies carrying a GAALIE mutation (suffix "-GAALIE" in the figure). Comparator antibody "FM08_LS" and a negative control antibody (FY1-GRLR) were also tested. The measured values ​​for FM08_LS and FY1-GRLR were Figures 66A to 66C The lowest.

[0073] Figure 67 Antibody titers are shown for certain FNI3, FNI9, FNI17, or FNI19 mAbs, including increases / decreases in variants compared to wild type.

[0074] Figure 68 Shown is the binding of FNI9 and certain FNI9 variants (FNI9 variants (VH SEQ ID NO.: 2, VL SEQ ID NO.: 37) to FNI9-v9) to Group I IAV, Group II IAV, and IBV NA as measured by flow cytometry (reported as MFI). The MFI values ​​of the variants were normalized to the MFI value of wild-type FNI9. Figure 68 The FNI9 variants shown are similar to e.g. Figures 70 to 72 The FNI9 variant sequences shown are different for "-VH.6," "-VH.7," "-VH.8," and "-VH.9."

[0075] Figures 69A to 69D The binding kinetics of FNI3-LS, FNI9-LS, FNI17-LS and FNI19-LS, as well as FNI3-LS, FNI9-LS, FNI17-LS and FNI19-LS antibodies carrying the GAALIE mutation (suffix "-GAALIE" in the figure) to different FcγRs are shown as measured by biolayer interferometry (BLI). Arrows indicate the curves for FNI17-LS and FNI17-LS-GAALIE. Figure 69A Binding to FcγRIIA(H) is shown, Figure 69BBinding to FcγRIIA(R) is shown, Figure 69C Binding to FcγRIIIA(F) is shown, and Figure 69D Binding to FcγRIIIA(V) is shown.

[0076] Figure 70 The mutations introduced into wild-type FNI9 VH or VL to generate additional variant antibodies are shown.

[0077] Figure 71 The amino acid sequence of the FNI9 wild-type ("WT") variable domain is shown. Figure 70 FNI9 antibody variable domains with one or more mutations as indicated.

[0078] Figure 72 Summarizes the following Figure 70 Certain FNI9 variant antibodies of the present disclosure (FNI9-v13.8-FNI9-v12.7) have one or more mutations as shown.

[0079] Figure 73 The FcγR and C1q binding affinities of certain IgG1 Fc variant antibodies are shown (by mesoscale discovery-based assay (MSD; using electrochemiluminescence)) and other properties. The Fc variants shown starting from the third row ("G236A_E272Y_S298N" and below) were identified using an iterative discovery workflow. The G236A_A330L_I332E variant was used as a comparator. The Fc variant antibodies were tested for binding to FcγRIIA-H (high affinity H158 allele), FcγRIIB, FcγRIIA-R (low affinity R131 allele), FcγRIIIA-V (high affinity VI 58 allele), FcγRIIIA-F (low affinity F158 allele), FcγRIIIB and FcRn. Data are reported as fold change in binding compared to wild-type IgG1. Also shown are the FcγRIIA / FcγRIIB binding ratio relative to wild-type IgG1, as well as production titer (mg / mL) and Tm (°C).

[0080] Figures 74A to 74C The effect of fucosylation on the production and purification of twenty Fc variant antibodies is shown. Variants were expressed in the absence ("no 2FF") or presence ("+2FF") of 2-deoxy-2-fluoro-L-fucose (2FF); 2FF reduces fucosylation. Figure 74A Shown are antibody titers as determined using a Protein A column. Figure 74B Yields resulting from two repeated purifications are shown. Figure 74CThe table in summarizes the theoretical maximum yield and the average yield, both measured in μg, as well as the calculated average recovery and protein concentration of the second elution (measured in μg / ml). The Fc variants were purified using two elutions and pooled before yield determination.

[0081] Figures 75A to 75B The FcγR binding and other properties of the Fc variants are summarized relative to wild-type Fc. Bars and values ​​indicate the fold change in binding compared to wild-type Fc. The indicated Fc variants were not treated with 2FF. Figure 75A Binding to FcγRIIA-H (high affinity), FcγRIIA-R (low affinity), FcγRIIB, FcγRIIIA-V (high affinity), FcγRIIIA-F (low affinity), and FcRn (at pH 6) is shown. Figure 75B Further shown are the FcγRIIA-H / FcγRIIB binding ratio, as well as C1q binding and complement-dependent cytotoxicity (CDC), with the WT "baseline" value indicated by the red vertical dashed line. Binding was measured by a meso scale discovery-based assay (MSD; employing electrochemiluminescence).

[0082] Figure 76 Binding of certain Fc variants to FcγRIIA-H (high affinity) and FcγRIIB is shown. Graphs connected by lines represent the same variant. Variants shown were not treated with 2FF.

[0083] Figures 77A to 77B FcγR signaling through different FcγRs is shown, as measured using a reporter cell assay (Promega; the cells tested expressed one type / allele of FcγR, as indicated). The Fc variants shown were fucosylated ("fuc"; 124A / 124B) or defucosylated ("afuc"; 124B), as indicated in the figure. Values ​​were calculated from the average of three experiments and indicate the fold change (in linear representation) of the area under the curve (plotted in logarithm) compared to wild-type Fc.

[0084] Figure 78 The properties of certain variant Fcs are summarized. Antibodies containing the indicated Fcs were expressed as recombinant human IgG1. Binding was measured by a mesoscale discovery-based assay (MSD; using electrochemiluminescence). Values ​​represent fold changes compared to antibodies containing wild-type, fucosylated human IgG1 Fc. Also shown are fold changes in FcγR signaling, as measured using a reporter cell assay.

[0085] Figure 79Results of experiments measuring the following are shown: FcγR binding of certain Fc variant antibodies; binding ratios of FcγRIIA alleles to FcγRIIB; C1q binding; melting temperature; and FcRn binding. The anti-influenza A antibody FY1 (Kallewaard et al., Cell. 2016 Jul 28; 166(3): 596-608) was expressed as a recombinant IgG1m3 with M428L and N434S mutations in CH3 and the indicated combination mutations elsewhere in the Fc. Binding was measured by a mesoscale discovery-based assay (MSD; using electrochemiluminescence) (one study). Binding data are shown as fold change relative to FY1rIgG1m3-MLNS without other Fc mutations. FcγR binding was confirmed by FcγR signaling using a reporter cell assay (NFAT-driven luciferase) (Promega).

[0086] Figure 80 shows the measurements as Figure 79 Results of additional experiments characterizing antibodies in . In these experiments, FY1 was expressed as a recombinant IgG1m3 without the M428L and N434S mutations (i.e., with wild-type IgG1m3 CH1-CH3 or with the mutations indicated in the table). FY1-rIgG1m3 and FY1-rIgG1m3-GAALIE antibodies were independently produced and measured twice in the first plate; average data are shown. FY1-rIgG1m3-GA antibody was independently produced twice in the first and second plates. For other variants, single measurements were performed. Binding was measured by a mesoscalediscovery-based assay (MSD; using electrochemiluminescence). Binding data are shown as fold change relative to FY1 rIgG1m3 with wild-type Fc. FcγR binding / activation was performed using a reporter cell assay (NF AT-driven luciferase) (Promega).

[0087] Figure 81 The use of afucosylated Fc variant antibody to measure Figure 80Results of additional experiments characterizing the features in . Antibodies were produced in the presence of 2FF to obtain defucosylated glycans. In these experiments, FY1 was expressed as a recombinant IgG1m3 without the M428L and N434S mutations (i.e., with wild-type IgG1m3 CH1-CH3 or with the mutations indicated in the table). FY1-rIgG1m3 and FY1-rIgG1m3-GAALIE antibodies were independently produced and measured twice in the first plate; average data are shown. FY1-rIgG1m3-GA antibody was independently produced twice in the first and second plates. For the other variants, single measurements were performed. Binding was measured by a mesoscale discovery-based assay (MSD; using electrochemiluminescence).

[0088] Figure 82 Activation / signaling of FcγRIIA by anti-influenza FY1 antibodies with variant Fc as indicated in the legend is shown. Target cells were A549 cells expressing FluA H1N1 HA, and reporter cells were Jurkat cells expressing FcγRIIA (H131 allele) and luciferase under the control of the NF AT promoter.

[0089] Figures 83A to 83B Activation / signaling of FcγRIIIA by anti-influenza FY1 antibodies with variant Fc as indicated in the legend is shown. Target cells are A549 cells expressing FluA H1N1 HA, and reporter cells are Jurkat cells expressing FcγRIIIA (F158 low-affinity allele (A) or V158 high-affinity allele (B)) and luciferase under the control of the NF AT promoter.

[0090] Figures 84A to 84ICertain anti-HBV ("HBC34-v40"; see PCT Publication No. WO 2021 / 262840) Fc variant antibodies are disclosed. (A) Flow cytometry showing CD83 expression on monocyte-derived dendritic cells (moDCs) (expressing the indicated FcγRs) in the presence of the indicated HBC34-v40 Fc variant antibodies (50 μg / mL) and 30 IU / mL HBsAg from HBV+ patient serum. (B) Flow cytometry showing CD83 expression on moDCs in the presence of the indicated concentrations of HBC34-v40 Fc variant antibodies (50 μg / mL) and HBsAg from HBV+ patient serum (BioIVT). The left graph is from an experiment using the first method of aspirating / generating antibody:HBsAg immune complexes; the right graph is from an experiment using the second method of aspirating / generating antibody:HBsAg immune complexes. (C) Expression of CD25 (activation marker) and CFSE (proliferation marker) on autologous CD4+ memory T cells (from HBV vaccine recipients) incubated for 5 days with moDC from the same donor; moDC were first activated overnight with 100 IU / mL HBsAg (from two patient sera) and 50 μg / mL HBC34-v40 Fc variant antibody. LS-GAYL variants were compared in one experiment. (D) CD14+ monocytes were stimulated with IL-4 and GM-CSF for 6 days. MoDC were treated overnight with antigen and HBC34-v40 Fc variant antibody (50 μg / mL) and then co-cultured with HLA-matched (HLA-DR-restricted) transgenic Jurkat cells expressing an HBsAg-specific human TCR. The readout was the GFP-NFAT reporter gene from Jurkat cells. (E) Comparison of three independent replicates of the Jurkat TCR reporter assay at 0.125 μg / mL antibody. (F) Summary of data from the different assays. (G) Schematic diagram of the experimental setup used to assess ex vivo proliferation of T cells from FcγR-expressing mice immunized and boosted with HBsAg vaccine; memory CD44+CD4+ T cells were sorted, labeled with CFSE, co-cultured with immune complex (antibody:HBsAg antigen)-pulsed BMDCs, and proliferation assessed on day 6. SEB = Staphylococcal enterotoxin B from Staphylococcus aureus (S. aureus). (H) CD4 expression and CFSE staining on (500,000) CD4+ memory T cells as in (G), after BMDCs (50,000) were stimulated with immune complexes containing the indicated HBC34-v40 Fc variant antibodies (20 μg / mL) and HBsAg (1000 IU / mL). SEB = 1 μg / mL; Mann-Whitney assay.(I) (Left) Frequency of CFSE-low CD4+CD44+ T cells after incubation with moDC pretreated with HBsAg alone, antibody alone, or SEB; (Right) Frequency of CFSE-low CD4+CD44+ T cells after incubation with moDC pretreated with the indicated concentrations of HBsAg and the indicated HBC34-v40 Fc variant antibodies. moDC were derived from mice transgenic for expressing human FcγRs, and T cells were derived from HuFcγR mice (n=4 independent experiments) or C57Bl / 6 mice (n=1 experiment). 50,000 moDCs + 500,000 T cells were tested. SEB = 1 μg / mL; Mann-Whitney test.

[0091] Figures 85A to 85B Shown are in vitro inhibition of sialidase activity of NA by FNI9 and FNI9-v5 as measured by the MUNANA assay. Figure 85A Inhibition of sialidase activity against N1 from H5N1A / Vietnam / 1203 / 2004 is shown. Figure 85B Inhibition of sialidase activity against N2 from H3N2 A / Tanzania / 205 / 2010 is shown.

[0092] Figure 86 Shown are the binding affinities of FNI9 and FNI9-v5 Fab fragments to the N2 antigen with or without a glycosylation site at position 245, as measured by surface plasmon resonance (SPR). Binding affinities are reported as equilibrium constants, KD, in nM. The label "+glcy245" indicates the presence of a glycosylation site at position 245. Asterisks indicate the method by which the Fab fragments were generated, with "r" indicating generation by recombinant expression and "d" indicating generation by digestion.

[0093] Figures 87A to 87B Shown are in vitro inhibition of N2 sialidase activity in pseudotyped viral particles by FNI9 and FNI9-v5 as measured by ELLA (enzyme-linked lectin assay). Figure 87A Inhibition of sialidase activity on A / Switzerland / 2017 pseudovirions is shown. Figure 87B Inhibition of sialidase activity against A / Kansas / 14 / 2017 pseudovirions is shown.

[0094] Figure 88 In vitro neutralization of influenza by FNI9 and FNI9-v5 is shown (reported as EC50 in μg / ml).

[0095] Figure 89The mutations in the VH and VL (VK) domains of certain variants of the FNI9 parent antibody are summarized. The "FNI9" and "FNI9-v1.1" antibodies have these amino acid sequences. FNI9-v1.1 was produced simultaneously with the variants to control for any changes in production conditions.

[0096] Figure 90 The production titer and size exclusion chromatography (SEC) characteristics of the FNI9 antibody are shown. The SEC characteristic indication of "qualified" was no significant aggregation (<3% high molecular weight species) or fracture (<3% low molecular weight species) observed by UHPLC-SEC. The SEC characteristic indication of "not evaluated" was not able to evaluate the SEC characteristics because the antibody was not produced in sufficient titers in the transient transfection. For productivity, the antibody titer in the supernatant of the cells of "too low" indication transient transfection was lower than the detection limit of the quantitative method (protein A binding on BLI). "FNI9-v1.1" has the same sequence as FNI9.

[0097] Figures 91A to 91B In vitro inhibition of sialidase activity of FNI9 variants against N1, N2, and N9 NA as measured by the MUNANA assay is shown. Values ​​indicate the antibody concentration (in μg / ml) that resulted in 50% inhibition of sialidase activity. The neuraminidase antigen concentration used for the assay is indicated in the legend. "FNI9-v1.1" has the same sequence as FNI9.

[0098] Figures 92A to 92B In vitro inhibition of sialidase activity of the indicated pseudovirus-derived NA by FNI9 variants, as measured by ELLA, is shown. Values ​​indicate the antibody concentration (in μg / ml) that resulted in 50% inhibition of sialidase activity. The neuraminidase antigen concentration used for the assay is indicated in the legend. "FNI9-v1.1" has the same sequence as FNI9.

[0099] Figures 93A to 93D Shown is the binding of FNI9 antibodies to transiently expressed NA in mammalian cells as measured by flow cytometry and reported in units of MFI. Figure 93A Binding is shown to N1 from A / California / 07 / 2009 and A / California / 07 / 2009I223R / H275Y and N2 in A / Washington / 01 / 2007 and A / Washington / 01 / 2007R292K. Figure 93B Binding to N2 from A / Switzerland / 8060 / 2017, A / Kansas / 14 / 2017, A / Cambodia / 2020, and A / South Australia / 34 / 2019 is shown. Figure 93CBinding to IBV NA from B / Malaysia / 2506 / 2004 (Victoria), B / Brisbane / 2008 (Victoria), B / Yamanashi / 166 / 1998 (Yamagata), and B / Phuket / 3073 / 2013 (Yamagata) is shown. Figure 93D Binding to N2 from A / Leningrad / 134 / 17 / 57 and A / Perth / 16 / 2009 and N9 from A / Anhui / 1 / 2013 is shown. Figures 93A to 93D For each test condition (e.g. Figure 93A 9 in the Figure 1), the bars in each graph correspond from left to right to the antibodies indicated from top to bottom and from left to right in the corresponding legend. For example, Figure 93A The first three bars from the left above "N1_A_Calif_07_2009" correspond to FNI9v-1.1, FNI9-v4.1, and FNI9-v4.7. The antibodies FNI9-v1.1, FNI9-v4.1, FNI9-v8.1, FNI9-v13.8, and FNI9-v9.1 are indicated by the patterns or shading in the bars.

[0100] Figure 94 The affinity of antibodies "FNI9-v4.1," "FNI9-v8.1," "FNI9-v9.1," and "FNI9-v13.8" (expressed as IgG1) for IAV and IBV NA antigens, as measured by SPR, is shown. The NA antigen class is indicated, with "FluB" indicating NA from IBV, "N1" indicating N1 NA, "A / H3N2-gly245" indicating N2 NA from an H3N2 strain without glycosylation at position 245, "A / H3N2+gly245" indicating N2 NA from an H3N2 strain with glycosylation at position 245, and "N9" indicating N9 NA. Values ​​indicate the fold change in affinity compared to the parental antibody "FNI9-v1.1" (same sequence as FNI9).

[0101] Figures 95A to 95B Shown is the affinity of Fab fragments from FNI9-v1.1 (same sequence as FNI9), FNI9-v4.1, FNI9-v8.1, and FNI9-v13.8 for the N2 antigen as measured by SPR. Binding to A / Tanzania / 205 / 2010, A / South Australia / 34 / 2019, and A / Hong Kong / 2671 / 2019 with (labeled "+gly245") or without (labeled "-gly245") glycosylation at position 245 was measured. Figure 95ABinding affinities reported as equilibrium constants KD in nM are shown. Figure 95B Shown are binding affinities reported as fold change compared to Fabs from the parental antibody FNI9-v1.1.

[0102] Figures 96A to 96C FNI9-v1.1 (same sequence as FNI9) as measured by biolayer interferometry (BLI) is shown ( Figure 96A )、FNI9-v8.1( Figure 96B ) and FNI9-v9.1( Figure 96C ) binding kinetics to N9 NA. Dissociation is reported as kdis (1 / s), association is reported as ka (1 / Ms), and KD (M) is calculated from the ratio of kdis / ka.

[0103] Figure 97A In vitro neutralization activity (reported as EC50 in μg / ml) of FNI9-v1.1 (same sequence as FNI9), FNI9-v8.1, FNI9-v4.1, FNI9-v9.1, and FNI9-v13.8 against a panel of seasonal IAVs and IBVs is shown. Strains carrying glycosylation at position 245 are indicated. Figure 97B Shown are in vitro inhibition (reported as IC50 in ng / ml) of sialidase activity of a panel of seasonal Group I (H1N1) IAV, Group II (H3N2) IAV, and IBV NA by FNI9-v1.1 and FNI9-v8.1.

[0104] Figures 98A to 98G In vitro inhibition of sialidase activity of N1, N2, and N9 NA by certain FNI9 variants as measured by the MUNANA assay is shown. FNI9-v4.1, FNI9-v4.7, FNI9-v5.1, FNI9-v5.7, FNI9-v6.1, FNI9-v6.7, FNI9-v7.1, FNI9-v7.7, FNI9-v8.7, FNI9-v8.1, and FNI9-v13.8 antibodies were tested. FNI9, FNI9-v1.1, and FNI9-v5 were tested as comparator antibodies. Inhibition of sialidase activity of N1 ( Figure 98A ), N2 in A / Tanzania / 205 / 2010 ( Figure 98B ), N2 in A / Switzerland / 8060 / 2017( Figure 98C ), N2 in A / South Australia / 34 / 2019( Figure 98D ), N2 in A / Hong Kong, China / 2671 / 2019( Figure 98E)、N2(+Gly245) in A / Tanzania / 205 / 2010( Figure 98F ) and N9 in A / Hong Kong / China / 56 / 2015( Figure 98G ) for sialidase activity inhibition.

[0105] Figures 99A to 99G Shows in vitro inhibition of sialidase activity of certain FNI9 variants against N1, N2, and N9 NA as measured by the MUNANA assay. Antibodies FNI9-v6.1, FNI9-v9.1, FNI9-v9.7, FNI9-v11.1, FNI9-v11.7, FNI9-v12.1, and FNI9-v12.7 were tested. FNI9, FNI9-v1.1 (identical to FNI9 and produced with the variants to control for any changes in production conditions), and FNI9-v5 were tested as comparator antibodies. Shows inhibition of N1 in A / Vietnam / 1203 / 2004( Figure 99A ), N2 in A / Tanzania / 205 / 2010( Figure 99B ), N2 in A / Switzerland / 8060 / 2017( Figure 99C ), N2 in A / South Australia / 34 / 2019( Figure 99D ), N2 in A / Hong Kong / China / 2671 / 2019( Figure 99E ), N2(+Gly245) in A / Tanzania / 205 / 2010( Figure 99F ) and N9 in A / Hong Kong / China / 56 / 2015( Figure 99G ) for sialidase activity inhibition.

[0106] Figures 100A to 100F Shows in vitro inhibition of sialidase activity of certain FNI9 variants against the indicated pseudovirus-derived NA as measured by ELLA. Antibodies FNI9-v4.1, FNI9-v4.7, FNI9-v5.1, FNI9-v5.7, FNI9-v6.1, FNI9-v6.7, FNI9-v7.1, FNI9-v7.7, FNI9-v8.7, FNI9-v8.1, and FNI9-v13.8 were tested. FNI9, FNI9-v1.1, and FNI9-v5 were tested as comparator antibodies. Shows inhibition of H7N3 A / Ck / Ja / 2017( Figure 100A ), H5N6 A / Ck / Suzhou / 2019( Figure 100B ), H5N6 A / Hangzhou / 2021( Figure 100C ), H7N7 A / Ck / 621572 / 03( Figure 100D ), H5N8 A / Ck / Russia / 2020( Figure 100E) and H7N9 A / Anhui / 1 / 2013( Figure 100F )'s sialidase activity inhibition.

[0107] Figures 101A to 101F In vitro inhibition of sialidase activity of the indicated pseudovirus-derived NA by certain FNI9 variants as measured by ELLA is shown. FNI9-v6.1, FNI9-v9.1, FNI9-v9.7, FNI9-v11.1, FNI9-v11.7, FNI9-v12.1, and FNI9-v12.7 antibodies were tested. FNI9, FNI9-v1.1, and FNI9-v5 were tested as comparator antibodies. Inhibition of sialidase activity of the indicated pseudovirus-derived NA by certain FNI9 variants as measured by ELLA is shown. Figure 101A )、H5N6 A / Ck / Suzhou / 2019( Figure 101B )、H5N6 A / Hangzhou / 2021( Figure 101C )、H7N7 A / Ck / 621572 / 03( Figure 101D )、H5N8 A / Ck / Russia / 2020( Figure 101E ) and H7N9 A / Anhui / 1 / 2013( Figure 101F )'s sialidase activity inhibition.

[0108] Figures 102A to 102B Shown are the in vitro neutralizing activities of FNI9, FNI19-v3, FNI17-v19, and FNI17-v19-LS against Group I (H1N1) IAV, Group II (H3N2) IAV, and IBV NA, measured by nucleoprotein (NP) staining. The rectangle indicates the Group II (H3N2) NA carrying a glycosylation at position 245. The neutralizing activity of the comparator antibody 1G01 was also measured.

[0109] Figures 103A to 103B Shown are estimates of the median EC90 values ​​(reported in μg / ml) for FNI9-v1.1 or FNI9-v8.1 against a panel of Group I (H1N1) IAV, Group II (H3N2) IAV, and IBV NA, determined by nonlinear regression.

[0110] Figure 104 The median EC90, tissue-adjusted EC90 at the 25th percentile of the data, and tissue-adjusted EC90 at the 5th percentile of the data for FNI9-v8.1 against a panel of Group I (H1N1) IAV, Group II (H3N2) IAV (with or without glycan-245), and IBV NA are summarized.

[0111] Figure 105In vitro neutralization activity of FNI9 against H3N2 A / Singapore / INFIMH-16-0019 / 2016 is shown (reported in μg / ml). Neutralization activity of the anti-HA comparator antibody FM08-LS was also measured.

[0112] Figure 106 Shown are dose-response curves for the in vitro neutralizing activity of FNI9 and FNI17-v19 against H3N2 A / Singapore / INFIMH-16-0019 / 2016.

[0113] Figure 107 Shown are viral titers in lung homogenates from BALB / c mice treated with FNI9-v1.1, FNI9-v8.1, or FNI17-v19 prior to infection with H3N2 A / Singapore / INFIMH-16-0019 / 2016. Antibodies were administered at 3 mg / kg, 0.9 mg / kg, 0.3 mg / kg, 0.1 mg / kg, or 0.03 mg / kg. Viral titers were also measured in mice treated with OSE (10 mg / kg or 20 mg / kg) or anti-HA comparator antibody FM08-LS. Lung tissue was collected four days after infection. Titers were reported as the logarithm of the 50% tissue culture infectious dose (Log TCID50 / g) per gram of tissue.

[0114] Figures 108A to 108D Virus titers in lung homogenates from BALB / c mice treated with FNI9-v8.1 prior to infection with IAV or IBV are shown. Figure 108A ), H3N2 A / Singapore / INFIMH-16-0019 / 2016( Figure 108B )、B / Victoria / 504 / 2000(Yamagata Prefecture)( Figure 108C ) or B / Brisbane / 60 / 2008(Victoria)( Figure 108D ) were administered at 3 mg / kg, 0.9 mg / kg, 0.3 mg / kg, or 0.1 mg / kg before administration. Viral titers were also measured in mice treated with OSE (10 mg / kg or 20 mg / kg) or the anti-HA comparator antibody FM08_LS. Lung tissue was collected four days after infection. Titers are reported as the logarithm of the 50% tissue culture infectious dose per gram of tissue (Log TCID50 / g).

[0115] Figures 109A to 109D Virus titers in lung homogenates from BALB / c mice treated with FNI9-v8.1 prior to infection with IAV or IBV are shown. Figure 109A), H3N2 A / Singapore / INFIMH-16-0019 / 2016( Figure 109B )、B / Victoria / 504 / 2000(Yamagata Prefecture)( Figure 109C ) or B / Brisbane / 60 / 2008(Victoria)( Figure 109D Antibodies were administered at 3 mg / kg, 0.9 mg / kg, 0.3 mg / kg, or 0.1 mg / kg prior to administration of the antibody. Titers were reported as log plaque forming units per gram of tissue (Log pfu / g).

[0116] Figure 110A and Figure 110B In vitro neutralization data for FNI9-v8.1 against a panel of H1N1 IAV, H3N2 IAV (with or without a glycosylation site at position 245), and IBV are shown.

[0117] Figure 111 The in vitro neutralization statistics of FNI9-v8.1 against all strains of H1N1 IAV, H3N2 IAV, H3N2 IAV (without a glycosylation site at position 245), H3N2 IAV (with a glycosylation site at position 245), and IBV are summarized.

[0118] Figures 112A to 112B The in vitro neutralizing activity of FNI9-v8.1, FNI17 and FNI19 against Group I (H1N1) IAV, Group II (H3N2) IAV and IBV NA as measured by nucleoprotein (NP) staining is shown. The neutralizing activity of comparator antibody 1G01 was also measured. For each strain, data from two independent experiments are shown.

[0119] Figures 113A to 113D Reports FM08 and FNI9-v8.1 are shown for H1N1 A / Puerto Rico / 34 ( Figure 113A and Figure 113B ) and H3N2 A / Tasmania / 503 / 2020( Figure 113C and Figure 113D ) of the combined activity of the in vitro neutralization matrix ( Figure 113A and Figure 113C ) and collaboration diagrams ( Figure 113B and Figure 113D ).

[0120] Figures 114A to 114BComplement dependent cytotoxicity (CDC) mediated by FNI9-v8.1-LS (containing the M428L and N434S mutations in the Fc) against MDCK-LN cells infected with H1N1 A / Puerto Rico / 8 / 34 in the presence of guinea pig complement is shown. CDC was also measured for the anti-HA comparator antibody FM08_LS and the Fc silent negative control FNI9-v8.1-GRLR. Figure 114A was reported as antibody-dependent killing in Figure 114B The values ​​are reported as the area under the curve.

[0121] Figures 115A to 115B Figure 2 shows antibody-dependent cellular cytotoxicity (ADCC) mediated by FNI9-v8.1-LS against A549 cells infected with H1N1 A / Puerto Rico / 8 / 34 in the presence of human natural killer cells. ADCC was also measured for the anti-HA comparator antibody FM08_LS and the Fc-silenced negative control FNI9-v8.1-GRLR. Figure 115A was reported as antibody-dependent killing in Figure 115B The values ​​are reported as the area under the curve.

[0122] Figures 116A to 116B Antibody-dependent cellular phagocytosis (ADCP) was performed by serial dilutions of FNI9-v8.1-LS using peripheral blood mononuclear cells (PBMCs) as a monocyte source and PKH67-labeled ExpiCHO cells expressing N2 NA as target cells. The y-axis indicates the percentage of monocytes that were double positive for CD14 and PKH67. For all assays, FNI9-v8.1-GRLR was used as an Fc silencing negative control, and the results are shown as dose-response curves (a, b, c) and the area under the curve (AUC) (d, e, f) representing n = 1 (d, e) or n = 2 (f) experimental replicates (black dots).

[0123] Figures 117A to 117D The antibody concentrations on day 0 and Figures 108A to 108D Correlation between in vivo viral lung titers. Lung viral titers 4 days after infection with H1N1 A / Puerto Rico / 8 / 34, H3N2A / Singapore / 2016, B / Victoria / 504 / 2000, and B / Brisbane / 60 / 2008 viruses are plotted as a function of serum mAb concentrations before infection (day 0).

[0124] Figures 118A to 118F Shown is the inhibition of enzyme activity by anti-NA mAbs on NA carrying no (-) or (+) glycan at position 245 transiently expressed in mammalian cells as measured by ELLA.

[0125] Figures 119A to 119D Shown are the inhibition of enzyme activity (IC50 values) by anti-NA mAbs against NA-only pseudotypes carrying N3, N6, N7, N8, or N9 representing highly pathogenic avian influenza A viruses (HPAIV), which have been previously reported to infect humans (Ke et al., 2017; Li et al., 2022; WHO, 2021). Additional data are in Figures 133A to 133C Shown in.

[0126] Figures 120A to 120D Shown are inhibition of NA enzyme activity by anti-NA antibodies against Group 1 (N1) and Group 2 (N2) IAV (A, B) and Yamagata and Victoria lineage IBV (C, D) NA antigens as measured by the MUNANA assay.

[0127] Figures 121A to 121H Figure 2 shows the conservation analysis of key contact residues of the FNI antibody. The average conservation percentage (red line) of key NA contact residues (R118, D151, E227, R292, and R371) for each year from 2000 to 2022 is shown. The number of sequences analyzed each year is indicated (black bars). H1N1, H3N2, and IBV isolates are of human origin, while for H5N1, H7N9, H5N8, and H5N6, viruses from all animal hosts are included.

[0128] Figures 122A to 122E Detailed structural analysis of FNI antibodies bound to NA is shown. Data provided: (A) Static epitope analysis of FNI9:NA (Tanzania / 2010) is depicted as a heat map with the shading scale being MOE kcal / mol energy, and the density map compressing all energies by epitope residue and by paratope residue. The total energy is -230 MOE kcal / mol. The static epitope analysis of FNI17:NA (Tanzania / 2010) is also depicted in the same manner. The total energy is -240 MOE kcal / mol. (B) Dynamic epitope-paratope analysis of FNI9:NA (Tanzania / 2010), which is depicted as in (A), except that the energies are averaged over a total of 11.5 μs of all-atom MD simulations (once every 10 ns) using the same MOE energy analysis as described above for (A). The total energy is -370 MOE kcal / mol. (C) The percent occupancy of the epitope-paratope interaction reflects (in (Inside) Fraction of 11.5 μs MD with contacts present. Total occupancy is 5600 (%). Total occupancy of epitope-paratope interactions for FNI17:NA is 4700 (%). Outlined boxes depict epitope residue-paratope residue contacts present in the FNI9 dynamic paratope analysis but absent in the FNI17 dynamic paratope analysis. (D) Comparison of epitope interaction energies between FNI9 and FNI17, where black stars depict contacts present in FNI9 but not FNI17, and white stars depict contacts present in FNI17 but not FNI9. (E) Comparison of paratope interaction energies between FNI9 and FNI17, where black and white stars are the same as in (D).

[0129] Figure 123 Shown is a list of influenza virus strains and the neutralization EC50s of the indicated anti-NA antibodies.

[0130] Figure 124 Shown is a list of NA antigens from seasonal viruses with or without glycan 245 and with corresponding affinities (KD) measured by SPR to certain FNI antibody Fabs and 1G01 Fab.

[0131] Figures 125A to 125B FNI9-v5 ( Figure 125A ) and FNI9-v8.1( Figure 125B ) In vivo pharmacokinetics of concentration changes over time in SCID tg32 mice over approximately 60 days after administration (reported in μg / ml). The antibody was expressed as a recombinant IgG1m3 with M428L and N434S ("LS", also known as "MLNS") mutations in the Fc.

[0132] Figures 126A to 126E Summarizes the in vivo pharmacokinetic data of FNI9-v5-LS ("FNI9-v5-rIgG1-LS") and FNI9-v8.1-LS ("FNI9-v8.1-rIgG1m3-LS") in SCID tg32 mice. Data for five individual animals are shown.

[0133] Figures 127A to 127C Summarized are the results of tissue cross-reactivity (TCR) studies using FNI9-v8.1 (conjugated to Alexa Fluor 488) against a panel of human tissues, as measured using immunohistochemical staining.

[0134] Figures 128A to 128CShown is the inhibition of neuraminidase enzymatic activity by anti-NA mAbs FNI9-v8.1, FNI17-v19, and FNI19-v3 against NA-only pseudotypes carrying N3, N4, or N5 representing endemic low pathogenic avian influenza A viruses (LPAIVs), as measured by ELLA. 1G01 was also tested as a control antibody.

[0135] Figures 129A to 129F Shown is the inhibition of neuraminidase enzymatic activity by anti-NA mAbs FNI9-v8.1, FNI17-v19, and FNI19-v3 against NA-only pseudotypes carrying N1, N2, N6, or N8 representing endemic low-pathogenic mammalian IAVs circulating in pigs, dogs, and seals, as measured by the MUNANA assay. 1G01 was also tested as a control antibody.

[0136] Figures 130A to 130G Shown is the inhibition of neuraminidase enzymatic activity as measured by the MUNANA assay for a panel of pseudotypes carrying NAs with mutations identified by in vitro resistance studies as capable of reducing, but not abolishing, the binding or activity of FNI mAbs.

[0137] Figures 131A to 131B Shown is the inhibition of neuraminidase enzymatic activity as measured by the MUNANA assay for a panel of pseudotypes carrying NA with mutations identified by deep mutational scanning (DMS) as capable of reducing, but not abolishing, binding or activity of the FNI mAb.

[0138] Figures 132A to 132C The results show that the cells infected with H3N2 A / China Hong Kong / 1 / 68 ( Figure 132A and Figure 132C ) or H1N1 A / Puerto Rico / 8 / 34( Figure 132B ) of BALB / c mice (n=6) from day 0 to day 14 after infection (reported as area under the curve). Figure 132A The prefix "mu" is used to indicate the Figure 132B and Figure 132C ). Anti-NA antibodies included FNI9-v8.1-LS, FNI17-LS, and FNI19-v3-LS, and the anti-HA antibody used was FM08. Antibodies were administered at doses of 0.25 mg / kg or 0.125 mg / kg. Weight loss was also measured in mice pretreated with vehicle control. DETAILED DESCRIPTION

[0139] Provided herein are antibodies and antigen-binding fragments that can bind to various influenza viruses, such as influenza A virus (IAV) and influenza B virus (IBV), and effectively neutralize infections caused by these influenza viruses. Also provided are polynucleotides, vectors, host cells, and related compositions encoding the antibodies and antigen-binding fragments, as well as methods of using the antibodies, nucleic acids, vectors, host cells, and related compositions to treat (e.g., reduce, delay, eliminate, or prevent) influenza virus infection in a subject and / or to manufacture a medicament for treating influenza infection in a subject.

[0140] As taught in the present examples, a number of clonally related antibodies were identified that bind to a variety of IAV and IBV NAs and have neutralizing / inhibitory functions against IAV and IBV viruses. Certain antibodies (including "FNI9") have improved function compared to antibody "1G01" (described by Stadlbauer et al. (Science 366(6464):499-504(2019)). The disclosed antibodies and antigen-binding fragments include variants engineered from the antibody FNI9. In some embodiments, the antibodies or antigen-binding fragments have at least substantially equivalent, equivalent, or improved binding breadth; in vitro production titer; neuraminidase inhibition; and / or neutralization potency compared to FNI9 (or its antigen-binding fragment). In some embodiments, the antibodies or antigen-binding fragments of the present disclosure have size exclusion chromatography (SEC) characteristics with no significant aggregation (<3% high molecular weight species) or fragmentation (<3% low molecular weight species) observed by UHPLC-SEC. Certain variant antibodies disclosed herein (e.g., "FNI9-v8.1") have one or more improved functions compared to the parent antibody FNI9.

[0141] Sequence variants of the antibodies are generated and characterized. Certain disclosed embodiments relate to such antibodies, antigen-binding fragments thereof, and related compositions and uses.

[0142] Before describing the present disclosure in more detail, it may be helpful to understand the present disclosure by providing definitions of certain terms used herein. Additional definitions are set forth throughout the present disclosure.

[0143] In this specification, any concentration range, percentage range, ratio range or integer range should be understood to include the value of any integer in the stated range, and its fraction (such as one tenth and one hundredth of an integer) when appropriate, unless otherwise specified. In addition, any quantitative range related to any physical characteristics such as polymer subunits, size or thickness stated herein should be understood to include any integer in the stated range, unless otherwise specified. As used herein, the term "about" means ± 20% of the indicated range, value or structure, unless otherwise specified. It should be understood that, as used herein, the terms "a" and "an" refer to "one or more (one or more)" in the listed components. The use of alternatives (e.g., "or") should be understood to mean one, two or any combination thereof in the alternatives. As used herein, the terms "include," "have," and "comprise" are used synonymously, and these terms and their variants are intended to be interpreted as non-restrictive.

[0144] “Optional” or “optionally” means that the subsequently described element, component, event or circumstance may or may not occur, and that the description includes instances where the element, component, event or circumstance occurs and instances where it does not.

[0145] In addition, it should be understood that this application discloses individual constructs or groups of constructs derived from various combinations of structures and subunits described herein to the same extent as if each construct or group of constructs were individually set forth. Therefore, the selection of a particular structure or a particular subunit is within the scope of this disclosure.

[0146] The term "consisting essentially of" is not equivalent to "comprising" and refers to specified materials or steps of a claim, or to materials or steps that do not materially affect the basic characteristics of the claimed subject matter. For example, a protein domain, region, module (e.g., a binding domain) or protein "consists essentially of" a particular amino acid sequence when the amino acid sequence of the domain, region, module or protein includes extensions, deletions, mutations, or combinations thereof (e.g., amino acids at the amino or carboxyl termini or between domains) that, in total, account for up to 20% (e.g., up to 15%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, or 1%) of the length of the domain, region, module or protein and do not substantially affect (i.e., do not reduce the activity by more than 50%, such as by no more than 40%, 30%, 25%, 20%, 15%, 10%, 5%, or 1%) the activity of the domain, region, module or protein (e.g., the target binding affinity of the binding protein).

[0147] As used herein, "amino acid" refers to naturally occurring or synthetic amino acids, as well as amino acid analogs and amino acid mimetics that function in a manner similar to naturally occurring amino acids. Naturally occurring amino acids are those encoded by the genetic code, as well as those that are later modified, for example, hydroxyproline, γ-carboxyglutamate, and O-phosphoserine. Amino acid analogs refer to compounds that have the same basic chemical structure as naturally occurring amino acids (i.e., an α-carbon bound to a hydrogen, carboxyl, amino, and R group), for example, homoserine, norleucine, methionine sulfoxide, methionine methylsulfonium. Such analogs have modified R groups (e.g., norleucine) or modified peptide backbones, but retain the same basic chemical structure as naturally occurring amino acids. Amino acid mimetics refer to chemical compounds that have a structure that is different from the general chemical structure of an amino acid, but function in a manner similar to naturally occurring amino acids.

[0148] As used herein, "mutation" refers to a change in the sequence of a nucleic acid molecule or polypeptide molecule compared to a reference or wild-type nucleic acid molecule or polypeptide molecule, respectively. A mutation can cause several different types of changes in the sequence, including substitutions, insertions, or deletions of nucleotides or amino acids.

[0149] "Conservative substitutions" refer to amino acid substitutions that do not significantly affect or change the binding properties of a particular protein. Generally speaking, conservative substitutions are substitutions in which the substituted amino acid residue is replaced with an amino acid residue with a similar side chain. Conservative substitutions include substitutions found in one of the following groups: Group 1: Alanine (Ala or A), Glycine (Gly or G), Serine (Ser or S), Threonine (Thr or T); Group 2: Aspartic acid (Asp or D), Glutamic acid (Glu or Z); Group 3: Asparagine (Asn or N), Glutamine (Gln or Q); Group 4: Arginine (Arg or R), Lysine (Lys or K), Histidine (His or H); Group 5: Isoleucine (Ile or I), Leucine (Leu or L), Methionine (Met or M), Valine (Val or V); and Group 6: Phenylalanine (Phe or F), Tyrosine (Tyr or Y), Tryptophan (Trp or W). Additionally or alternatively, amino acids can be grouped into conservative substitution groups based on similar function, chemical structure, or composition (e.g., acidic, basic, aliphatic, aromatic, or sulfur-containing). For example, for substitution purposes, an aliphatic grouping may include Gly, Ala, Val, Leu, and Ile. Other conservative substitution groups include: sulfur-containing: Met and cysteine ​​(Cys or C); acidic: Asp, Glu, Asn, and Gln; small aliphatic, nonpolar, or slightly polar residues: Ala, Ser, Thr, Pro, and Gly; polar, negatively charged residues and their amides: Asp, Asn, Glu, and Gln; polar, positively charged residues: His, Arg, and Lys; large aliphatic, nonpolar residues: Met, Leu, Ile, Val, and Cys; and large aromatic residues: Phe, Tyr, and Trp. Additional information can be found in Creighton (1984) Proteins, WH Freeman and Company.

[0150] As used herein, "protein" or "polypeptide" refers to a polymer of amino acid residues. Protein applies to naturally occurring amino acid polymers, as well as amino acid polymers in which one or more amino acid residues are artificial chemical mimetics of the corresponding naturally occurring amino acids, and non-naturally occurring amino acid polymers. Variants of the proteins, peptides, and polypeptides of the present disclosure are also contemplated. In certain embodiments, the variant proteins, peptides, and polypeptides comprise or consist of an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 99.9% identical to an amino acid sequence as defined or referenced herein.

[0151] As encoded by a polynucleotide sequence, any polypeptide of the present disclosure (e.g., VH, VL, antibody heavy chain, antibody light chain) may comprise a "signal peptide" (also referred to as a leader sequence, leader peptide or transit peptide). The signal peptide targets the newly synthesized polypeptide to its appropriate location inside or outside the cell. The signal peptide may be removed in whole or in part from the polypeptide during or after localization or secretion is completed. A polypeptide having a signal peptide may be referred to as a "preprotein," and a polypeptide from which its signal peptide has been removed may be referred to as a "mature" protein or polypeptide. In certain embodiments, the antibody or antigen-binding fragment is a mature protein or preprotein.

[0152] "Nucleic acid molecule" or "polynucleotide" or "polynucleic acid" refers to a polymer compound comprising covalently linked nucleotides, which may be composed of natural subunits (e.g., purine or pyrimidine bases) or non-natural subunits (e.g., morpholine rings). Purine bases include adenine, guanine, hypoxanthine, and xanthine, and pyrimidine bases include uracil, thymine, and cytosine. Nucleic acid molecules include: polyribonucleic acid (RNA), which includes mRNA, microRNA, siRNA, viral genomic RNA, and synthetic RNA; and polydeoxyribonucleic acid (DNA, also known as deoxyribonucleic acid), which includes cDNA, genomic DNA, and synthetic DNA, any of which may be single-stranded or double-stranded. If single-stranded, the nucleic acid molecule may be a coding strand or a non-coding (antisense) strand. Nucleic acid molecules encoding an amino acid sequence include all nucleotide sequences encoding the same amino acid sequence. Some versions of the nucleotide sequence may also contain introns to the extent that the introns will be removed by co-transcriptional or post-transcriptional mechanisms. In other words, due to redundancy or degeneracy of the genetic code, or by splicing, different nucleotide sequences can encode the same amino acid sequence.

[0153] In some embodiments, the polynucleotide comprises a modified nucleoside, a cap-1 structure, a cap-2 structure, or any combination thereof. In certain embodiments, the polynucleotide comprises pseudouridine, N6-methyladenosine, 5-methylcytidine, 2-thiouridine, or any combination thereof. In some embodiments, the pseudouridine comprises N1-methylpseudouridine. These features are known in the art and are discussed in, for example, Zhang et al., Front. Immunol., DOI=10.3389 / fimmu.2019.00594 (2019); Eyler et al., PNAS 116(46):23068-23071; DOI:10.1073 / pnas.1821754116 (2019); Nance and Meier, ACS Cent. Sci. 2021, 7, 5, 748-756; doi.org / 10.1021 / acscentsci.lc00197 (2021), and van Hoecke and Roose, J. Translational Med 17:54 (2019); https: / / doi.org / 10.1186 / sl2967-019-1804-8, wherein the modified nucleosides and mRNA features are incorporated herein by reference. Variants of the nucleic acid molecules of the present disclosure are also contemplated. Variant nucleic acid molecules are at least 70%, 75%, 80%, 85%, 90%, preferably 95%, 96%, 97%, 98%, 99% or 99.9% identical to a nucleic acid molecule as defined or referenced herein (i.e., at least 70%, at least 75%, at least 80% or at least 90%, preferably at least 95%, 96%, 97%, 98%, 99% or 99.9% identical), or hybridize to a polynucleotide under stringent hybridization conditions of 0.015 M sodium chloride, 0.0015 M sodium citrate at about 65 to 68° C. or 0.015 M sodium chloride, 0.0015 M sodium citrate and 50% formamide at about 42° C. Variant nucleic acid molecules retain the ability to encode a binding domain thereof having the function described herein, such as binding to a target molecule.

[0154] "Percentage of sequence identity" refers to the relationship between two or more sequences as determined by comparing sequences. The preferred method for determining sequence identity is designed to achieve the best match between the compared sequences. For example, for the purpose of optimal comparison, the sequences are aligned (for example, a gap can be introduced in one or both of the first amino acid or nucleic acid sequence and the second amino acid or nucleic acid sequence for optimal comparison). In addition, for the purpose of comparison, non-homologous sequences can be ignored. Unless otherwise indicated, the percentages of sequence identity mentioned herein are calculated over the length of the reference sequence. Methods for determining sequence identity and similarity can be found in publicly available computer programs. BLAST programs (for example, BLAST2.0, BLASTP, BLASTN or BLASTX) can be used for sequence alignment and identity percentage calculation. The mathematical algorithm used in the BLAST program can be found in Altschul et al., Nucleic Acids Res. 25: 3389-3402, 1997. Other examples include Clustal W, MAFFT, Clustal Omega, AlignMe, Praline, GAP, BESTFIT, Needle (EMBOSS), Stretcher (EMBOSS), GGEARCH2SEQ, Water (EMBOSS), Matcher (EMBOSS), LALIGN, and SSEARCH2SEQ. Global alignment algorithms (such as the Needleman and Wunsch algorithms) can be used to align two sequences over their entire length, maximizing the number of matches and minimizing the number of gaps. Default values ​​can be used.

[0155] To generate a similarity score for two amino acid sequences, a scoring matrix can be used that assigns positive scores to some non-identical amino acids (e.g., conservative amino acid substitutions, amino acids with similar physicochemical properties, and / or amino acids that exhibit frequent substitutions in orthologs, homologs, or paralogs). Non-limiting examples of scoring matrices include PAM30, PAM70, PAM250, BLOSUM45, BLOSUM50, BLOUM62, BLOSUM80, and BLOSUM90.

[0156] In the context of the present disclosure, it is understood that where sequence analysis software is used for analysis, the results of the analysis are based on the referenced program's "default values." "Default values" means any set of values ​​or parameters that are initially loaded when the software is first initialized.

[0157] The term "isolated" means that the material is removed from its original environment (e.g., the natural environment if the material is naturally occurring). For example, a naturally occurring nucleic acid or polypeptide present in a living animal is not isolated, but the same nucleic acid or polypeptide separated from some or all of the coexisting materials in the natural system is isolated. Such nucleic acids can be part of a vector, and / or such nucleic acids or polypeptides can be part of a composition (e.g., a cell lysate) and still be isolated because such vectors or compositions are not part of the natural environment of the nucleic acid or polypeptide. In some embodiments, "isolated" can also describe antibodies, antigen-binding fragments, polynucleotides, vectors, host cells or compositions outside the human body. In certain embodiments, a separated antibody, antigen-binding fragment, polynucleotide, vector, host cell or composition is provided.

[0158] The term "gene" means a segment of DNA or RNA involved in producing a polypeptide chain; in certain contexts, a gene includes regions preceding and following the coding region (e.g., 5' untranslated region (UTR) and 3' UTR) as well as intervening sequences (introns) between individual coding segments (exons).

[0159] "Functional variant" refers to a polypeptide or polynucleotide that is structurally similar or substantially structurally similar to a parent or reference compound of the present disclosure but slightly different in composition (e.g., one base, atom, or functional group is different, added, or removed) such that the polypeptide or encoded polypeptide is capable of performing at least one function of the parent polypeptide with at least 50% efficiency, preferably at least 55%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.9%, or 100% of the activity level of the parent polypeptide. In some embodiments, the encoded polypeptide or polypeptide is capable of performing at least one function of the parent polypeptide with at least 55%, at least 60%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.9%, or at least 100% of the activity level of the parent polypeptide. In other words, when a polypeptide of the present disclosure or a functional variant of the encoded polypeptide performs well in a selected assay, such as an assay for measuring binding affinity (e.g., measuring association (Ka) or dissociation (K D ) constant A functional variant has “similar binding,” “similar affinity,” or “similar activity” when it exhibits no more than a 50% decrease in performance compared to the parent or reference polypeptide in a monoclonal antibody assay (e.g., immunoblotting, immunohistochemistry, or tetramer staining).

[0160] As used herein, "functional portion" or "functional fragment" refers to a polypeptide or polynucleotide comprising only a domain, portion or fragment of a parent or reference compound, and the polypeptide or encoded polypeptide retains at least 50% of the activity associated with the domain, portion or fragment of the parent or reference compound, preferably at least 55%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.9% or 100% of the activity level of the parent polypeptide, or provides a biological benefit (e.g., effector function). In some embodiments, the polypeptide or encoded polypeptide retains at least 55%, at least 60%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or at least 99.9% or at least 100% of the activity level of the parent polypeptide. A "functional portion" or "functional fragment" of a polypeptide of the present disclosure or an encoded polypeptide has "similar binding" or "similar activity" when it exhibits no more than a 50% decrease in performance (preferably no more than 20% or 10%, or no more than a log difference in affinity compared to the parent or reference) in a selected assay compared to the parent or reference polypeptide.

[0161] As used herein, the terms "engineered," "recombinant," or "non-natural" refer to organisms, microorganisms, cells, nucleic acid molecules, or vectors that contain at least one genetic alteration or have been modified by the introduction of exogenous or heterologous nucleic acid molecules, wherein such alteration or modification is introduced by genetic engineering (i.e., human intervention). Genetic alterations include, for example, modifications that introduce expressible nucleic acid molecules encoding functional RNA, proteins, fusion proteins, or enzymes, or other functional disruptions of the genetic material of cells by additions, deletions, substitutions, or other nucleic acid molecules. Additional modifications include, for example, non-coding regulatory regions where the modification alters the expression of a polynucleotide, gene, or operon.

[0162] As used herein, "heterologous" or "non-endogenous" or "exogenous" refers to any gene, protein, compound, nucleic acid molecule, or activity that is not native to the host cell or subject, or any gene, protein, compound, nucleic acid molecule, or activity that is native to the host cell or subject but has been altered. Heterologous, non-endogenous, or exogenous includes genes, proteins, compounds, or nucleic acid molecules that have been mutated or otherwise altered such that the structure, activity, or both differ between the native and altered genes, proteins, compounds, or nucleic acid molecules. In certain embodiments, heterologous, non-endogenous, or exogenous genes, proteins, or nucleic acid molecules (e.g., receptors, ligands, etc.) may not be endogenous to the host cell or subject, and nucleic acids encoding such genes, proteins, or nucleic acid molecules may have been added to the host cell by conjugation, transformation, transfection, electroporation, or the like, where the added nucleic acid molecules may be integrated into the host cell genome or may be present as extrachromosomal genetic material (e.g., as a plasmid or other self-replicating vector). The term "homolog" or "homolog" refers to a gene, protein, compound, nucleic acid molecule, or activity found in or derived from a host cell, species, or strain. For example, a heterologous or exogenous polynucleotide or gene encoding a polypeptide can be homologous to a native polynucleotide or gene and encode a homologous polypeptide or activity, but the polynucleotide or polypeptide can have an altered structure, sequence, expression level, or any combination thereof. The non-endogenous polynucleotide or gene and the encoded polypeptide or activity can be from the same species, a different species, or a combination thereof.

[0163] In certain embodiments, a nucleic acid molecule native to the host cell is considered heterologous to the host cell if it has been altered or mutated, or a nucleic acid molecule native to the host cell is considered heterologous if it has been altered with a heterologous expression control sequence or has been altered with an endogenous expression control sequence not normally associated with the nucleic acid molecule native to the host cell. Additionally, the term "heterologous" can refer to a biological activity that is different, altered, or not endogenous to the host cell. As described herein, more than one heterologous nucleic acid molecule can be introduced into the host cell as separate nucleic acid molecules, as multiple individually controlled genes, as polycistronic nucleic acid molecules, as a single nucleic acid molecule encoding a fusion protein, or any combination thereof.

[0164] As used herein, the term "endogenous" or "native" refers to a polynucleotide, gene, protein, compound, molecule or activity that is normally present in a host cell or subject.

[0165] As used herein, the term "expression" refers to the process by which a polypeptide is produced based on the coding sequence of a nucleic acid molecule (such as a gene). The process may include transcription, post-transcriptional control, post-transcriptional modification, translation, post-translational control, post-translational modification, or any combination thereof. The expressed nucleic acid molecule is typically operably linked to an expression control sequence (e.g., a promoter).

[0166] The term "operably linked" refers to the association of two or more nucleic acid molecules on a single nucleic acid fragment so that the function of one is affected by the other. For example, a promoter is operably linked to a coding sequence when it is capable of affecting the expression of the coding sequence (i.e., the coding sequence is under the transcriptional control of the promoter). "Not linked" means that the related genetic elements are not closely associated with each other and the function of one does not affect the other.

[0167] As described herein, more than one heterologous nucleic acid molecule can be introduced into a host cell as a single nucleic acid molecule, as multiple individually controlled genes, as a polycistronic nucleic acid molecule, as a single nucleic acid molecule encoding a protein (e.g., a heavy chain of an antibody), or any combination thereof. When two or more heterologous nucleic acid molecules are introduced into a host cell, it should be understood that the two or more heterologous nucleic acid molecules can be introduced as a single nucleic acid molecule (e.g., on a single vector), introduced on separate vectors, integrated into the host chromosome at a single site or multiple sites, or any combination thereof. The number of heterologous nucleic acid molecules or protein activities cited refers to the number of encoding nucleic acid molecules or protein activities, not the number of individual nucleic acid molecules introduced into the host cell.

[0168] The term "construct" refers to any polynucleotide comprising a recombinant nucleic acid molecule (or, when the context clearly indicates, a fusion protein of the present disclosure). The (polynucleotide) construct may be present in a vector (e.g., a bacterial vector, a viral vector) or may be integrated into a genome. A "vector" is a nucleic acid molecule capable of transporting another nucleic acid molecule. A vector may be, for example, a plasmid, a cosmid, a virus, an RNA vector, or a linear or circular DNA or RNA molecule that may include a chromosomal, non-chromosomal, semisynthetic or synthetic nucleic acid molecule. The vectors of the present disclosure also include transposon systems (e.g., Sleeping Beauty, see, for example, Geurts et al., Mol. Ther. 8: 108, 2003; Mátés et al., Nat. Genet. 41. 753, 2009). Exemplary vectors are vectors capable of autonomous replication (episomal vectors), vectors capable of delivering polynucleotides to the cell genome (e.g., viral vectors), or vectors capable of expressing the nucleic acid molecule to which they are attached (expression vectors).

[0169] As used herein, "expression vector" or "vector" refers to a DNA construct comprising a nucleic acid molecule that is operably linked to a suitable control sequence that enables expression of the nucleic acid molecule in a suitable host. Such control sequences include a promoter that enables transcription, an optional operator sequence that controls such transcription, a sequence encoding a suitable mRNA ribosome binding site, and a sequence that controls the termination of transcription and translation. The vector can be a plasmid, a phage particle, a virus, or simply a potential genome insert. Once transformed into a suitable host, the vector can replicate and function independently of the host genome, or in some cases, can be integrated into the genome itself or the polynucleotide contained in the vector can be delivered to the genome in the absence of a vector sequence. In this manual, "plasmid," "expression plasmid," "virus," and "vector" are generally used interchangeably.

[0170] The term "introduced," in the context of inserting a nucleic acid molecule into a cell, means "transfection," "transformation," or "transduction" and includes reference to the incorporation of a nucleic acid molecule into a eukaryotic or prokaryotic cell, where the nucleic acid molecule may be incorporated into the genome of the cell (e.g., chromosome, plasmid, plastid, or mitochondrial DNA), converted into an autonomous replicon, or transiently expressed (e.g., transfected mRNA).

[0171] In certain embodiments, the polynucleotides of the present disclosure are operably linked to certain elements of the vector. For example, the polynucleotide sequences required to achieve expression and processing of the coding sequence to which the polynucleotide sequence is linked are operably linked. Expression control sequences may include appropriate transcription initiation, termination, promoter, and enhancer sequences; efficient RNA processing signals, such as splicing and polyadenylation signals; sequences that stabilize cytoplasmic mRNA; sequences that enhance translation efficiency (i.e., Kozak consensus sequences); sequences that enhance protein stability; and sequences that may enhance protein secretion. An expression control sequence is operably linked if it is adjacent to a gene of interest and an expression control sequence that acts in trans or at a distance to control the gene of interest.

[0172] In certain embodiments, the vector comprises a plasmid vector or a viral vector (e.g., a lentiviral vector or a gamma-retroviral vector). Viral vectors include retroviruses; adenoviruses; parvoviruses (e.g., adeno-associated viruses); coronaviruses; negative-strand RNA viruses such as orthomyxoviruses (e.g., influenza viruses), rhabdoviruses (e.g., rabies and vesicular stomatitis viruses), paramyxoviruses (e.g., measles and Sendai viruses); positive-strand RNA viruses such as picornaviruses and alphaviruses; and double-stranded DNA viruses including adenoviruses, herpes viruses (e.g., herpes simplex virus type 1 and type 2, Epstein-Barr virus, cytomegalovirus), and pox viruses (e.g., cowpox, fowlpox, and canarypox). Other viruses include, for example, Norwalk virus, togavirus, flavivirus, reovirus, papovavirus, hepadnavirus, and hepatitis virus. Examples of retroviruses include avian leukosis-sarcoma, mammalian C virus, B virus, D virus, HTLV-BLV groups, lentivirus, foamy virus (Coffin, JM, Retroviridae: The viruses and their replication, in Fundamental Virology, 3rd edition, BN Fields et al., eds., Lippincott-Raven Publishers, Philadelphia, 1996).

[0173] A "retrovirus" is a virus with an RNA genome that is reverse-transcribed into DNA using the enzyme reverse transcriptase, which is then incorporated into the host cell genome. A "gammaretrovirus" refers to a genus of the family Retroviridae. Examples of gammaretroviruses include mouse stem cell virus, murine leukemia virus, feline leukemia virus, feline sarcoma virus, and avian reticuloendotheliosis virus.

[0174] "Lentiviral vectors" include HIV-based lentiviral vectors for gene delivery, which can be integrated or non-integrated, have a relatively large packaging capacity, and can transduce a range of different cell types. Lentiviral vectors are typically generated after transient transfection of three (packaging, envelope, and transfer) or more plasmids into production cells. Similar to HIV, lentiviral vectors enter target cells through the interaction of viral surface glycoproteins with receptors on the cell surface. Upon entry, viral RNA undergoes reverse transcription, which is mediated by the viral reverse transcriptase complex. The product of reverse transcription is double-stranded linear viral DNA, which is a substrate for viral integration into infected cell DNA.

[0175] In certain embodiments, the viral vector can be a gammaretrovirus, e.g., a Moloney murine leukemia virus (MLV)-derived vector. In other embodiments, the viral vector can be a more complex retrovirus-derived vector, e.g., a lentivirus-derived vector. HIV-1-derived vectors fall into this category. Other examples include lentiviral vectors derived from HIV-2, FIV, equine infectious anemia virus, SIV, and Maedi-Visna virus (ovine lentivirus). Methods for using retroviral and lentiviral vectors and packaging cells to transduce mammalian host cells with viral particles containing a transgene are known in the art and have been previously described, for example, in U.S. Patent 8,119,772; Walchli et al., PLoS One 6.327930, 2011; Zhao et al., J. Immunol. 174:4415, 2005; Engels et al., Hum. Gene Ther. 14:1155, 2003; Frecha et al., Mol. Ther. 18:1748, 2010; and Verhoeyen et al., Methods Mol. Biol. 506.97, 2009. Retroviral and lentiviral vector constructs and expression systems are also commercially available. Other viral vectors can also be used for polynucleotide delivery, including DNA viral vectors, including, for example, adenovirus-based vectors and adeno-associated virus (AAV)-based vectors; vectors derived from herpes simplex virus (HSV), including amplicon vectors, replication-defective HSV, and attenuated HSV (Krisky et al., Gene Ther. 5:1517, 1998).

[0176] Other vectors that can be used with the compositions and methods of the present disclosure include vectors derived from baculovirus and alphavirus (Jolly, DJ. 1999. Emerging Viral Vectors, pp. 209-40, in Friedmann T. ed., The Development of Human Gene Therapy. New York: Cold Spring Harbor Lab), or plasmid vectors (such as Sleeping Beauty or other transposon vectors).

[0177] When the viral vector genome comprises multiple polynucleotides to be expressed as separate transcripts in a host cell, the viral vector may further comprise additional sequences between the two (or more) transcripts, thereby allowing bicistronic or polycistronic expression. Examples of such sequences for viral vectors include an internal ribosome entry site (IRES), a furin cleavage site, a viral 2A peptide, or any combination thereof.

[0178] Further described herein are plasmid vectors, including DNA-based antibody- or antigen-binding fragment-encoding plasmid vectors for direct administration to a subject.

[0179] As used herein, the term "host" refers to a target cell or microorganism that is genetically modified with a heterologous nucleic acid molecule to produce a polypeptide of interest (eg, an antibody of the present disclosure).

[0180] Host cells can include any single cell or cell culture that can accept vectors or incorporate nucleic acids or express proteins. The term also encompasses offspring of host cells, whether identical or different in inheritance or phenotype. Suitable host cells can depend on the vector and can include mammalian cells, animal cells, human cells, monkey cells, insect cells, yeast cells, and bacterial cells. These cells can be induced to incorporate vectors or other materials by using viral vectors, conversion via calcium phosphate precipitation, DEAE-dextran, electroporation, microinjection, or other methods. See, for example, Sambrook et al., Molecular Cloning: A Laboratory Manual, 2nd edition (Cold Spring Harbor Laboratory, 1989).

[0181] In the context of influenza infection, "host" refers to a cell or subject infected with influenza.

[0182] As used herein, "antigen" or "Ag" refers to an immunogenic molecule that causes an immune response. This immune response may involve antibody production, activation of specific immunocompetent cells, activation of complement, antibody-dependent cellular toxicity, or any combination thereof. Antigens (immunogenic molecules) can be, for example, peptides, glycopeptides, polypeptides, glycopolypeptides, polynucleotides, polysaccharides, lipids, and the like. It will be apparent that antigens can be synthesized, recombinantly produced, or derived from biological samples. Exemplary biological samples that may contain one or more antigens include tissue samples, fecal samples, cells, biological fluids, or combinations thereof. Antigens can be produced by cells that have been modified or genetically engineered to express antigens. Antigens can also be present in influenza NA antigens, such as in virions, or expressed or presented on the surface of cells infected with influenza.

[0183] The term "epitope" or "antigenic epitope" includes any molecule, structure, amino acid sequence, or protein determinant that is recognized and specifically bound by a cognate binding molecule (such as an immunoglobulin) or other binding molecule, domain, or protein. Epitope determinants typically comprise chemically active surface groupings of molecules such as amino acids or sugar side chains, and may have specific three-dimensional structural characteristics as well as specific charge characteristics. Where the antigen is or comprises a peptide or protein, the epitope may be composed of contiguous amino acids (e.g., a linear epitope), or may be composed of amino acids from different parts or regions of a protein that are brought close together by protein folding (e.g., a discontinuous or conformational epitope), or may be composed of non-contiguous amino acids that are in close proximity regardless of protein folding.

[0184] Antibodies, antigen-binding fragments and compositions

[0185] In one aspect, the present disclosure provides an isolated anti-influenza neuraminidase (NA) antibody or antigen-binding fragment thereof. In certain embodiments, the antibody or antigen-binding fragment is capable of binding to neuraminidase (NA) from: (i) influenza A virus (IAV), wherein the IAV includes Group 1 IAV, Group 2 IAV, or both; and (ii) influenza B virus (IBV).

[0186] In certain embodiments, the antibodies or antigen-binding fragments of the present disclosure associate or associate with NA without significantly associating or associating with any other molecule or component in the sample.

[0187] In certain embodiments, the antibodies or antigen-binding fragments of the present disclosure specifically bind to IAV NA. As used herein, "specific binding" refers to the association or association of an antibody or antigen-binding fragment with an antigen, wherein the affinity or K a (i.e., the equilibrium association constant for a specific binding interaction, expressed in 1 / M) equal to or greater than 10 5 M -1 (It is equal to the association rate of the association reaction [K on ] and dissociation rate [K off ] ratio) without significantly associating or uniting with any other molecule or component in the sample. Alternatively, affinity can be defined as the equilibrium dissociation constant (K) for a specific binding interaction. d ), the unit is M (for example, 10 - 5 M to 10 -13 M). Antibodies can be classified as "high affinity" antibodies or "low affinity" antibodies. "High affinity" antibodies are those that a For at least 10 7 M -1 , at least 10 8 M -1 , at least 109 M -1 , at least 10 10 M -1 , at least 10 11 M -1 , at least 10 12 M -1 or at least 10 13 M -1 "Low affinity" antibodies are those with K a Up to 10 7 M -1 , up to 10 6 M -1 , up to 10 5 M -1 Alternatively, affinity can be defined as the equilibrium dissociation constant (K d ), the unit is M (for example, 10 -5 M to 10 -13 M).

[0188] A variety of assays are known for identifying antibodies of the disclosure that bind to a particular target, and for determining binding domain or binding protein affinity, such as Western blot, ELISA (e.g., direct, indirect, or sandwich), analytical ultracentrifugation, spectroscopy, biolayer interferometry, and surface plasmon resonance. Assays for assessing affinity or apparent affinity or relative affinity are also known.

[0189] In some examples, influenza NA antigens can be expressed recombinantly in host cells (e.g., by transfection) and immunostained (e.g., fixed or fixed and permeabilized) host cells with antibodies and analyzed by flow cytometry (e.g., using a ZE5 cell analyzer). Binding is determined by analyzing the binding using FlowJo software (TreeStar). In some embodiments, positive binding can be defined by differential antibody staining of cells expressing influenza NA versus control (e.g., mock) cells.

[0190] In some embodiments, the antibodies or antigen-binding fragments of the present disclosure bind to influenza NA protein as measured using bio-layer interferometry or by surface plasmon resonance.

[0191] IC50 or EC50 values ​​can be used to describe certain properties of the currently disclosed antibodies or antigen-binding fragments. In certain embodiments, IC50 is the concentration of a composition (e.g., an antibody) that causes half-maximal inhibition of an indicated biological or biochemical function, activity, or response. In certain embodiments, EC50 is the concentration of a composition that provides half-maximal response in an assay. In some embodiments, for example, to describe the ability of a currently disclosed antibody or antigen-binding fragment to neutralize infection caused by influenza, IC50 and EC50 are used interchangeably.

[0192] In certain embodiments, the antibodies of the present disclosure are capable of neutralizing infection caused by influenza. As used herein, a "neutralizing antibody" is an antibody that can neutralize, i.e., prevent, inhibit, reduce, hinder, or interfere with the ability of a pathogen to initiate and / or perpetuate an infection in a host. The terms "neutralizing antibody" and "neutralizing antibody" are used interchangeably herein. In any of the presently disclosed embodiments, the antibody or antigen-binding fragment is capable of preventing and / or neutralizing influenza infection in an in vitro infection model and / or in an in vivo infection animal model and / or in humans.

[0193] In certain embodiments, the antibody or antigen-binding fragment thereof is human, humanized, or chimeric.

[0194] In certain embodiments, (i) Group 1 IAV NA includes N1, N4, N5, and / or N8; and / or (ii) Group 2 IAV NA includes N2, N3, N6, N7, and / or N9. In some embodiments: (i) N1 is N1 from any one or more of the following: A / California / 07 / 2009, A / California / 07 / 2009I223R / H275Y, A / California / 07 / 2009Q250S, A / Swine / Jiangsu / Jiangsu / J004 / 2018, A / Swine / Hebei / 2017, A / Stockholm / 18 / 2007, A / Brisbane / 02 / 2018, A / Michigan / 45 / 2015, A / Mississippi / 3 / 2001, A / Netherlands / 603 / 2009, A / Netherlands / 602 / 2009, A / Vietnam / 1203 / 2004, A / Vietnam / 1203 / 2006. 004S247R, A / Vietnam / 1203 / 2004I223R, A / Vietnam / 1203 / 2004R152I, A / Vietnam / 1203 / 2004D199N, A / G4 / SW / Shandong / 1207 / 2016, A / G4 / SW / Henan / SN13 / 2018, A / Mink / Spain / 2022 and A / New Jersey / 8 / 1976; (ii) N4 from A / Mallard / Netherlands / 30 / 2011; (iii) N5 from A / Waterfowl / Korea / CN5 / 2009; (iv) N8 from A / Harbor Seal / New Hampshire / 179629 / 2011 and A / Chicken / Russia / 3-29 / 2020;(v) N2 is N2 from any one or more of the following: A / Washington / 01 / 2007, A / Hong Kong / 68, A / South Australia / 34 / 2019, A / Switzerland / 8060 / 2017, A / Singapore / INFIMH-16-0019 / 2016, A / Switzerland / 9715293 / 2013, A / Leningrad / 134 / 17 / 57, A / Florida / 4 / 2006, A / Netherlands / 823 / 1992, A / Norway / 466 / 2014, A / Switzerland / 8060 / 2017, A / Texas / 50 / 2012, A / Victoria / 361 / 2011, A / Hong Kong, China / 2671 / 2019, A / Hong Kong, China / 2671 / 2019K431E, A / SW / Mexico / SG1444 / 2011, A / Tanzania / 205 / 2010, A / Aichi Prefecture / 2 / 1968, A / Bilthoven / 21793 / 1972, A / Netherlands / 233 / 1982, A / Shanghai / 11 / 1987, A / Nanchang / 933 / 1995, A / Fukui / 45 / 2004, A / Brisbane / 10 / 2007, A / Tasmania / 503 / 2020, A / Cambodia / 2020, A / Perth / 16 / 2009, A / Kansas / 14 / 2017, A / Pig / Kansas / 2021, A / Dog / Korea / VC378 / 2012 and A / Dog / Indiana / 003018 / 2016; (vi) N3 from A / Canada / rv5 04 / 2004 and A / chicken / Jalisco / PAVX17170 / 2017; (v) N6 is from A / swine / Ontario / 01911 / 1 / 99, A / Ck / Suzhou / j6 / 2019 and A / Hangzhou / 01 / 2021; (vi) N7 is from A / Netherlands / 078 / 03 and A / Ck / 621572 / 03; and / or (vii) N9 is N9 from any one or more of the following: A / Anhui / 2013 and A / Hong Kong, China / 56 / 2015. In certain embodiments, IBV NA is NA from any one or more of the following: B / Lee / 10 / 1940 (ancestor); B / Brisbane / 60 / 2008 (Victoria); B / Malaysia / 2506 / 2004 (Victoria); B / Malaysia / 3120318925 / 2013 (Yamagata); B / Wisconsin / 1 / 2010 (Yamagata); B / Yamanashi / 166 / 1998 (Yamagata); B / Brisbane / 33 / 2008; B / Colorado / 06 / 2017; B / Hubei Wujiang / 158 / 2009; B / Massachusetts / 02 / 2012; B / Netherlands / 234 / 2011; B / Perth / 211 / 2001; B / Phuket / 3073 / 2013; B / Texas / 06 / 2011 (Yamagata);B / Perth / 211 / 2011; B / Hong Kong, China / 05 / 1972; B / Harbin / 7 / 1994 (Victoria); B / Washington / 02 / 2019 (Victoria); B / Victoria / 504 / 2000 (Yamagata); B / Victoria / 2 / 87; B / Victoria / 2 / 87 lineage; B / Yamagata / 16 / 88; and B / Yamagata / 16 / 88 lineage.

[0195] In certain embodiments, the antibody or antigen-binding fragment is capable of binding to each of: (i) Group 1 IAV NA; (ii) Group 2 IAV NA; and (iii) IBV NA with an EC50 of 50 In the range of about 0.1 μg / mL to about 50 μg / mL, or in the range of about 0.1 μg / mL to about 2 μg / mL, or in the range of 0.1 μg / mL to about 10 μg / mL, or in the range of 2 μg / mL to about 10 μg / mL, or in the range of about 0.4 μg / mL to about 50 μg / mL, or in the range of about 0.4 μg / mL to about 2 μg / mL, or in the range of 0.4 μg / mL to about 10 μg / mL, or in the range of 2 μg / mL to about 10 μg / mL, or in the range of 0.4 μg / mL to about 1 μg / mL, or 0.4 μg / mL or less.

[0196] In certain embodiments, the antibody or antigen-binding fragment is capable of: (i) activating an antibody or antigen-binding fragment at an EC in the range of about 0.4 μg / mL to about 50 μg / mL, about 0.4 μg / mL to about 10 μg / mL, about 0.4 μg / mL to about 2 μg / mL, about 2 μg / mL to about 50 μg / mL, about 2 μg / mL to about 10 μg / mL, or about 10 μg / mL to about 50 μg / mL; 50 to Group 1 IAV NA; (ii) at an EC in the range of about 0.4 μg / mL to about 50 μg / mL, or about 0.4 μg / mL to about 10 μg / mL, or about 0.4 μg / mL to about 2 μg / mL, or about 2 μg / mL to about 50 μg / mL, or about 2 μg / mL to about 10 μg / mL, or about 10 μg / mL to about 50 μg / mL. 50and / or (iii) at an EC of about 0.4 μg / mL, or in the range of about 0.1 μg / mL to about 1.9 μg / mL, or about 0.1 μg / mL to about 1.5 μg / mL, or about 0.1 μg / mL to about 1.0 μg / mL, or about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 In further embodiments, the antibody or antigen-binding fragment is capable of: (i) binding to IBV NA at an EC of about 0.4 μg / mL, or in the range of about 0.4 μg / mL to about 50 μg / mL, or in the range of about 0.1 μg / mL to about 1.9 μg / mL, or in the range of about 0.1 μg / mL to about 1.5 μg / mL, or in the range of about 0.1 μg / mL to about 1.0 μg / mL, or about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 (ii) binds to N1 at an EC of about 0.4 μg / mL, or at about 0.1 μg / mL to about 1.9 μg / mL, or at about 0.1 μg / mL to about 1.5 μg / mL, or at about 0.1 μg / mL to about 1.0 μg / mL, or at about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 binds to N4; (iii) at an EC in the range of about 0.4 μg / mL to about 2 μg / mL 50 Binds to N5; (iv) with an EC of approximately 50 μg / mL 50 (v) binds to N8 at an EC in the range of about 0.4 μg / mL to about 20 μg / mL, or about 0.4 μg / mL to about 10 μg / mL, or about 0.4 μg / mL to about 2 μg / mL, about 1 μg / mL to about 10 μg / mL, or about 1 μg / mL to about 20 μg / mL, or about 1 μg / mL to about 5 μg / mL, or about 1 μg / mL, 2 μg / mL, 3 μg / mL, 4 μg / mL, 5 μg / mL, 6 μg / mL, 7 μg / mL, 8 μg / mL, 9 μg / mL, 10 μg / mL, 15 μg / mL, or 20 μg / mL. 50(vi) binds to N2 at an EC of about 0.4 μg / mL, or at about 0.1 μg / mL to about 1.9 μg / mL, or at about 0.1 μg / mL to about 1.5 μg / mL, or at about 0.1 μg / mL to about 1.0 μg / mL, or at about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 (vii) binds to N3 at an EC of about 0.4 μg / mL, or in the range of about 0.1 μg / mL to about 1.9 μg / mL, or about 0.1 μg / mL to about 1.5 μg / mL, or about 0.1 μg / mL to about 1.0 μg / mL, or about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 binds to N6; (viii) at an EC in the range of about 2 μg / mL to about 50 μg / mL 50 (ix) binds to N7 at an EC of about 0.4 μg / mL, or at about 0.1 μg / mL to about 1.9 μg / mL, or at about 0.1 μg / mL to about 1.5 μg / mL, or at about 0.1 μg / mL to about 1.0 μg / mL, or at about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 and / or (xi) binds to N9 at an EC of about 0.4 μg / mL, or in the range of about 0.1 μg / mL to about 1.9 μg / mL, or about 0.1 μg / mL to about 1.5 μg / mL, or about 0.1 μg / mL to about 1.0 μg / mL, or about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 Binds to IBV NA.

[0197] In certain embodiments, the antibody or antigen-binding fragment is capable of: (i) performing an immunoblotting assay at an EC of about 0.4 μg / mL, or in the range of about 0.1 μg / mL to about 1.9 μg / mL, or about 0.1 μg / mL to about 1.5 μg / mL, or about 0.1 μg / mL to about 1.0 μg / mL, or about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 Combined with one or more of the following: N1 A / California / 07 / 2009, N1 A / California / 07 / 2009I223R / H275Y, N1 A / Swine / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu / Jiangsu A / Anhui / 1 / 2013, B / Lee / 10 / 1940 (ancestor), B / Brisbane / 60 / 2008 (Victoria), B / Malaysia / 2506 / 2004 (Victoria), B / Malaysia / 3120318925 / 2013 (Yamagata), B / Wisconsin / 1 / 2010 (Yamagata), and B / Yamanashi / 166 / 1998 (Yamagata); (ii) at an EC of about 2 μg / mL or in the range of about 2 μg / mL to about 10 μg / mL. 50 Binds to N5 A / Waterbird / Korea / CN5 / 2009; (iii) with an EC of approximately 50 μg / mL 50 binds to N8 A / Harbor Seal / New Hampshire / 179629 / 2011; (iv) at an EC ranging from about 2 μg / mL to about 10 μg / mL 50 binds to N2 A / Washington / 01 / 2007; (v) at an EC ranging from about 2 μg / mL to about 50 μg / mL 50 binds to N7 A / Netherlands / 078 / 03; (vi) with an EC ranging from about 0.4 μg / mL to about 50 μg / mL 50 binds to N2 A / South Australia / 34 / 2019; (vii) at an EC ranging from about 9.5 μg / mL to about 3.8 μg / mL 50 binds to N2 A / Switzerland / 8060 / 2017; (viii) with an EC ranging from about 18.4 μg / mL to about 2.2 μg / mL50 binds to N2 A / Singapore / INFIMH-16-0019 / 2016; (iv) at an EC ranging from about 1.6 μg / mL to about 1.2 μg / mL 50 in combination with N2 A / Switzerland / 9715293 / 2013; and / or (v) at an EC in the range of about 0.4 μg / mL to about 50 μg / mL, or about 0.4 μg / mL, about 2 μg / mL, about 10 μg / mL, or about 50 μg / mL. 50 Binding to N1 A / Swine / Jiangsu / Jiangsu / J004 / 2018. In certain embodiments, NA is expressed on the surface of a host cell (e.g., a CHO cell), and binding to NA is determined by flow cytometry.

[0198] In certain embodiments, the antibody or antigen-binding fragment is capable of binding to NA with a KD of less than 1.0E-12M, less than 1.0E-11M, less than 1.0E-11M, or 1.0E-12M or less, 1.0E-11M or less, or 1.0E-10 or less, or a KD between 1.0E-10 and 1.0E-13, or a KD between 1.0E-11 and 1.0E-13, wherein optionally, the binding is assessed by biolayer interferometry (BLI).

[0199] In certain embodiments, NA is N1, N2, and / or N9. In certain embodiments, the antibody or antigen-binding fragment is capable of binding to: (1) an NA epitope comprising any one or more of the following amino acids (N1 NA numbering): R368, R293, E228, E344, S247, D198, D151, R118; and / or (2) an NA epitope comprising any one or more of the following amino acids (N2 NA numbering): R371, R292, E227, E344, S247, D198, D151, R118. It should be understood that the antibodies and antigen-binding fragments may also bind to influenza neuraminidase that may not follow the N1 or N2 amino acid numbering convention; the amino acids of these epitopes may correspond to the N1 or N2 amino acid residues indicated herein, such as by the same amino acid residue at an equivalent (e.g., by arrangement, 3-D structure, conservation, or a combination of these) but differently numbered position in the NA. Thus, reference to an N1 or N2 number will be understood to refer to the amino acid corresponding to the recited amino acid. An example showing N1 and N2 position numbering is provided in Table 3 (using H1N1_California.07.2009 and H3N2_New York.392.2004).

[0200] In certain embodiments, the antibody or antigen-binding fragment is capable of binding to: (1) a NA epitope comprising amino acids R368, R293, E228, D151, and R118 (N1 NA numbering); and / or (2) a NA epitope comprising amino acids R371, R292, E227, D151, and R118 (N2 NA numbering). In certain embodiments, the antibody or antigen-binding fragment is capable of binding to an epitope contained in or comprising the NA active site (as described herein, the NA active site comprises functional amino acids that form the catalytic core and directly contact sialic acid, and structural amino acids that form the framework of the active site), wherein optionally, the NA active site comprises the following amino acids (N2 numbering): R118, D151, R152, R224, E276, R292, R371, Y406, E119, R156, W178, S179, D / N198, I222, E227, H274, E277, D293, E425. In certain embodiments, R118, D151, R152, R224, E276, R292, R371, and Y406 form the catalytic core and directly contact sialic acid. In certain embodiments, E119, R156, W178, S179, D / N198, 1222, E227, H274, E277, D293, and E425 form the active site framework.

[0201] In certain embodiments, the epitope comprises or further comprises any one or more of the following NA amino acids (N2 numbering): E344, E227, S247, and D198. In certain embodiments, the antibody or antigen-binding fragment is capable of binding to NA comprising an S245N amino acid mutation and / or an E221D amino acid mutation (N2 numbering).

[0202] In certain embodiments, the NA comprises IBV NA. In certain embodiments, the antibody or antigen-binding fragment is capable of binding to an IBV NA epitope comprising any one or more of the following amino acids (IBV numbering; e.g., for FluB Victoria and FluB Yamagata): R116, D149, E226, R292, and R374. In some embodiments, the epitope comprises amino acids R116, D149, E226, R292, and R374.

[0203] In certain embodiments, the antibodies or antigen-binding fragments are capable of inhibiting the sialidase activity of: (i) IAV NA, wherein the IAV NA comprises Group 1 IAV NA, Group 2 IAV NA, or both, and / or (ii) IBV NA in an in vitro infection model, an in vivo infection animal model, and / or a human. In further embodiments: (i) Group 1 IAV NA comprises H1N1 and / or H5N1; (ii) Group 2 IAV NA comprises H3N2 and / or H7N9; and / or (iii) IBV NA includes one or more of the following: B / Lee / 10 / 1940 (ancestor); B / Hong Kong, China / 05 / 1972; B / Taiwan, China / 2 / 1962 (ancestor); B / Brisbane / 33 / 2008 (Victoria); B / Brisbane / 60 / 2008 (Victoria); B / Malaysia / 2506 / 2004 (Victoria); B / New York / 1056 / 2003 (Victoria); B / Florida / 4 / 2006 (Yamagata); B / Jiangsu / 10 / 2003 (Yamagata); B / Texas / 06 / 2011 ( Yamagata Prefecture); B / Perth / 211 / 2011; B / Harbin / 7 / 1994 (Victoria); B / Colorado / 06 / 2017 (Victoria); B / Washington / 02 / 2019 (Victoria); B / Perth / 211 / 2001 (Yamagata Prefecture); B / Hubei Wujiagang / 158 / 2009 (Yamagata Prefecture); B / Wisconsin / 01 / 2010 (Yamagata Prefecture); B / Massachusetts / 02 / 2012 (Yamagata Prefecture); B / Phuket / 3073 / 2013 (Yamagata Prefecture); and B / Victoria / 504 / 2000 (Yamagata Prefecture).

[0204] In certain embodiments, the antibody or antigen-binding fragment is capable of inhibiting the sialidase activity of Group 1 IAV NA, Group 2 IAV NA and / or IBV NA with an IC50 between about 0.0008 μg / mL to about 4 μg / mL, about 0.0008 μg / mL to about 3 μg / mL, about 0.0008 μg / mL to about 2 μg / mL, about 0.0008 μg / mL to about 1 μg / mL, about 0.0008 μg / mL to about 0.9 μg / mL, about 0.0008 μg / mL to about 0.8 μg / mL, about 0.0008 μg / mL to about 0.7 μg / mL, about 0.0008 μg / mL to about 0.6 μg / mL, about 0.0008 μg / mL to about 0.5 μg / mL, about 0.0008 μg / mL to about 0.4 μg / mL. L, about 0.0008 μg / mL to about 0.3 μg / mL, about 0.0008 μg / mL to about 0.2 μg / mL, about 0.0008 μg / mL to about 0.1 μg / mL, about 0.0008 μg / mL to about 0.09 μg / mL, about 0.0008 μg / mL to about 0.08 μg / mL, about 0.0008 μg / mL to about 0.07 μg / mL, about 0.0008 μg / mL to about 0.06 μg / mL, about 0.0008 μg / mL to about 0.05 μg / mL, about 0.0008 μg / mL to about 0.04 μg / mL, about 0.0008 μg / mL to about 0.03 μg / mL mL, about 0.0008 μg / mL to about 0.02 μg / mL, about 0.0008 μg / mL to about 0.01 μg / mL, 0.002 μg / mL to about 4 μg / mL, about 0.001 μg / mL to 50 μg / mL, about 0.1 μg / mL to about 30 μg / mL, about 0.1 μg / mL to about 20 μg / mL, about 0.1 μg / mL to about 10 μg / mL, about 0.1 μg / mL to about 9 μg / mL, about 0.1 μg / mL to about 8 μg / mL, about 0.1 μg / mL to about 7 μg / mL, about 0.1 μg / mL to about 6 μg / mL, about 0.1 μg / mL to about 5 μg / mL , about 0.1 μg / mL to about 4 μg / mL, about 0.1 μg / mL to about 3 μg / mL, about 0.1 μg / mL to about 2 μg / mL, about 0.1 μg / mL to about 1 μg / mL, about 0.1 μg / mL to about 0.9 μg / mL, about 0.1 μg / mL to about 0.8 μg / mL, about 0.1 μg / mL to about 0.7 μg / mL, about 0.1 μg / mL to about 0.6 μg / mL, about 0.1 μg / mL to about 0.5 μg / mL, about 0.1 μg / mL to about 0.4 μg / mL, about 0.1 μg / mL to about 0.3 μg / mL, about 0.1 μg / mL to about 0.2 μg / mL, about 0.8 μg / mL to about 30 μg / mL, about 0.8 μg / mL to about 20 μg / mL, about 0.8 μg / mL to about 10 μg / mL, about 0.8 μg / mL to about 9 μg / mL, about 0.8 μg / mL to about 8 μg / mL, about 0.8 μg / mL to about 7 μg / mL, about 0.8 μg / mL to about 6 μg / mL, about 0.8 μg / mL to about 5 μg / mL, about 0.8 μg / mL to about 10 μg / mL. / mL to about 4 μg / mL, about 0.8 μg / mL to about 3 μg / mL, about 0.8 μg / mL to about 2 μg / mL, about 0.8 μg / mL to about 1 μg / mL, or about 0.1 μg / mL, about 0.2 μg / mL, about 0.3 μg / mL, about 0.4 μg / mL, about 0.5 μg / mL, about 0.6 μg / mL, about 0.7 μg / mL, about 0.8 μg / mL. L, about 0.9 μg / mL, about 1.0 μg / mL, about 1.5 μg / mL, about 2.0 μg / mL, about 2.5 μg / mL, about 3.0 μg / mL, about 3.5 μg / mL, about 4.0 μg / mL, about 4.5 μg / mL, about 5.0 μg / mL, about 5.5 μg / mL, about 6.0 μg / mL, about 6.5 μg / mL, about 7.0 μg / mL, about 7.5 μg / mL L, about 8.0 μg / mL, about 8.5 μg / mL, about 9.0 μg / mL, about 10 μg / mL, about 11 μg / mL, about 12 μg / mL, about 13 μg / mL, about 14 μg / mL, about 15 μg / mL, about 16 μg / mL, about 17 μg / mL, about 18 μg / mL, about 19 μg / mL, about 20 μg / mL, about 25 μg / mL and / or about 30 μg / mL. In further embodiments, the antibody or antigen-binding fragment is capable of inhibiting the NA sialidase activity of one or more Group 1 and / or Group 2 IAVs and / or one or more IBVs with an IC50 between about 0.00001 μg / ml and about 25 μg / ml, or about 0.0001 μg / ml and about 10 μg / ml, or about 0.0001 μg / ml and about 1 μg / ml, or about 0.0001 μg / ml and about 0.1 μg / ml, or about 0.0001 μg / ml and about 0.01 μg / ml, or about 0.0001 μg / ml to about 0.001 μg / ml, or about 0.0001 μg / ml to about 0.0001 μg / ml, or about 0.0001 μg / ml to about 25 μg / ml, or about 0.0001 μg / ml to about 10 μg / ml, or about 0.0001 μg / ml to about 1 μg / ml, or about 0.0001 μg / ml to about 0.1 μg / ml, or about 0.0001 μg / ml to about 0.01 μg / ml, or about 0.001 μg / ml to about 25 μg / ml, or about 0.0.001 μg / ml to about 10 μg / ml, or about 0.001 μg / ml to about 1 μg / ml, or about 0.001 μg / ml to about 0.1 μg / ml, or about 0.001 μg / ml to about 0.01 μg / ml, or about 0.01 μg / ml to about 25 μg / ml, or about 0.01 μg / ml to about 10 μg / ml, or about 0.01 μg / ml to about 1 μg / ml, or about 0.01 μg / ml to about 0.1 μg / ml, or about 1 μg / ml to about 25 μg / ml, or about 1 μg / ml to about 10 μg / ml, or about 1 μg / ml, 1.5 μg / ml, or about 1 μg / ml. l, 2μg / ml, 2.5μg / ml, 3μg / ml, 3.5μg / ml, 4μg / ml, 4.5μg / ml, 5μg / ml, 5.5μg / ml, 6μg / ml, 6.5μg / ml, 7μg / ml, 7.5μg / ml, 8μg / ml, 8.5μg / ml, 9μg / ml, 9.5μg / ml, 10μg / ml, 10.5μg / ml, 11μg / ml, 11.5μg / ml, 12μg / ml, 12.5μg / ml, 13μg / ml, 13.5μg / ml, 14μg / ml, 14.5μg / ml or 15μg / ml. .

[0205] In certain embodiments, antibodies or antigen binding fragments can activate human FcγRIIIa. In other embodiments, activation is determined using host cells (optionally, Jurkat cells) after incubation (for example, 23 hours) with target cells (for example, A549 cells) infected with IAV, the host cells comprising: (i) human FcγRIIIa (optionally, F158 alleles); and (ii) NFAT expression control sequences, which are operably linked to sequences encoding reporter genes such as luciferase reporter genes. In other embodiments, activation is determined after incubation (optionally, about 23 hours) with target cells infected with H1N1IAV, wherein optionally, H1N1 IAV is A / PR8 / 34, and / or wherein optionally, the infection multiplicity (MOI) of the infection is 6.

[0206] In certain embodiments, the antibodies or antigen-binding fragments are capable of neutralizing infection caused by IAV and / or IBV. In certain embodiments, the IAV and / or IBV are resistant to antiviral drugs, wherein optionally, the antiviral drug is oseltamivir. In certain embodiments, the IAV comprises an N1 NA comprising the following amino acid mutations: H275Y; E119D + H275Y; S247N + H275Y; I222V; and / or N294S, wherein optionally, the IAV comprises CA09 or A / Aichi Prefecture. In certain embodiments, the IAV comprises an N2 NA comprising the amino acid mutations E119V, Q136K, and / or R292K. In certain embodiments, the IAV comprises an N1 NA comprising the following amino acid mutations: S247R, I223R, R152I, D199N and / or Q250S, wherein optionally, the IAV comprises A / Vietnam / 1203 / 2004 or A / California / 7 / 2009. In certain embodiments, the IAV comprises an N2 NA comprising the amino acid mutation K431E, wherein optionally, the IAV comprises A / Hong Kong / 2671 / 2019.

[0207] In certain embodiments, the antibodies or antigen-binding fragments are capable of treating and / or preventing (i) IAV infection and / or (ii) IBV infection in a subject. In certain embodiments, the antibodies or antigen-binding fragments are capable of treating and / or reducing infection caused by: (i) H1N1 virus, wherein optionally, the H1N1 virus includes A / PR8 / 34; and / or (ii) H3N2 virus, wherein optionally, the H3N2 virus optionally includes A / China Hong Kong / 68. In certain embodiments, after administration of an effective amount of the antibody or antigen-binding fragment, the antibody or antigen-binding fragment is capable of preventing weight loss in a subject infected with IAV and / or IBV, optionally for (i) up to 15 days or (ii) for more than 15 days.

[0208] In certain embodiments, the antibody or antigen-binding fragment is capable of preventing greater than 10% weight loss in a subject with IAV infection and / or IBV infection as determined by reference to the subject's weight immediately prior to the IAV infection and / or IBV infection.

[0209] In certain embodiments, the antibodies or antigen-binding fragments are capable of prolonging the survival of a subject having an IAV infection and / or an IBV infection.

[0210] In certain embodiments, the in vivo half-life of the antibody or antigen-binding fragment in a mouse (e.g., a tg32 mouse) is: (i) in the range of about 10 days to about 14 days, about 10.2 days to about 13.8 days, about 10.5 days to about 13.5 days, about 11 days to about 13 days, about 11.5 days to about 12.5 days, between 10 days and 14 days, or between 10.5 days and 13.5 days, or between 11 days and 13 days, or about 10.0 days, 10.1 days, 10.2 days, 10.3 days, 10.4 days, 10.6 days, 10.7 days, 10.8 days, 10.9 days, 10.10 days, 10.11 days, 10.12 days, 10.13 days, 10.14 days, 10.15 days, 10.16 days, 10.17 days, 10.18 days, 10.19 days, 10.20 days, 10.21 days, 10.22 days, 10.23 days, 10.24 days, 10.25 days, 10.26 days, 10.27 days, 10.28 days, 10.29 days, 10.30 days, 10.31 days, 10.32 days, 10.33 days, 10.34 days, 10.35 days, 10.36 days, 10.37 days, 10.38 days, 10.39 days, 10.40 days, 10.41 days, 10.42 days, 10.43 days, 10.44 days, 10.45 days, 1 .5 days, 10.6 days, 10.7 days, 10.8 days, 10.9 days, 11.0 days, 11.1 days, 11.2 days, 11.3 days, 11.4 days, 11.5 days, 11.6 days, 11.7 days, 11.8 days, 11.9 days, 12.0 days, 12.1 days, 12.2 days, 12.3 days, 12.4 days, 12.5 days, 12.6 days, 12.7 days, 12.8 days, 12.9 days, 13.0 days, 13.1 days, 13.2 days, 13.3 days, 13.4 days, 13.5 days, 13.6 or (ii) within the range of about 12 days to about 16 days, about 12.5 days to 15.5 days, about 13 days to 15 days, about 13.5 days to about 14.5 days, or between 12 days and 16 days, or between 13 days and 15 days, or between 13.5 days and 14.5 days, or about 12.0 days, 12.1 days, 12.2 days, 12.3 days, 12.4 days, 12.5 days, 12.6 days, 12.7 days, 12.8 days, 12.9 days, or about 13.5 days, 13.7 days, 13.8 days, 13.9 days, or 14.0 days. days, 13.0 days, 13.1 days, 13.2 days, 13.3 days, 13.4 days, 13.5 days, 1.36 days, 13.7 days, 13.8 days, 13.9 days, 14.0 days, 14.1 days, 14.2 days, 14.3 days, 14.4 days, 14.5 days, 14.6 days, 14.7 days, 14.8 days, 14.9 days, 15.0 days, 15.1 days, 15.2 days, 15.3 days, 15.4 days, 15.5 days, 1.56 days, 15.7 days, 15.8 days, 15.9 days or 16.0 days.

[0211] Unless explicitly defined in different ways herein, the terms understood by those skilled in the art of antibody technology are each given the existing meaning in this area.For example, the term "antibody" refers to a complete antibody comprising at least two heavy (H) chains and two light (L) chains interconnected by a disulfide bond, and any antigen-binding portion thereof or fragment thereof, which has or retains the ability to be combined with the antigen target molecule identified by the complete antibody, such as scFv, Fab or Fab'2 fragment. Therefore, the term "antibody" is used in the broadest sense herein and includes polyclonal and monoclonal antibodies, including complete antibodies and their functional (antigen binding) antibody fragments, including fragment antigen binding (Fab) fragments, F (ab') 2 fragments, Fab' fragments, Fv fragments, recombinant IgG (rIgG) fragments, single-chain antibody fragments, including single-chain variable fragments (scFv) and single-domain antibodies (for example, sdAb, sdFv, nanobody) fragments. The term encompasses genetically engineered and / or otherwise modified immunoglobulin forms, such as intrabodies, peptibodies, chimeric antibodies, fully human antibodies, humanized antibodies and heteroconjugated antibodies, multispecific (e.g., bispecific) antibodies, diabodies, triabodies, tetrabodies, tandem double scFvs and tandem three scFvs. Unless otherwise indicated, the term "antibody" should be understood to encompass functional antibody fragments thereof. The term also encompasses complete or full-length antibodies, including antibodies of any class or subclass, including IgG and its subclasses (IgG1, IgG2, IgG3, IgG4), IgM, IgE, IgA and IgD.

[0212] The term "V L ” or “VL” and “V H" or "VH" refer to the variable binding region from the antibody light chain and antibody heavy chain, respectively. In certain embodiments, the VL is of the kappa (κ) class (also referred to herein as "VK"). In certain embodiments, the VL is of the lambda (λ) class. The variable binding region includes discrete, well-defined subregions called "complementarity determining regions" (CDRs) and "framework regions" (FRs). The terms "complementarity determining regions" and "CDRs" are synonymous with "hypervariable regions" or "HVRs" and refer to amino acid sequences within the variable region of an antibody that, in general, collectively confer antigen specificity and / or binding affinity to the antibody, wherein consecutive CDRs (i.e., CDR1 and CDR2, CDR2 and CDR3) are separated from each other in the primary structure by framework regions. Each Each variable region has three CDRs (HCDR1, HCDR2, HCDR3; LCDR1, LCDR2, LCDR3; also referred to as CDRH and CDRL, respectively). In certain embodiments, the antibody VH comprises the following four FRs and three CDRs: FR1-HCDR1-FR2-HCDR2-FR3-HCDR3-FR4; and the antibody VL comprises the following four FRs and three CDRs: FR1-LCDR1-FR2-LCDR2-FR3-LCDR3-FR4. Generally speaking, the VH and VL form an antigen binding site together through their corresponding CDRs. In certain embodiments, one or more CDRs do not contact the antigen and / or do not contribute energetically to antigen binding.

[0213] As used herein, a "variant" of a CDR refers to a functional variant of a CDR sequence having up to 1 to 3 amino acid substitutions (eg, conservative or non-conservative substitutions), deletions, or a combination thereof.

[0214] The numbering of the CDRs and framework regions may be according to any known method or scheme, such as the Kabat, Chothia, EU, IMGT, Contact, North, Martin, and Aho numbering schemes (see, e.g., Kabat et al., "Sequences of Proteins of Immunological Interest," US Dept. Health and Human Services, Public Health Service National Institutes of Health, 1991, 5th ed.; Chothia and Lesk, J. Mol. Biol. 196:901-917 (1987)); Lefranc et al., Dev. Comp. Immunol. 27:55, 2003; Honegger and Plückthun, J. Mol. Biol. 309:657-670 (2001); North et al., J Mol Biol. 310:667-671 (2002); Biol. (2011) 706: 228-56; doi: 10.1016 / j.jmb.2010.10.030; Abhinandan and Martin, Mol Immunol. (2008) 45: 3832-9. 10.1016 / j.molimm.2008.05.022). The antibody and CDR numbering systems of these references are incorporated herein by reference. Antigen Receptor Numbering and Receptor Classification (ANARCI) software tool (2016, Bioinformatics 15:298-300) annotate equivalent residue positions and compare equivalent residue positions of different molecules. Thus, identification of the CDRs of the exemplary variable domain (VH or VL) sequences as provided herein according to one numbering scheme does not exclude antibodies comprising CDRs of the same variable domain as determined using a different numbering scheme. To analyze sequences according to IMGT, use imgt.org / IMGTindex / V-QUEST.php and imgt.org / IMGT_vquest / input.

[0215] In certain embodiments, the antibodies or antigen-binding fragments of the present disclosure comprise CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3, wherein each CDR is independently selected from the corresponding CDR of the NA-specific antibodies provided in Table 1 and / or Table 2. That is, all combinations of CDRs from the NA-specific antibodies provided in Table 1 and / or Table 2 are contemplated.

[0216] In some embodiments, the CDRs are numbered according to the IMGT method.

[0217] The term "CL" refers to "immunoglobulin light chain constant region" or "light chain constant region", i.e., the constant region from the antibody light chain. The term "CH" refers to "immunoglobulin heavy chain constant region" or "heavy chain constant region", which can be further divided into CH1, CH2 and CH3 (IgA, IgD, IgG) or CH1, CH2, CH3 and CH4 domains (IgE, IgM) according to the antibody isotype. The Fc region of the antibody heavy chain is further described herein. In any of the embodiments currently disclosed, the antibodies or antigen-binding fragments of the present disclosure comprise any one or more of CL, CH1, CH2 and CH3. In any of the embodiments currently disclosed, the antibodies or antigen-binding fragments of the present disclosure may comprise any one or more of CL, CH1, CH2 and CH3. In certain embodiments, CL comprises an amino acid sequence that is 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical (or similar) to the amino acid sequence of SEQ ID NO.: 35. In certain embodiments, CH1-CH2-CH3 comprises an amino acid sequence that is 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical (or similar) to the amino acid sequence of any one of SEQ ID NOs.: 34, 35, 38, 70 and 74 to 95. It will be appreciated that, for example, production in mammalian cell lines can remove one or more C-terminal lysines of the antibody heavy chain (see, e.g., Liu et al., mAbs 6(5): 1145-1154 (2014)). Thus, the antibodies or antigen-binding fragments of the present disclosure may comprise a heavy chain, CH1-CH3, CH3, or Fc polypeptide, wherein a C-terminal lysine residue is present or absent; in other words, embodiments in which the C-terminal residue of the heavy chain, CH1-CH3, or Fc polypeptide is not lysine, as well as embodiments in which lysine is the C-terminal residue, are encompassed. In certain embodiments, a composition comprises a plurality of antibodies and / or antigen-binding fragments of the present disclosure, wherein one or more antibodies or antigen-binding fragments do not comprise a lysine residue at the C-terminus of a heavy chain, CH1-CH3, or Fc polypeptide, and wherein one or more antibodies or antigen-binding fragments comprise a lysine residue at the C-terminus of a heavy chain, CH1-CH3, or Fc polypeptide.

[0218] In some embodiments, the antibodies or antigen-binding fragments of the present disclosure may comprise a heavy chain, CH1-CH3, CH3 or Fc polypeptide with or without a C-terminal glycine-lysine sequence (e.g., corresponding to the last two amino acids of SEQ ID NO.: 95).

[0219] "Fab" (antigen binding fragment) is the part of an antibody that binds to an antigen and comprises the variable region of the heavy chain and the CH1 connected to a light chain by an interchain disulfide bond. Each Fab fragment is monovalent with respect to antigen binding, i.e., it has a single antigen binding site. Pepsin treatment of an antibody produces a single large F(ab')2 fragment, which roughly corresponds to two disulfide-linked Fab fragments with divalent antigen binding activity and is still able to cross-link antigen. Fab and F(ab')2 are both examples of "antigen binding fragments." Fab' fragments differ from Fab fragments in having several additional residues at the carboxyl terminus of the CH1 domain, including one or more cysteines from the antibody hinge region. Fab'-SH is herein the designation for Fab' in which the cysteine ​​residues of the constant domains carry a free sulfhydryl group. F(ab')2 antibody fragments were originally produced as pairs of Fab' fragments with hinge cysteines between them. Other chemical couplings of antibody fragments are also known.

[0220] Fab fragments can be connected, for example, by peptide linkers to form single-chain Fab, also referred to herein as "scFab". In these embodiments, the interchain disulfide bonds present in natural Fab may not be present, and the linker is used in whole or in part to link or connect the Fab fragments in a single polypeptide chain. The heavy chain-derived Fab fragment (e.g., comprising, consisting of, or essentially consisting of VH+CH1 or "Fd") and the light chain-derived Fab fragment (e.g., comprising, consisting of, or essentially consisting of VL+CL) can be connected in any arrangement to form scFab. For example, scFab can be arranged in the N-terminal to C-terminal direction according to (heavy chain Fab fragment-linker-light chain Fab fragment) or (light chain Fab fragment-linker-heavy chain Fab fragment). Peptide linkers and exemplary linker sequences for scFab are discussed in further detail herein.

[0221] "Fv" is a small antibody fragment that contains a complete antigen recognition and antigen binding site. The fragment generally consists of a dimer of one heavy-chain variable region domain and one light-chain variable region domain in tight, non-covalent association. However, even a single variable domain (or half of an Fv containing only three CDRs specific for an antigen) has the ability to recognize and bind antigen, but generally with lower affinity than the entire binding site.

[0222] "Single-chain Fv" is also abbreviated as "sFv" or "scFv" and is a fragment comprising V sequences linked into a single polypeptide chain. H and V L In some embodiments, the scFv polypeptide comprises an antibody fragment comprising an antibody domain. H With V LThe polypeptide linker between the domains and connecting these domains enables scFv to retain or form the desired structure for antigen binding. Such peptide linkers can be incorporated into fusion polypeptides using standard techniques well known in the art. For a review of scFv, see Pluckthun, The Pharmacology of Monoclonal Antibodies, Vol. 113, Rosenburg and Moore, ed., Springer-Verlag, New York, pp. 269-315 (1994); Borrebaeck 1995, see below. In certain embodiments, an antibody or antigen-binding fragment includes an scFv comprising a VH domain, a VL domain, and a peptide linker connecting the VH domain to the VL domain. In a specific embodiment, an scFv comprises a VH domain connected to a VL domain via a peptide linker, which may be in a VH-linker-VL orientation or in a VL-linker-VH orientation. Any scFv disclosed herein can be engineered such that the C-terminus of the VL domain is linked to the N-terminus of the VH domain via a short peptide sequence, or vice versa (i.e., (N)VL(C)-linker-(N)VH(C) or (N)VH(C)-linker-(N)VL(C). Alternatively, in some embodiments, the linker can be attached to the N-terminal portion or N-terminus of the VH domain, the VL domain, or both.

[0223] The peptide linker sequence can be selected, for example, based on: (1) its ability to adopt a flexible, extended conformation; (2) its inability or inability to adopt a secondary structure that can interact with a functional epitope on the first and second polypeptides and / or on the target molecule; and / or (3) the lack or relative lack of hydrophobic residues or charged residues that may react with the polypeptides and / or target molecules. Other considerations for linker design (e.g., length) may include the conformation or range of conformations in which VH and VL can form a functional antigen binding site. In certain embodiments, the peptide linker sequence contains, for example, Gly, Asn, and Ser residues. Other nearly neutral amino acids (such as Thr and Ala) may also be included in the linker sequence. Other amino acid sequences that can be used effectively as linkers include those disclosed in Maratea et al., Gene 40:39-46 (1985); Murphy et al., Proc. Natl. Acad. Sci. USA 83:8258-8262 (1986); U.S. Pat. No. 4,935,233; and U.S. Pat. No. 4,751,180. Other illustrative and non-limiting examples of linkers, when present in a single iteration or repeated 1 to 5 times or more, can include, for example, Glu-Gly-Lys-Ser-Ser-Gly-Ser-Gly-Ser-Glu-Ser-Lys-Val-Asp (Chaudhary et al., Proc. Natl. Acad. Sci. USA 87: 1066-1070 (1990)) and Lys-Glu-Ser-Gly-Ser-Val-Ser-Ser-Glu-Gln-Leu-Ala-Gln-Phe-Arg-Ser-Leu-Asp (Bird et al., Science 242: 423-426 (1988)), as well as the pentamer Gly-Gly-Gly-Gly-Ser. Any suitable linker can be used, and generally, it can be about 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 15 23, 24, 25, 26, 27, 28, 29, 30, 40, 50, 60, 70, 80, 90, 100 amino acids in length, or less than about 200 amino acids in length, and will preferably have a flexible structure (which can provide flexibility and space for conformational movement between the two regions, domains, motifs, fragments or modules connected by the linker), and will preferably be biologically inert and / or have a low risk of immunogenicity in humans. scFvs can be constructed using any combination of VH and VL sequences disclosed herein, or any combination of CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 sequences.In some embodiments, a linker sequence is not required; for example, when the first and second polypeptides have non-essential N-terminal amino acid regions that can be used to separate the functional domains and prevent steric interference.

[0224] During antibody development, DNA in the germline variable region (V), joining region (J) and diversity region (D) loci may be rearranged and insertions and / or deletions of nucleotides in the coding sequence may occur. Somatic mutations may be encoded by the resulting sequence and may be identified by reference to the corresponding known germline sequence. In some contexts, somatic mutations that are unimportant to the desired properties of the antibody (e.g., binding to influenza NA antigens) or somatic mutations that confer undesirable properties to the antibody (e.g., increased risk of immunogenicity in subjects to whom the antibody is administered) or both may be replaced by corresponding germline-encoded amino acids or different amino acids, such that the desired properties of the antibody are improved or maintained and the undesirable properties of the antibody are reduced or eliminated. Therefore, in some embodiments, the antibodies or antigen-binding fragments of the present disclosure comprise at least one or more germline-encoded amino acids in the variable region compared to the parent antibody or antigen-binding fragment, provided that the parent antibody or antigen-binding fragment comprises one or more somatic mutations. Variable region and CDR amino acid sequences of exemplary anti-NA antibodies of the present disclosure are provided in Table 1 herein.

[0225] The polynucleotide sequences and other information for these and related human IG alleles are available, for example, at IMGT.org (see, for example).

[0226] In certain embodiments, the antibodies or antigen-binding fragments contain amino acid modifications (eg, substitution mutations) to remove the risk of undesirable oxidation, deamidation, and / or isomerization.

[0227] Also provided herein are variant antibodies comprising one or more amino acid changes in the variable region (e.g., VH, VL, framework, or CDR) compared to the presently disclosed ("parent") antibodies, wherein the variant antibodies are capable of binding to NA antigen.

[0228] In certain embodiments, the VH comprises, consists essentially of, or consists of any VH amino acid sequence listed in Table 1 and / or Table 2, and the VL comprises, consists essentially of, or consists of any VL amino acid sequence listed in Table 1 and / or Table 2.

[0229] refer to Figure 71 In certain embodiments, an antibody or antigen-binding fragment is provided, comprising Figure 71 The VH and VH of the FNI9 antibody shown Figure 71 The VL of the FNI9 antibody is shown, with the proviso that the antibody or antigen-binding fragment does not comprise the VH of FNI9-VH-WT and the VL of FNI9-VK-WT.

[0230] refer to Figure 71 In certain embodiments, an antibody or antigen-binding fragment is provided, which comprises: (i) a VH comprising the VH amino acid sequence of FNI9-VH-WT, FNI9-VH-FR124GL, FNI9-VH.4, FNI9-VH.5, FNI9-VH.6, FNI9-VH.7, FNI9-VH.8, FNI9-VH.9, FNI9-VH.10, FNI9-VH.11, FNI9-VH.12 or FNI9-VH.13; and (ii) a VL comprising the VL amino acid sequence of FNI9-VK.7.

[0231] refer to Figure 71 In certain embodiments, an antibody or antigen-binding fragment is provided, which comprises: (i) a VH comprising the VH amino acid sequence of FNI9-VH-WT, FNI9-VH-FR124GL, FNI9-VH.4, FNI9-VH.5, FNI9-VH.6, FNI9-VH.7, FNI9-VH.8, FNI9-VH.9, FNI9-VH.10, FNI9-VH.11, FNI9-VH.12 or FNI9-VH.13; and (ii) a VL comprising the VL amino acid sequence of FNI9-VK.8.

[0232] refer to Figure 71 In certain embodiments, an antibody or antigen-binding fragment is provided, which comprises: (i) a VH comprising the VH amino acid sequence of FNI9-VH-FR124GL, FNI9-VH.4, FNI9-VH.5, FNI9-VH.6, FNI9-VH.7, FNI9-VH.8, FNI9-VH.9, FNI9-VH.10, FNI9-VH.11, FNI9-VH.12 or FNI9-VH.13; and (ii) a VL comprising the VL amino acid sequence of FNI9-VK-WT.

[0233] refer to Figure 72 In certain embodiments, an antibody or antigen-binding fragment is provided, comprising Figure 72 VH and VL of the FNI9 variant antibodies are shown.

[0234] In certain embodiments, the antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3, and optionally the VH and VL, of the antibody "FNI9-v8.1," which differs from the antibody FNI9 by an S28T mutation in the VH. Compared to FNI9, FNI9-v8.1 has improved production titers when expressed as recombinant IgG1 by transiently transfected host cells. In the MUNANA assay, FNI9-v8.1 also has a lower IC50 for inhibiting the sialidase activity of certain N1 and N2 neuraminidase enzymes compared to FNI9. In the ELLA assay, FNI9-v8.1 also has a lower IC50 for inhibiting the sialidase activity of pseudovirus-derived neuraminidase compared to FNI9. FNI9-v8.1 also bound more strongly to N9_A_Anhui_2013 than FNI9, as assessed by flow cytometry. FNI9-v8.1 also had a higher affinity for certain IAV and IBV NA antigens (both those bearing glycans and those not bearing glycans) than FNI9, as assessed by surface plasmon resonance. FNI9-v8.1 also showed improved in vitro inhibition (reported as IC50 in ng / ml) of the sialidase activity of certain IAV and IBV NAs compared to FNI9.

[0235] FNI9-v8.1 comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 amino acid sequences of SEQ ID NOs.: 55 (GGTFNNQA), 4 (IFPISGTP), 5 (ARAGSDYFNRDLGWENYYFAS), 9 (RSVSSN), 10 (DAS), and 11 (QQYNNWPPWT), respectively, and the VH and VL amino acid sequences of SEQ ID NOs.: 54 and 8, respectively. It should be understood that "-v8.1" refers to an FNI9 variant comprising a "v8" VH (SEQ ID NO.: 54) and a "v1" VL (SEQ ID NO.: 8, the same VL as the parent FNI9).

[0236] In some embodiments, an antibody or antigen-binding fragment is provided, comprising: (i) a VH comprising or consisting of the amino acid sequence of any one of SEQ ID NO.: 2, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 and 65; and (ii) a VL comprising or consisting of the VL amino acid sequence of SEQ ID NO.: 8.

[0237] In certain embodiments, an antibody or antigen-binding fragment is provided, comprising: (i) a VH comprising the amino acid sequence QVHLVQSGAEVKEPGSSVTVSCKASGGTFNNQAISWVRQAPGQGLE WMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAV YYCARAGSDYFNRDLGWENYYFASWGQGTLVTVSS (SEQ ID NO.: 54); and (ii) a VL comprising the amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLI YDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPP WTFGQGTKVEIK (SEQ ID NO.: 8).

[0238] In certain embodiments, an antibody or antigen-binding fragment is provided comprising: (i) a VH consisting essentially of the amino acid sequence QVHLVQSGAEVKEPGSSVTVSCKASGGTFNNQAISWVRQAPGQGLE WMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAV YYCARAGSDYFNRDLGWENYYFAS WGQGTLVTVSS (SEQ ID NO.: 54); and (ii) a VL consisting essentially of the amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLI YDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPPWTFGQGTKVEIK (SEQ ID NO.: 8).

[0239] In certain embodiments, an antibody or antigen-binding fragment is provided, comprising: (i) a VH consisting of the amino acid sequence QVHLVQSGAEVKEPGSSVTVSCKASGGTFNNQAISWVRQAPGQGLE WMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAV YYCARAGSDYFNRDLGWENYYFASWGQGTLVTVSS (SEQ ID NO.: 54); and (ii) a VL consisting of the amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLI YDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPP WTFGQGTKVEIK (SEQ ID NO.: 8).

[0240] In certain embodiments, an antibody or antigen-binding fragment is provided, comprising: (i) a heavy chain comprising the VH amino acid sequence QVHLVQSGAEVKEμGSSVTVSCKASGGTFNNQAISWVRQAμGQGLE WMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAV YYCARAGSDYFNRDLGWENYYFASWGQGTLVTVSS (SEQ ID NO.: 54); and (ii) a light chain comprising the VL amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKμGQAPRLLI YDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPP WTFGQGTKVEIK (SEQ ID NO.: 8). In certain additional embodiments, the antibody or antigen-binding fragment is of (e.g., human) IgG1 isotype and optionally comprises M428L and N434S mutations. In some embodiments, the light chain is an IgG1 kappa light chain.

[0241] In certain embodiments, an antibody or antigen-binding fragment is provided that comprises: (i) two heavy chains, each comprising the VH amino acid sequence QVHLVQSGAEVKEμGSSVTVSCKASGGTFNNQAISWVRQAμGQGLE WMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAV YYCARAGSDYFNRDLGWENYYFASWGQGTLVTVSS (SEQ ID NO.: 54); and (ii) two light chains, each comprising the VL amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKμGQAPRLLI YDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPP WTFGQGTKVEIK (SEQ ID NO.: 8). In certain additional embodiments, the antibody or antigen-binding fragment is of the (e.g., human) IgG1 isotype and optionally comprises the M428L and N434S mutations. In some embodiments, each of the light chains is an IgG1 kappa light chain. In certain embodiments, an antibody or antigen-binding fragment is provided comprising: (i) a VH comprising CDRH1, CDRH2, and CDRH3 of the VH amino acid sequence QVHLVQSGAEVKEPGSSVTVSCKASGGTFNNQAISWVRQAPGQGLEWMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAVYYCARAGSDYFNRDLGWENYYFASWGQGTLVTVSS (SEQ ID NO.: 54), wherein optionally, the CDRs are defined according to IMGT; and (ii) a VL comprising the VL amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLI YDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPP WTFGQGTKVEIK (SEQ ID NO.: NO.:8), wherein optionally, the CDRs are defined according to IMGT.

[0242] In certain embodiments, an antibody or antigen-binding fragment is provided that comprises: (i) a heavy chain comprising, in VH, CDRH1, CDRH2, and CDRH3 of the VH amino acid sequence QVHLVQSGAEVKEμGSSVTVSCKASGGTFNNQAISWVRQAμGQGLE WMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAV YYCARAGSDYFNRDLGWENYYFASWGQGTLVTVSS (SEQ ID NO.: 54), wherein optionally, the CDRs are defined according to IMGT; and (ii) a light chain comprising in VL the VL amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKμGQAPRLLI YDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPP WTFGQGTKVEIK (SEQ ID NO.: 55). In some embodiments, the antibody or antigen-binding fragment is an IgG1 light chain (e.g., human) IgG1 isotype and optionally comprises M428L and N434S mutations. In some embodiments, the light chain is an IgG1 kappa light chain.

[0243] In certain embodiments, an antibody or antigen-binding fragment is provided that comprises: (i) two heavy chains, each comprising in VH a CDRH1, a CDRH2, and a CDRH3 of the VH amino acid sequence QVHLVQSGAEVKEPGSSVTVSCKASGGTFNNQAISWVRQAPGQGLE WMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAV YYCARAGSDYFNRDLGWENYYFASWGQGTLVTVSS (SEQ ID NO.: 54), wherein optionally, the CDRs are defined according to IMGT; and (ii) two light chains, each comprising in VL a VL amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLI YDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPPWTFGQGTKVEIK (SEQ ID NO.: NO.:8), wherein optionally, the CDRs are defined according to IMGT. In certain further embodiments, the antibody or antigen-binding fragment is of (e.g., human) IgG1 isotype and optionally comprises M428L and N434S mutations. In some embodiments, each of the light chains is an IgG1 kappa light chain.

[0244] In some embodiments, an antibody or antigen-binding fragment is provided, comprising: (i) a VH comprising or consisting of the amino acid sequence of any one of SEQ ID NO.: 2, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 and 65; and (ii) a VL comprising or consisting of the VL amino acid sequence of SEQ ID NO.: 37.

[0245] In some embodiments, an antibody or antigen-binding fragment is provided, comprising: (i) a VH comprising or consisting of the amino acid sequence of any one of SEQ ID NO.: 2, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 and 65; and (ii) a VL comprising or consisting of the VL amino acid sequence of SEQ ID NO.: 66.

[0246] In some embodiments, an antibody or antigen-binding fragment is provided, comprising: (i) a VH comprising or consisting of the amino acid sequence of any one of SEQ ID NO.: 2, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 and 65; and (ii) a VL comprising or consisting of the VL amino acid sequence of SEQ ID NO.: 68.

[0247] Table A provides the VH and VL amino acid SEQ ID NOs. of certain FNI9 variant antibodies of the present disclosure.

[0248]

[0249]

[0250] In some embodiments, the influenza comprises influenza A virus, influenza B virus, or both.

[0251] In certain embodiments, the antibodies or antigen-binding fragments of the present disclosure are monospecific (e.g., bind to a single epitope) or multispecific (e.g., bind to multiple epitopes and / or target molecules). Antibodies and antigen-binding fragments can be constructed in a variety of formats. Exemplary antibody formats are disclosed in Spiess et al., Mol. Immunol. 67(2):95 (2015) and in Brinkmann and Kontermann, mAbs 9(2):182-212 (2017), which formats and methods for their preparation are incorporated herein by reference and include, for example, bispecific T cell engagers (BiTEs), DARTs, Knobs-Into-Holes (KIH) assemblies, scFv-CH3-KIH assemblies, KIH common light chain antibodies, TandAbs, triabodies, TriBi minibodies, Fab-scFv, scFv-CH-CL-scFv, F(ab')2-scFv2, tetravalent HCabs, intrabodies, CrossMab, dual-acting Fab (DAF) (two-in-one or four-in-one), DutaMab, DT-IgG, charge pairs, Fab arm exchange (Fab-arm Exchange), SEEDbodies, Triomabs, LUZ-Y assemblies, Fcabs, kappa bodies, orthogonal Fabs, DVD-Igs (e.g., U.S. Pat. No. 8,258,268, the entirety of which is incorporated herein by reference), IgG(H)-scFv, scFv-(H)IgG, IgG(L)-scFv, scFv-(L)IgG, IgG(L,H)-Fv, IgG(H)-V, V(H)-IgG, IgG(L)-V, V(L)-IgG, KIH IgG-scFab, 2scFv-IgG, IgG-2scFv, scFv4-Ig, Zybodies, and DVI-IgG (four-in-one), as well as so-called FIT-Igs (e.g., PCT Publication No. WO 2015 / 103072, the entirety of which is incorporated herein by reference), the so-called WuxiBody format (e.g., PCT Publication No. WO 2015 / 103074, the entirety of which is incorporated herein by reference), 2019 / 057122, which formats are incorporated herein by reference in their entirety) and the so-called In-Elbow-Insert Ig format (IEI-Ig; for example, PCT Publication Nos. WO 2019 / 024979 and WO 2019 / 025391, which formats are incorporated herein by reference in their entirety).

[0252] In certain embodiments, the antibody or antigen-binding fragment comprises two or more VH domains, two or more VL domains, or both (i.e., two or more VH domains and two or more VL domains). In a specific embodiment, the antigen-binding fragment has the format (N-terminal to C-terminal direction) VH-linker-VL-linker-VH-linker-VL, wherein the two VH sequences may be the same or different and the two VL sequences may be the same or different. Such linked scFvs may comprise any combination of VH and VL domains arranged to bind to a given target, and in a format comprising two or more VH and / or two or more VL, may bind to one, two or more different epitopes or antigens. It should be understood that formats incorporating multiple antigen-binding domains may comprise VH and / or VL sequences in any combination or orientation. For example, the antigen-binding fragment can have the format VL-linker-VH-linker-VL-linker-VH, VH-linker-VL-linker-VL-linker-VH, or VL-linker-VH-linker-VH-linker-VL.

[0253] The monospecific or multispecific antibodies or antigen-binding fragments of the present disclosure are constructed to comprise any combination of VH and VL sequences and / or any combination of CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 sequences disclosed herein. In some embodiments, bispecific or multispecific antibodies or antigen-binding fragments may comprise one, two, or more antigen-binding domains (e.g., VH and VL) disclosed herein. There may be two or more binding domains that bind to the same or different NA epitopes, and in some embodiments, bispecific or multispecific antibodies or antigen-binding fragments as provided herein comprise additional NA-specific binding domains and / or may comprise binding domains that bind to completely different antigens or pathogens.

[0254] In any of the presently disclosed embodiments, the antibody or antigen-binding fragment can be multispecific; eg, bispecific, trispecific, etc.

[0255] In certain embodiments, an antibody or antigen-binding fragment comprises an Fc polypeptide or fragment thereof. An "Fc" fragment or Fc polypeptide comprises the carboxyl-terminal portions of two antibody H chains (i.e., the CH2 and CH3 domains of an IgG) held together by disulfide bonds. An Fc polypeptide may comprise a dimer composed of two Fc polypeptides (i.e., two CH2-CH3 polypeptides). Antibody "effector functions" refer to biological activities attributable to the Fc region (a native sequence Fc region or an amino acid sequence variant Fc region) of an antibody and vary with the antibody isotype. Examples of antibody effector functions include: C1q binding and complement-dependent cytotoxicity; Fc receptor binding; antibody-dependent cellular cytotoxicity (ADCC); phagocytosis; downregulation of cell surface receptors (e.g., B cell receptors); and B cell activation. As discussed herein, the Fc domain may be modified (e.g., by amino acid substitution) to modify (e.g., improve, reduce, or eliminate) one or more functions of an Fc-containing polypeptide (e.g., an antibody of the present disclosure). Such functions include, for example, Fc receptor (FcR) binding, antibody half-life modulation (e.g., by binding to FcRn), ADCC function, protein A binding, protein G binding, and complement binding. Amino acid modifications that modify (e.g., improve, reduce, or eliminate) Fc function include, for example, T250Q / M428L, M252Y / S254T / T256E, H433K / N434F, M428L / N434S, M428L / 434A, E233P / L234V / L235A / G236+A327G / A330S / P331S, E333A, S239D / A330L / I332E, P257VQ311, K326W / E333S, S239D / I332E / G236A, N297Q, K322A, S228P, L235E+E318A / K320A / K322A, L234A / L235A (also referred to herein as "LALA"), and L234A / L235A / P329G mutations, some of which were published at InvivoGen (2011) and available at invivogen.com / PDF / review / review-Engineered-Fc-Regions-invivogen.pdf?utm_source=review&utm_medium=pdf&utm_

[0256] campaign=review&utm_content=Engineered-Fc-Regions is summarized and annotated in “Engineered Fc Regions,” available online and incorporated herein by reference.

[0257] For example, to activate the complement cascade, when an immunoglobulin molecule is attached to an antigenic target, the C1q protein complex can bind to at least two IgG1 molecules or one IgM molecule (Ward, ES and Ghetie, V., Ther. Immunol. 2 (1995) 77-94). Burton, DR (Mol. Immunol. 22 (1985) 161-206) described the involvement of the heavy chain region comprising amino acid residues 318 to 337 in complement fixation. Duncan, AR and Winter, G. (Nature 332 (1988) 738-740) used site-directed mutagenesis to report that Glu318, Lys320, and Lys322 form a binding site for C1q. The role of Glu318, Lys320, and Lys322 residues in C1q binding was confirmed by the ability of short synthetic peptides containing these residues to inhibit complement-mediated lysis.

[0258] For example, FcR binding can be mediated by the interaction of the Fc portion (of an antibody) with an Fc receptor (FcR), which is a specialized cell surface receptor on cells including hematopoietic cells. Fc receptors belong to the immunoglobulin superfamily and have been shown to mediate both the clearance of antibody-coated pathogens by phagocytosis of immune complexes and the lysis of erythrocytes and various other cellular targets (e.g., tumor cells) coated with the corresponding antibody by antibody-dependent cellular cytotoxicity (ADCC; Van de Winkel, JG and Anderson, CL, J. Leukoc. Biol. 49 (1991) 511-524). FcRs are defined by their specificity for immunoglobulin classes; the Fc receptors for IgG antibodies are referred to as FcγRs, the Fc receptors for IgE antibodies are referred to as FcεRs, the Fc receptors for IgA antibodies are referred to as FcαRs, etc., and the neonatal Fc receptor is referred to as FcRn. Fc receptor binding is described, for example, in Ravetch, JV and Kinet, JP, Annu. Rev. Immunol. 9 (1991) 457-492; Capel, PJ et al., Immunomethods 4 (1994) 25-34; de Haas, M. et al., J Lab. Clin. Med. 126 (1995) 330-341; and Gessner, JE et al., Ann. Hematol. 76 (1998) 231-248.

[0259] Cross-linking of the Fc domain of native IgG antibodies to receptors (FcγRs) triggers a variety of effector functions, including phagocytosis, antibody-dependent cellular cytotoxicity, and release of inflammatory mediators, as well as immune complex clearance and regulation of antibody production. This article considers the Fc portion that provides cross-linking of receptors (e.g., FcγRs). In humans, the following three classes of FcγRs have been characterized to date: (i) FcγRI (CD64), which binds monomeric IgG with high affinity and is expressed on macrophages, monocytes, neutrophils, and eosinophils; and (ii) FcγRII (CD32), which binds complexed IgG with moderate to low affinity, is widely expressed (particularly on leukocytes), is considered a core player in antibody-mediated immunity, and can be divided into FcγRIIA, FcγRIIB, and FcγRIIC, which play a key role in the immune system. (iii) FcγRIII (CD16), which binds IgG with intermediate to low affinity and is found in two forms: FcγRIIIA, which is found on NK cells, macrophages, eosinophils, and some monocytes and T cells and is thought to mediate ADCC; and FcγRIIIB, which is highly expressed on neutrophils.

[0260] FcγRIIA is found on many cells (e.g., macrophages, monocytes, neutrophils) involved in killing and seems to be able to activate the killing process. FcγRIIB seems to play a role in the suppression process and is found on B cells, macrophages, mast cells and eosinophils. Importantly, it has been shown that 75% of all FcγRIIB are found in the liver (Ganesan, LP et al., 2012: "FcγRIIb on liver sinusoidal endothelium clearssmall immune complexes," Journal of Immunology 189: 4981-4988). FcγRIIB is expressed in large quantities in Kupffer cells on the liver sinusoidal endothelium (referred to as LSEC) and in the liver, and LSEC is the main site of clearing small immune complexes (Ganesan, LP et al., 2012: FcγRIIb on liver sinusoidal endothelium clearssmall immune complexes. Journal of Immunology 189: 4981-4988).

[0261] In some embodiments, the antibodies and antigen-binding fragments thereof disclosed herein comprise an Fc polypeptide or fragment thereof for binding to FcγRIIb, particularly an Fc region, such as, for example, an IgG-type antibody. In addition, the Fc portion can be engineered to enhance FcγRIIB binding by introducing mutations S267E and L328F, as described in Chu, SY et al., 2008: Inhibition of Bcell receptor-mediated activation of primary human B cells by coengagement of CD19 and FcγRIIb with Fc-engineered antibodies. Molecular Immunology 45, 3926-3933. Thus, the clearance of immune complexes can be enhanced (Chu, S. et al., 2014: Accelerated Clearance of IgE In Chimpanzees Is Mediated By Xmab7195, An Fc-Engineered Antibody With Enhanced Affinity For Inhibitory Receptor FcγRIIb. Am J Respir Crit, American Thoracic Society International Conference Abstracts). In some embodiments, the antibodies or antigen-binding fragments thereof of the present disclosure comprise an engineered Fc portion having mutations S267E and L328F, specifically as described in Chu, SY et al., 2008: Inhibition of b cell receptor-mediated activation of primary human B cells by coengagement of CD19 and FcγRIIb with Fc-engineered antibodies. Molecular Immunology 45, 3926-3933.

[0262] On B cells, FcγRIIB may function to inhibit further immunoglobulin production and isotype switching to, for example, the IgE class. On macrophages, FcγRIIB is thought to inhibit phagocytosis mediated by FcγRIIA. On eosinophils and mast cells, the B form may help inhibit activation of these cells by binding of IgE to its individual receptors.

[0263] Regarding FcγRI binding, modification of at least one of E233-G236, P238, D265, N297, A327, and P329 in native IgG reduced binding to FcγRI. IgG2 residues substituted to the corresponding positions at positions 233-236 in IgG1 and IgG4 reduced binding of IgG1 and IgG4 to FcγRI by 10 3 fold, and eliminated the response of human monocytes to antibody-sensitized erythrocytes (Armour, KL et al., Eur. J. Immunol. 29 (1999) 2613-2624).

[0264] With respect to FcyRII binding, reduced binding to FcyRIIA was found, for example, for IgG mutations of at least one of E233-G236, P238, D265, N297, A327, P329, D270, Q295, A327, R292, and K414.

[0265] The two allelic forms of human FcγRIIA are the "H131" variant, which binds to IgG1 Fc with higher affinity, and the "R131" variant, which binds to IgG1 Fc with lower affinity. See, eg, Bruhns et al., Blood 113:3716-3725 (2009).

[0266] Regarding FcγRIII binding, reduced binding to FcγRIIIA was found, for example, for mutations in at least one of E233-G236, P238, D265, N297, A327, P329, D270, Q295, A327, S239, E269, E293, Y296, V303, A327, K338, and D376. Mapping of the binding site for the Fc receptor on human IgG1, the aforementioned mutation sites, and methods for measuring binding to FcγRI and FcγRIIA are described in Shields, RL et al., J. Biol. Chem. 276 (2001) 6591-6604.

[0267] The two allelic forms of human FcγRIIIA are the "F158" variant, which binds to IgG1 Fc with lower affinity, and the "V158" variant, which binds to IgG1 Fc with higher affinity. See, eg, Bruhns et al., Blood 113:3716-3125 (2009).

[0268] Regarding binding to FcγRII, two regions of native IgG Fc appear to be involved in the interaction between FcγRII and IgG, namely (i) the lower hinge site of IgG Fc, specifically amino acid residues L, L, G, G (234–237, EU numbering); and (ii) adjacent regions of the CH2 domain of IgG Fc, specifically loops and chains in the upper CH2 domain adjacent to the lower hinge region, such as in the region of P331 (Wines, BD et al., J. Immunol. 2000; 164: 5313–5318). Furthermore, FcγRI appears to bind to the same site on IgG Fc, whereas FcRn and protein A bind to different sites on IgG Fc, which appear to be located at the CH2-CH3 interface (Wines, BD et al., J. Immunol. 2000; 164: 5313–5318).

[0269] Mutations that increase the binding affinity of the Fc polypeptides or fragments thereof of the present disclosure to (i.e., one or more) Fcγ receptors (e.g., compared to a reference Fc polypeptide or fragment thereof or a reference Fc polypeptide or fragment thereof that does not contain the mutation) are also contemplated. See, e.g., Delillo and Ravetch, Cell 161(5):1035-1045 (2015) and Ahmed et al., J. Struc. Biol. 194(1):78 (2016), which Fc mutations and techniques are incorporated herein by reference.

[0270] In any of the embodiments disclosed herein, the antibody or antigen-binding fragment may include an Fc polypeptide or fragment thereof comprising a mutation selected from the group consisting of G236A, S239D, A330L, and I332E, or a combination of any two or more thereof; for example, S239D / I332E, S239D / A330L / I332E, G236A / S239D / I332E, G236A / A330L / I332E (also referred to herein as "GAALIE"), or G236A / S239D / A330L / I332E. In some embodiments, the Fc polypeptide or fragment thereof does not comprise S239D. In some embodiments, the Fc polypeptide or fragment thereof comprises an S at position 239 (EU numbering).

[0271] In certain embodiments, the Fc polypeptide or fragment thereof may comprise or consist of at least a portion of an Fc polypeptide or fragment thereof that participates in FcRn binding. In certain embodiments, the Fc polypeptide or fragment thereof comprises one or more amino acid modifications that increase binding affinity to FcRn (e.g., enhance binding to FcRn) (e.g., at a pH of about 6.0), and in some embodiments, thereby extending the in vivo half-life of the molecule comprising the Fc polypeptide or fragment thereof (e.g., compared to a reference Fc polypeptide or fragment thereof or antibody that is otherwise identical but does not comprise the modification). In certain embodiments, the Fc polypeptide or fragment thereof comprises or is derived from IgG Fc and the half-life extending mutations comprise any one or more of the following: M428L; N434S; N434H; N434A; N434S; M252Y; S254T; T256E; T250Q; P257I; Q311I; D376V; T307A; E380A (EU numbering). In certain embodiments, the half-life extension mutation includes M428L / N434S (also referred to herein as "MLNS", "LS", "-LS" and "-LS"). In certain embodiments, the half-life extension mutation includes M252Y / S254T / T256E. In certain embodiments, the half-life extension mutation includes T250Q / M428L. In certain embodiments, the half-life extension mutation includes P257I / Q311I. In certain embodiments, the half-life extension mutation includes P257I / N434H. In certain embodiments, the half-life extension mutation includes D376V / N434H. In certain embodiments, the half-life extension mutation includes T307A / E380A / N434A. In certain embodiments, the half-life extension mutation includes M428L / N434A.

[0272] In some embodiments, the antibody or antigen-binding fragment includes an Fc portion comprising a substitution mutation M428L / N434S. In some embodiments, the antibody or antigen-binding fragment includes an Fc portion comprising a substitution mutation M428L / N434A. In some embodiments, the antibody or antigen-binding fragment includes an Fc polypeptide or fragment thereof comprising a substitution mutation G236A / A330L / I332E. In certain embodiments, the antibody or antigen-binding fragment includes an (e.g., IgG) Fc portion comprising a G236A mutation, an A330L mutation, and an I332E mutation (GAALIE), and does not include an S239D mutation (e.g., comprising a native S at position 239). In certain embodiments, the antibody or antigen-binding fragment comprises an Fc polypeptide or fragment thereof comprising the substitution mutations: M428L / N434S and G236A / A330L / I332E, and optionally does not comprise S239D (e.g., comprises S at 239). In certain embodiments, the antibody or antigen-binding fragment comprises an Fc polypeptide or fragment thereof comprising the substitution mutations: M428L / N434S and G236A / S239D / A330L / I332E.

[0273] In certain embodiments, the antibody or antigen-binding fragment comprises a mutation that alters glycosylation, wherein the mutation that alters glycosylation comprises N297A, N297Q, or N297G, and / or the antibody or antigen-binding fragment is partially or completely deglycosylated and / or partially or completely defucosylated. Host cell lines and methods for preparing partially or completely deglycosylated or partially or completely defucosylated antibodies and antigen-binding fragments are known (see, e.g., PCT Publication No. WO2016 / 181357; Suzuki et al., Clin. Cancer Res. 13(6): 1875-82 (2007); Huang et al., mAbs 6: 1-12 (2018)).

[0274] In certain embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising one or more mutations in the hinge, CH2 and / or CH3 (or in the Fc), wherein the antibody or antigen-binding fragment has one or more improved properties relative to, e.g., an antibody or antigen-binding fragment comprising a reference wild-type Fc polypeptide and / or comprising a known variant Fc polypeptide. The presently disclosed Fc variants have, for example: increased binding to one or more human FcγRAs (e.g., FcγRIIA and / or FcγRIIIA); reduced / attenuated binding to human FcγRIIB; increased binding to one or more human FcγRAs compared to binding to human FcγRIIB; increased thermal stability compared to known Fc polypeptides; increased binding to human C1q; increased human FcγRIIIA signaling in host cells expressing FcγRIIIA; increased human FcγRIIIA signaling in host cells expressing FcγRIIA; reduced human FcγRIIB signaling in host cells expressing FcγRIIB; a relative increase in binding to FcγRAs compared to FcγRIIB; improved manufacturing quality compared to known Fc polypeptides; and combinations of such features.

[0275] In certain embodiments, antibodies comprising the variant Fc polypeptides of the present disclosure provide surprising advantages, such as any one or more of the following: increased binding affinity for one or more human FcγRAs (e.g., as determined by surface plasmon resonance using a Biacore instrument, and / or as determined by electrochemiluminescence assays such as meso- based assays) compared to antibodies comprising a reference Fc polypeptide without the mutation and / or fucosylation state;

[0015] The present invention provides a method for detecting the expression of an Fc variant antibody comprising an antibody that binds to a human FcγRIIB and / or induces increased signaling of one or more human FcγRAs (e.g., as determined using (1) an Fc variant antibody, (2) an antigen-expressing target cell, and (3) a reporter cell expressing one or more human FcγRAs, optionally driving expression of a reporter gene such as, for example, GFP or luciferase); reduced binding affinity for human FcγRIIB and / or induces reduced signaling of human FcγRIIB compared to an antibody comprising a reference Fc polypeptide that does not contain the mutation and / or fucosylation state; a method for detecting the expression of an Fc variant antibody comprising an antibody that binds to a human FcγRIIB and / or induces decreased signaling of human FcγRIIB across human FcγRIIA-H, human FcγRIIA-R, human FcγRIIB, human FcγRIIIA-F, and human FcγRIIB ... increased signaling of human FcγRIIB across human FcγRIIA-H, human FcγRIIA-R, human FcγRIIB, human FcγRIIIA-F, and human FcγRIIB; a method for detecting the expression of an Fc variant antibody comprising an antibody that binds to a human FcγRIIB and / or induces decreased signaling of human FcγRIIB; a method for detecting the expression of an Fc variant antibody comprising an antibody that binds to a human FcγRIIB and / or induces increased signaling of human FcγRIIB The invention also provides a method for preparing a γRIIIA-V antibody comprising a variant Fc polypeptide or fragment thereof comprising a γRIIIA-V antibody, wherein the improved binding comprises an overall increase in binding and / or activation of FcγRA signaling relative to binding and / or activation of inhibitory FcγR signaling compared to an antibody comprising a reference Fc polypeptide without the mutations and / or fucosylation state; an increased binding affinity for human C1q compared to an antibody comprising a reference Fc polypeptide without the mutations and / or fucosylation state; no adverse effect or substantially no adverse effect on thermal stability compared to a variant Fc polypeptide or fragment thereof without the mutations and / or fucosylation state, a negative effect of decreased thermal stability (e.g., a human IgG1 comprising the mutations G236A, A330L, and I332E) Fc (e.g., less or no lowering of the melting temperature compared to an antibody comprising a human IgG1 Fc with the mutations G236A, A330L, and I332E, or a higher melting temperature than an antibody comprising a human IgG1 Fc with the mutations G236A, A330L, and I332E); increasing specific lysis of antigen-expressing target cells (e.g., via ADCC) by natural killer cells and / or PBMCs (e.g., expressing F158 / V158 or V158 / V158 FcγRIIIA) compared to an antibody comprising a reference Fc polypeptide without the mutations and / or fucosylation state (e.g., an antibody comprising a human IgG1 Fc with the mutations G236A, A330L, and I332E);increasing ADCP of monocytes (e.g., CD14+ monocytes, optionally expressing F158 / V158 FcγRIIA and R131 / H131 FcγRIIA or F158 / F158 FcγRIIA and R131 / H131 FcγRIIA) against antigen-expressing target cells compared to an antibody comprising a reference Fc polypeptide without mutations and / or fucosylation state; increasing the percentage of CD83+ cells (e.g., moDCs) in a sample and / or increasing expression of CD83 by moDCs when provided in combination with the antigen compared to an antibody comprising a reference Fc polypeptide without mutations and / or fucosylation state when provided in combination with the antigen; increasing production of one or more cytokines (optionally selected from the group consisting of IL-1β, IFN-γ, IL-6, and TNF-α) by moDCs in a sample when provided in combination with the antigen compared to an antibody comprising a reference Fc polypeptide without mutations and / or fucosylation state when provided in combination with the antigen and / or increases the ability of moDC to stimulate antigen-specific CD4+ T cells when presented to moDC in combination with the antigen compared to an antibody comprising a reference Fc polypeptide without mutation and / or fucosylation state when presented to moDC in combination with the antigen, wherein optionally (1) the moDC and CD4+ T cells are from the same (optionally antigen-vaccinated) subject, and / or (2) stimulation of antigen-specific CD4+ T cells is determined by increased expression of CD25 and / or increased proliferation (e.g., as determined by a decrease in CFSE staining over time) and / or increased expression of CD69 and / or increased expression of NF AT and / or increased expression of CD44 by antigen-specific CD4+ T cells.

[0276] In some embodiments, the engineered Fc or Fc fragment of the present disclosure (or polypeptides comprising the same) comprises two or more substitution mutations compared to a reference wild-type Fc or Fc fragment, and the combined effect of the two or more substitutions is different from and optionally greater than that expected based on the effect of the individual component substitution mutations and / or based on the effect of a subset of the two or more substitution mutations. In other words, in some embodiments, the combined mutations have a non-additive or synergistic effect with reference to the individual component mutations and / or a subset thereof.

[0277] In some embodiments, the presently disclosed antibodies or antigen-binding fragments comprising Fc variants have properties such as effector function, ability to bind to human C1q, ability to induce FcγRA-mediated cell signaling, ability to bind to human FcRn, ability to promote ADCP, ability to promote ADCC, ability to promote CD4+ T cell activation, etc.

[0278] The presently disclosed polypeptides include those comprising variants of an IgG Fc polypeptide or fragment thereof, wherein the variant comprises one or more modifications compared to an IgG Fc polypeptide or fragment thereof. It is understood that, unless otherwise indicated, a "reference" polypeptide or antibody (e.g., a reference IgG Fc polypeptide or fragment thereof, a reference antibody, a reference CH2 polypeptide, a reference IgG hinge-CH2, a reference IgG hinge-Fc polypeptide, a reference CH3 polypeptide) is preferably identical to the recited molecule (e.g., a variant of an Fc polypeptide or fragment thereof; a polypeptide comprising such a variant; an antibody comprising an Fc polypeptide variant) except for the recited difference or differences.

[0279] For example, it will be understood that for a variant IgG1 Fc polypeptide comprising an alanine (A) amino acid at EU position 236, the reference Fc polypeptide comprises an IgG1 Fc polypeptide that is otherwise identical to the variant except that the native glycine (G) amino acid is found at EU position 236. As another example, for a variant of an Fc polypeptide fragment (e.g., containing a portion of CH2 and CH3), the reference Fc polypeptide fragment preferably has the same length as the variant and preferably differs from the variant only in the stated characteristics (e.g., one or more amino acid mutations present in the variant). In some embodiments, the reference Fc polypeptide, Fc polypeptide fragment, or antibody comprises a wild-type amino acid sequence (e.g., wild-type human IgG1). Except for the stated differences present in the variant, the reference Fc polypeptide, Fc polypeptide fragment, or antibody will have the same isotype as the variant, and preferably the same allotype. In the case of a reference antibody, the Fab or other antigen binding domains will preferably be the same as those present in the specified antibody comprising the variant Fc polypeptide or fragment thereof.

[0280] In some embodiments, the variant of IgG Fc polypeptide or its fragment comprises one or more amino acid substitutions compared to a reference (e.g., wild-type) IgG Fc polypeptide or its fragment. In this article, the position of amino acids in variant IgG Fc polypeptide or fragment can be described by reference to "EU position". It should be understood that "EU position" follows the EU numbering system as listed in Kabat. As an illustration, it should be understood that in the example of the human IgG1 CH1-CH3 amino acid sequence provided below, the first amino acid (A) corresponds to EU position 118, and the last amino acid (K) corresponds to EU position 447:

[0281] ASTKGPSVFP LAPSSKSTSG GTAALGCLVK DYFPEPVTVS

[0282] WNSGALTSGV HTFPAVLQSS GLYSLSSVVT VPSSSLGTQT

[0283] YICNVNHKPS NTKVDKKVEP KSCDKTHTCP PCPAPELLGG

[0284] PSVFLFPPKP KDTLMISRTP EVTCVVVDVS HEDPEVKFNW

[0285] YVDGVEVHNA KTKPREEQYN STYRVVS VLT VLHQDWLNGK

[0286] EYKCKVSNKA LPAPIEKTIS KAKGQPREPQ VYTLPPSRDE

[0287] LTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPV

[0288] LDSDGSFFLY SKLTVDKSRW QQGNVFSCSV MHEALHNHYT

[0289] QKSLSLSPGK

[0290] Thus, it should be understood that, unless otherwise indicated, the positions of the amino acids recited follow the EU numbering of human IgG1, even if a complete antibody heavy chain, complete CH1-CH3, complete CH2-CH3, etc., is not present or is not explicitly stated. In other words, for example, if only the hinge-CH2 is described and CH3 and / or CH1 may not be present, the positions of the amino acids in the hinge-CH2 are described with reference to the EU numbering, unless otherwise indicated. The correspondence between the EU numbering, Kabat numbering, IMGT exon numbering, and IMGT unique numbering of immunoglobulin G heavy chain constant domains is known in the art and is shown, for example, in the IMGT Scientific Chart (www.imgt.org / IMGTScientificChart / Numbering / Hu_IGHGnber.html; created May 17, 2001, accessed May 23, 2021, and last updated January 20, 2020).

[0291] Certain embodiments of the Fc variants of the present disclosure (fucosylated unless otherwise indicated) and their non-limiting properties are summarized in Table B.

[0292] Table B. Certain Fc variants and their properties

[0293]

[0294]

[0295]

[0296]

[0297] Additional features of the disclosed Fc variant-containing antibodies are shown in the present Examples and Figures, and described herein.

[0298] It should be understood that two or more amino acid substitutions present in a variant can be expressed in a variety of ways, for example, as G236A_Y300L or as G236A / Y300L. In addition, abbreviated forms including the original amino acid and the amino acid resulting from the substitution can be used to refer to a mutation or combination of mutations. For example, G236A can be described as "GA" or "236A"; G236A_Y300L can be described as "GAYL"; G236A_L328V_Q295E can be described as "GALVQE"; G236A_R292P_Y300L can be described as "GARPYL", G236A_R292P_I377N can be described as "GARPIN", etc.

[0299] In any of the embodiments disclosed herein, the variant of the Fc polypeptide or fragment thereof may be derived from or comprise a human Fc polypeptide or fragment thereof, and / or may be derived from or comprise a human IgG1, human IgG2, human IgG3 or human IgG4 isotype. In this context, the expression "derived from" means that the variant is identical to the polypeptide or isotype mentioned except for the specified modification (e.g., amino acid substitution). For example, a variant Fc polypeptide comprising a wild-type human IgG1 Fc amino acid sequence but excluding the amino acid substitution mutation G236A_L328V_Q295E (and optionally, other amino acid substitutions) may be referred to as "derived from" wild-type human IgG1 Fc. In any of the embodiments disclosed herein, the polypeptide, CH2, Fc, Fc fragment or antibody may comprise a human Ig sequence, such as a human IgG1 sequence. In some embodiments, the polypeptide, CH2, Fc, Fc fragment or antibody may comprise a natural or wild-type human Ig sequence except for the mutation, or may comprise a human Ig (e.g., IgG) sequence containing one or more additional mutations.

[0300] The antibody or antigen-binding fragment can be any allotype or combination of allotypes. "Allotype" refers to the allelic variation found in the IgG subclass. For example, allotypes can include G1m1 (or G1m(a)), G1m2 (or G1m(x)), G1m3 (or G1m(f)), G1m17 (or Gm(z))m), G1m27 and / or G1m28 (G1m27 and G1m28 have been described as "alloallotypes").

[0301] The G1m3 and G1m17 allotypes are located at the same position in the CH1 domain (position 214 according to EU numbering). G1m3 contains R214 (EU), while G1m17 contains K214 (EU). The G1m1 allotype is located in the CH3 domain (at positions 356 and 358 (EU)) and refers to the substitutions E356D and M358L. The G1m2 allotype refers to the substitution of alanine at position 431 (EU) with glycine. Glm allotypes, heteromorphic allotypes, and their characteristics are known in the art and described, for example, at www.imgt.org / IMGTrepertoire / Proteins / allotypes / human / IGH / IGHC / Glm_allotypes.html and in Lefranc, M.-P. and Lefranc, G. Human Gm, Km and Am allotypes and their molecular characterization: a remarkable demonstration of polymorphism, In: B. Tait, F. Christiansen (eds.), Immunogenetics, Chapter 34, Humana Press, Springer, New York, USA. Methods Mol. Biol. 2012; 882, 635-680. PMID: 22665258, LIGM: 406, the contents of which and allotype and heteromorphic information are incorporated herein by reference.

[0302] The G1m1 allotype can be combined, for example, with the G1m3, G1m 17, G1m27, G1m2, and / or G1m28 allotypes. In some embodiments, the allotype is G1m3 without G1m1 (G1m3,-1). In some embodiments, the allotype is the G1m17,1 allotype. In some embodiments, the allotype is G1m3,1. In some embodiments, the allotype is G1m17 without G1m1 (G1m17,-1). Optionally, these allotypes can be combined (or not combined) with the G1m2, G1m27, or G1m28 allotypes. For example, the allotype can be G1m17,1,2.

[0303] In some embodiments, the antibodies or antigen-binding fragments of the present disclosure comprise a G1m3 allotype or a G1m3,1 allotype. In some embodiments, the antibodies or antigen-binding fragments of the present disclosure comprise a G1m3 allotype and comprise M428L and N434S or M428L and N434A mutations or any other mutations that enhance binding to human FcRn, such as those described herein. In some embodiments, the antibodies or antigen-binding fragments of the present disclosure comprise a G1m3,1 allotype and comprise M428L and N434S or M428L and N434A mutations or any other mutations that enhance binding to human FcRn, such as those described herein. In some embodiments, the antibodies or antigen-binding fragments of the present disclosure comprise a G1m17,1 allotype. In some embodiments, the antibodies or antigen-binding fragments of the present disclosure comprise the G1m17,1 allotype and comprise M428L and N434S or M428L and N434A mutations, or any other mutations that enhance binding to human FcRn, as further described herein.

[0304] In certain embodiments, a variant of an Fc polypeptide comprises only the specified or stated amino acid mutations (e.g., substitutions) and does not comprise any further amino acid substitutions or mutations; e.g., relative to a reference polypeptide (e.g., a wild-type Fc polypeptide or fragment thereof). For example, in some embodiments, a variant Fc polypeptide comprising the amino acid substitutions G236A_Y300L does not comprise any other amino acid substitutions; i.e., comprises an amino acid sequence that is wild-type except for G236A and Y300L.

[0305] In some embodiments, variants of Fc polypeptides may comprise one or more additional amino acid mutations (e.g., substitutions), which may be designated (e.g., M428L_N434S; M428L_N434A). In some embodiments, one or more additional amino acid mutations are physically distant from the stated amino acid position in the tertiary structure and / or are of such a nature (e.g., conservative substitutions) that one or more functions of the stated Fc variant or fragment thereof are not reduced or reduced by no more than 50%, no more than 40%, no more than 30%, no more than 25%, no more than 20%, no more than 15%, no more than 10% or no more than 5%, or reduced by no more than 10-fold, no more than 9-fold, no more than 8-fold, no more than 7-fold, no more than 6-fold, no more than 5-fold, no more than 4-fold, no more than 3-fold, no more than 2-fold or no more than 1.5-fold. In some embodiments, variants of Fc polypeptides comprise mutations M428L and N434S or mutations M428L and N434A or any other mutation that enhances binding to human FcRn, including those described herein.

[0306] In some embodiments, an antibody or antigen-binding fragment (further described herein) is provided, which comprises in a (e.g., human) IgG1 heavy chain the amino acid mutations listed in any one of (i) to (xviii): (i) G236A, L328V and Q295E; (ii) G236A, P230A and Q295E; (iii) G236A, R292P and I377N; (iv) G236A, K334A and Q295E; (v) G236S, R292P and Y300L; (vi) G236A and Y300L; (vii) G236A, R292P and Y300L; (viii) G236S, (xvi) G236W; (xvii) F243L, G446E, P396L and S267E; (xviii) G236A, S239D and H268E, wherein the numbering of amino acid residues is according to the EU index as set forth in Kabat. In certain embodiments, the antibody or antigen-binding fragment is afucosylated. In some embodiments, the antibody or antigen-binding fragment further comprises one or more mutations that enhance binding to human FcRn, such as M428L and N434S mutations or M428L and N434A mutations (EU numbering) or any other mutation that enhances binding to human FcRn, such as those described herein. In certain embodiments, the antibody or antigen-binding fragment is afucosylated. In some embodiments, the IgG1 heavy chain comprises CH1-CH3 or CH2-CH3 or hinge-CH2-CH3, wherein the CH1-CH3 or CH2-CH3 or hinge-CH2-CH3 are at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical (or similar) to wild-type human IgG1 CH1-CH3 or CH2-CH3 or hinge-CH2-CH3, respectively.In certain embodiments, the antibodies or antigen-binding fragments of the present disclosure comprise an Fc variant comprising an amino acid sequence that is at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical (or similar) to the amino acid sequence set forth in any one of SEQ ID NOs.: 69-95.

[0307] In some embodiments, the antibody or antigen-binding fragment comprises an amino acid sequence as set forth in any one of SEQ ID NOs.: 69-95, or a variant thereof, for example, the variant further comprises one or more mutations that enhance binding to human FcRn, such as M428L and N434S mutations or M428L and N434A mutations (EU numbering), or any other mutation that enhances binding to human FcRn, including those described herein. In some embodiments, the antibody or antigen-binding fragment comprises an amino acid sequence that differs from the amino acid sequence as set forth in any one of SEQ ID NOs.: 69-95 only in one or more IgG1 allotype-specific mutations and / or the presence of M428L and N434S mutations or M428L and N434A mutations or other mutations that enhance binding to human FcRn.

[0308] The antibodies or antigen-binding fragments of the present disclosure can be fucosylated (e.g., comprising one or more fucosyl moieties, and typically comprising a native (wild-type) fucosylation pattern or a fucosylation pattern having one or more additional or fewer fucosyl moieties compared to native), or can be defucosylated. Specifically, native IgG1 antibodies carry a glycan site at N297, and this is typically the only site where a core fucosyl moiety can be found in an antibody, but some glycan sites can be generated by mutation (e.g., in the variable domain) during antibody development. Fucosylation of the antibody or antigen-binding fragment can be affected by introducing amino acid mutations to introduce or disrupt fucosylation sites (e.g., mutations at N297, such as N297Q or N297A, to disrupt the formation of glycans that can contain a core fucose moiety), but it is generally preferred to maintain N297 and its glycans, such as by expressing the antibody or antigen-binding fragment in a host cell that has been genetically engineered to lack the ability (or have inhibited or impaired ability) to fucosylate the antibody or antigen-binding fragment; by expressing the antibody or antigen-binding fragment under conditions in which the host cell's ability to fucosylate the polypeptide is impaired (e.g., in the presence of 2-fluoro-L-fucose (2FF)); and the like. A defucosylated antibody or antigen-binding fragment may contain no, or substantially no, fucose moieties, and / or may be expressed by a host cell that has been genetically engineered to lack the ability (or have an inhibited or impaired ability) to fucosylate the antibody or antigen-binding fragment, and / or may be expressed under conditions where the host cell's ability to fucosylate the antibody or antigen-binding fragment is impaired (e.g., in the presence of 2-fluoro-L-fucose (2FF)). In some embodiments, the antibody or antigen-binding fragment does not contain a core fucose moiety at Asn297. In some embodiments, the defucosylated antibody or antigen-binding fragment has increased binding to FcγRIIIA. In some contexts, adding 2FF to a culture medium containing host cells expressing the antibody results in about 85% or more of the antibodies or antigen-binding fragments being free of fucose moieties. Thus, when a plurality of antibodies or antigen-binding fragments are produced in the presence of 2FF or a similar reagent, the plurality of antibodies or antigen-binding fragments may be described as "defucosylated." In some contexts, a plurality of antibodies or antigen-binding fragments may be described as, for example, defucosylated, meaning that about 85% or more of the individual antibody or antigen-binding fragment molecules in the plurality do not contain a fucose moiety. In certain preferred embodiments, the defucosylated antibody or antigen-binding fragment, or a population or plurality of defucosylated antibodies or antigen-binding fragments thereof, comprises asparagine (N) at EU position 297. Fucosylation or the lack thereof can be assessed using, for example, mass spectrometry (e.g., electrospray ionization mass spectrometry (ESI-MS)).In some embodiments, a plurality of compositions comprising any one or more of the presently disclosed antibodies or antigen-binding fragments are provided, wherein the composition comprises a defucosylated antibody or antigen-binding fragment.

[0309] In certain embodiments, the presently disclosed variants of IgG Fc polypeptides or fragments thereof have one or more functions that are different from (e.g., improved compared to) the corresponding function of a reference Fc polypeptide comprising one or more of the following mutations: G236A; G236S; G236A_A330L_I332E; G236A_A330L_I332E_M428L_N434S; A330L_I332E; or G236A_S239D_A330L_I332E. For example, in certain embodiments, the presently disclosed variants of IgG Fc polypeptides or fragments thereof have one or more of the following properties compared to a reference Fc polypeptide comprising one or more of the following mutations: G236A; G236S; G236A_A330L_I332E; G236A_A330L_I332E_M428L_N434S; A330L_I332E; or G236A_S239D_A330L_I332E: increased binding (e.g., affinity) to and / or signaling through human FcγRIIa H131; increased binding (e.g., affinity) to and / or signaling through human FcγRIIa H131; increased binding (e.g., affinity) to and / or signaling through human FcγRIIa R131; R131; decreased binding (e.g., affinity) to and / or signaling through human FcγRIIb; increased ratio of binding (e.g., affinity) to and / or signaling through human FcγRIIa (H131, R131, or both) relative to binding to or signaling through human FcγRIIb (respectively); increased binding to or signaling through human FcγRIIIa (V158, F158, or both); ) and / or signaling through human FcγRIIIa (V158, F158, or both); increased binding (e.g., affinity) to human C1q; higher Tm; improved production titer; improved signaling through FcγRIIa (H131, R131, or both) in host cells; increased promotion of ADCP and / or ADCC by human NK cells and / or human PBMCs in the presence of antigen-presenting cells; and improved ability to stimulate moDCs when forming immune complexes with antigen.

[0310] In the present disclosure, the binding of a variant Fc polypeptide or fragment can be described as increased (or "greater than," etc.) or decreased (or "decreased," "less than," etc.) compared to the binding of a comparator (e.g., a reference wild-type IgG1 Fc, or a reference IgG1 Fc that is wild-type except for the M428L and N434S mutations or except for the M428L and N434A mutations, or a variant IgG1 Fc comprising the G236A_A330L_I332E mutation) to the same binding partner. The binding interaction between the variant Fc polypeptide or fragment (or an antibody or polypeptide comprising the same) and a binding partner (e.g., human FcγR, FcRn, or C1q) can preferably be determined using an electrochemiluminescence assay, more preferably using the Meso Scale Discovery ("MSD"; mesoscale.com) platform. The MSD binding assay is similar to an ELISA, but MSD uses electrochemiluminescence rather than colorimetry as a detection technique. Other techniques for measuring binding interactions are known and include, for example, ELISA, surface plasmon resonance (SPR), biolayer interferometry (BLI), and the like.

[0311] In some embodiments, binding includes affinity, avidity, or both. Avidity refers to the strength of the bond between a binding molecule and its binding partner. In some contexts, binding can include affinity and / or avidity. Unless otherwise indicated, avidity refers to the overall binding strength of a molecule to a binding partner and reflects binding affinity, the potency of the binding site (e.g., whether an Fc polypeptide comprises one, two, or more binding sites), and, for example, the presence of another agent that may affect binding (e.g., a non-competitive inhibitor of an Fc polypeptide).

[0312] The binding interaction between the variant molecules of the present disclosure and the binding partner can be expressed as a fold change relative to the binding interaction between the reference molecule and the binding partner. For example, the binding of the currently disclosed antibodies comprising a variant Fc to human FcγRIIa may be stronger than the binding of an antibody comprising a wild-type Fc to human FcγRIIa, and the relative increased strength of the variant can be expressed as a fold change (e.g., a linear scale of the area under the curve) relative to the binding of the reference molecule using the same assay. For example, the variant Fc polypeptide or fragment binds to FcγRIIa with a binding strength that is 2-fold, 3-fold, 4-fold, or 5-fold greater than that of the reference Fc polypeptide or fragment to FcγRIIa. As another example, the variant Fc polypeptide or fragment thereof may bind to FcγRIIb with a weaker strength compared to the reference Fc or its fragment; for example, it may have 0.9-fold binding, 0.8-fold binding, 0.7-fold binding, 0.6-fold binding, etc. compared to the reference Fc polypeptide or its fragment. It will be understood that, for example, the expression "2-fold greater binding compared to the binding of a reference" means a 2-fold increase in binding compared to the reference.

[0313] Furthermore, the binding of a variant Fc molecule of the present disclosure to two different partner molecules can be described as a ratio, and this ratio can be compared to a similar ratio obtained using the same assay with a reference molecule. For example, a variant Fc polypeptide may bind to human FcγRIIa H131 five times as strongly as it binds to human FcγRIIb, while a reference wild-type Fc polypeptide binds to FcγRIIa H131 as strongly as it binds to human FcγRIIb. In this example, the variant Fc polypeptide can be said to have a 5:1 (bound to FcγRIIIa H131:bound to FcγRIIb) binding ratio, which can be compared to a 1:1 (bound to FcγRIIIa H131:bound to FcγRIIb) binding ratio for the reference wild-type Fc polypeptide.

[0314] Variant Fc molecules of the present disclosure can also be described in terms of their ability to induce signaling in a host cell, wherein the host cell expresses or overexpresses one or more FcγRs (e.g., FcγRIIa H131, FcγRIIa R131, FcγRIIb, FcγRIIIa F158, or FcγRIIIa V158), and signaling is induced by binding of the variant molecule to the FcγR. Reporter cells useful for determining signaling include, for example, cells in which NF AT drives expression of a luciferase reporter gene (e.g., cells that can be obtained from get).

[0315] Unless otherwise indicated, FcγRs, FcRn, and C1q as described herein are human.

[0316] In some embodiments, the antibody or antigen-binding fragment comprising a variant Fc polypeptide or fragment is preferably capable of inducing one or more of: antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP); and complement-dependent cytotoxicity. Assays for measuring these functions are known.

[0317] In some embodiments, the variant Fc polypeptide or fragment (or antibody or antigen-binding fragment comprising the same) preferably has comparable binding to human FcRn (e.g., at pH 6.0) and / or comparable half-life in vivo in a mammal compared to a reference Fc polypeptide, fragment, antibody, or antigen-binding fragment, respectively.

[0318] In some embodiments, the variant Fc polypeptide or fragment (or antibody or antigen-binding fragment comprising the same) preferably has increased binding to human FcRn (e.g., at pH 6.0) and / or increased half-life in vivo in a mammal compared to a reference Fc polypeptide, fragment, antibody, or antigen-binding fragment, respectively.

[0319] In some embodiments, the melting temperature (Tm) of the variant Fc polypeptide or fragment (or antibody or antigen-binding fragment comprising the same) is preferably less than 12°C, less than 11°C, less than 10°C, less than 9°C, less than 8°C, less than 7°C, less than 6°C, less than 5°C, less than 4°C, less than 3°C, less than 2°C, or less than 1°C lower than the Tm of the reference Fc polypeptide (or antibody or antigen-binding fragment comprising the same), or the Tm is higher than the Tm of the reference Fc polypeptide or fragment (or polypeptide or antibody comprising the same). In some embodiments, the reference polypeptide or fragment is or comprises a wild-type human Fc polypeptide (or antibody comprising the same).

[0320] In some embodiments, the melting temperature of the variant Fc polypeptide or fragment (or antibody or antigen-binding fragment comprising the same) is higher than the melting temperature of the reference Fc polypeptide or fragment (or antibody or antigen-binding fragment comprising the same) comprising the mutations G236A, A330L, I332E, and optionally M428L and N434S.

[0321] In some embodiments, the variant Fc polypeptide or fragment (or antibody or antigen-binding fragment comprising the same) is preferably capable of being produced in a host cell line (e.g., a CHO cell line) at least about as efficiently (e.g., producing at least about the same titer and / or within less than 0.1-fold, less than 0.09-fold, less than 0.08-fold, less than 0.07-fold, less than 0.06-fold, less than 0.05-fold, less than 0.04-fold, less than 0.03-fold, less than 0.02-fold, or less than 0.02-fold) as a reference Fc polypeptide or fragment (or an antibody or antigen-binding fragment comprising the same).

[0322] In certain embodiments, the anti-NA antibodies or antigen-binding fragments of the present disclosure comprise a variant of (i) an IgG CH2 polypeptide or (ii) an IgG Fc polypeptide or fragment thereof, wherein the variant comprises an alanine (A) at EU position 236, a valine (V) at EU position 328, and a glutamic acid (E) at EU position 295. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GALVQE"). In some embodiments, the antibody or antigen-binding fragment further comprises the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0323] In certain other embodiments, the anti-NA antibodies or antigen-binding fragments of the present disclosure comprise a variant of: (i) an IgG hinge-CH2 polypeptide; or (ii) an IgG hinge-Fc polypeptide or fragment thereof, wherein the variant comprises an alanine (A) at EU position 236, an alanine (A) at EU position 230, and a glutamic acid (E) at EU position 295. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GAPAQE"). In some embodiments, the antibody or antigen-binding fragment further comprises the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0324] In certain other embodiments, the anti-NA antibodies or antigen-binding fragments of the present disclosure comprise a variant of an IgG Fc polypeptide or fragment thereof, wherein the variant comprises an alanine (A) at EU position 236, a proline (P) at EU position 292, and an asparagine (N) at EU position 377. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GARPIN"). In some embodiments, the antibody or antigen-binding fragment further comprises the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0325] In certain other embodiments, the anti-NA antibody or antigen-binding fragment comprises a variant of (i) an IgG CH2 polypeptide or (ii) an IgG Fc polypeptide or fragment thereof, wherein the variant comprises an alanine (A) at EU position 236, an alanine (A) at EU position 334, and a glutamic acid (E) at EU position 295. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GAKAQE"). In some embodiments, the antibody or antigen-binding fragment further comprises the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0326] In certain other embodiments, the anti-NA antibodies or antigen-binding fragments of the present disclosure comprise a variant of (i) an IgG CH2 polypeptide or (ii) an IgG Fc polypeptide or fragment thereof, wherein the variant comprises a serine (S) at EU position 236, a proline (P) at EU position 292, and a leucine (L) at EU position 300. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GSRPYL"). In some embodiments, the antibody or antigen-binding fragment further comprises the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0327] In certain other embodiments, the anti-NA antibodies or antigen-binding fragments of the present disclosure comprise a variant of (i) an IgG CH2 polypeptide or (ii) an IgG Fc polypeptide or fragment thereof, wherein the variant comprises an alanine (A) at EU position 236, a proline (P) at EU position 292, and a leucine (L) at EU position 300. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GARPYL"). In some embodiments, the antibody or antigen-binding fragment further comprises the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0328] In certain other embodiments, the anti-NA antibodies or antigen-binding fragments of the present disclosure comprise a variant of: (i) an IgG CH2 polypeptide or (ii) an IgG Fc polypeptide or fragment thereof, wherein the variant comprises an alanine (A) at EU position 236 and a leucine (L) at EU position 300. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GAYL"). In some embodiments, the antibody or antigen-binding fragment further comprises the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0329] In certain other embodiments, the anti-NA antibodies or antigen-binding fragments of the present disclosure comprise a variant of: (i) an IgG CH2 polypeptide; or (ii) an IgG Fc polypeptide or fragment thereof, wherein the variant comprises an alanine (A) at EU position 236, an aspartic acid (D) at EU position 239, and a glutamic acid (E) at EU position 268. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GASDHE"). In some embodiments, the antibody or antigen-binding fragment further comprises the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein. In certain embodiments, the antibody or antigen-binding fragment is defucosylated.

[0330] In some embodiments, the antibody or antigen-binding fragment has increased binding to human FcγRIIa and / or has decreased binding to human FcγRIIb compared to the binding of a reference antibody or antigen-binding fragment to human FcγRIIa or human FcγRIIb, respectively, wherein binding is optionally determined using an electrochemiluminescence assay, further optionally using a Meso Scale Discovery.

[0331] In certain embodiments, the increased binding to human FcγRIIa comprises greater than 1-fold, at least 2-fold, at least 3-fold, at least 4-fold, at least 5-fold, at least 6-fold, at least 7-fold, at least 8-fold, at least 9-fold, or at least 10-fold greater binding to human FcγRIIa compared to binding of a reference antibody or antigen-binding fragment (optionally comprising a wild-type human IgG (e.g., IgG1) Fc polypeptide or fragment thereof) to human FcγRIIa.

[0332] In some embodiments, the human FcγRIIa comprises H131, and optionally the increased binding to human FcγRIIa H131 comprises at least 4-fold, at least 5-fold, at least 6-fold, at least 7-fold, at least 8-fold, at least 9-fold, or at least 10-fold greater binding to human FcγRIIa H131 compared to binding of a reference antibody or antigen-binding fragment (optionally comprising a wild-type human IgG (e.g., IgG1) Fc polypeptide or fragment thereof) to human FcγRIIa H131.

[0333] In some embodiments, the human FcγRIIa comprises R131, and optionally the increased binding to human FcγRIIa R131 comprises greater than 1-fold, at least 2-fold, at least 3-fold, at least 4-fold, at least 5-fold, at least 6-fold, at least 7-fold, at least 8-fold, at least 9-fold, or at least 10-fold greater binding to human FcγRIIa R131 compared to binding of a reference antibody or antigen-binding fragment (optionally comprising a wild-type human IgG (e.g., IgG1) Fc polypeptide or fragment thereof) to human FcγRIIa R131.

[0334] In some embodiments, the reduced binding to human FcγRIIb comprises less than 0.9-fold, less than 0.8-fold, less than 0.7-fold, less than 0.6-fold, or between 0.5-fold and 0.9-fold the binding of a reference antibody or antigen-binding fragment (optionally comprising a wild-type human IgG (e.g., IgG1) Fc polypeptide or fragment thereof) to human FcγRIIb.

[0335] In any of the presently disclosed embodiments, (1) the ratio of binding of the antibody or antigen-binding fragment to human FcγRIIa relative to (ii) the binding of the antibody or antigen-binding fragment to human FcγRIIb is greater than (2) the ratio of binding of the reference polypeptide to human FcγRIIa relative to (iv) the binding of the reference antibody or antigen-binding fragment to human FcγRIIb, wherein the reference antibody or antigen-binding fragment optionally comprises a wild-type human IgG (e.g., IgG1) Fc polypeptide or fragment thereof, wherein binding is optionally determined using an electrochemiluminescence assay, further optionally using Meso Scale Discovery. In some embodiments, human FcγRIIa comprises H131, R131, or both. In some embodiments, the ratio in (1) is greater than the ratio in (2) by more than 1 fold, at least 2 fold, at least 3 fold, at least 4 fold, at least 5 fold, at least 6 fold, at least 7 fold, at least 8 fold, at least 9 fold, at least 10 fold, at least 11 fold, at least 12 fold, at least 13 fold, or at least 14 fold.

[0336] Also provided are anti-NA antibodies or antigen-binding fragments of the present disclosure comprising a variant of: (i) an IgG CH2 polypeptide or (ii) an IgG Fc polypeptide or fragment thereof, wherein the variant comprises an alanine (A) at EU position 236 and a leucine (L) at EU position 300. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GAYL"). In certain additional embodiments, the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein, are present. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0337] In some embodiments, the antibody or antigen-binding fragment has increased binding to human FcγRIIa compared to binding of a reference antibody or antigen-binding fragment to human FcγRIIa, wherein binding is optionally determined using an electrochemiluminescence assay, further optionally using Meso Scale Discovery.

[0338] In some embodiments, the increased binding to human FcγRIIa comprises at least 4-fold, at least 5-fold, at least 6-fold, at least 7-fold, at least 8-fold, at least 9-fold, at least 10-fold, at least 11-fold, at least 12-fold, at least 13-fold, at least 14-fold, at least 15-fold, at least 16-fold, at least 17-fold, or at least 18-fold greater binding to human FcγRIIa compared to binding of a reference antibody or antigen-binding fragment (optionally comprising a wild-type human IgG (e.g., IgG1) Fc polypeptide or fragment thereof) to human FcγRIIa.

[0339] In some embodiments, the human FcγRIIa comprises H131, and optionally the increased binding to human FcγRIIa H131 comprises at least 4-fold, at least 5-fold, at least 6-fold, at least 7-fold, at least 8-fold, at least 9-fold, or at least 10-fold, at least 11-fold, at least 12-fold, at least 13-fold, at least 14-fold, at least 15-fold, at least 16-fold, at least 17-fold, or at least 18-fold greater binding to human FcγRIIa H131 compared to binding of a reference antibody or antigen-binding fragment (optionally comprising a wild-type human IgG (e.g., IgG1) Fc polypeptide or fragment thereof) to human FcγRIIa H131.

[0340] In some embodiments, the human FcγRIIa comprises R131, and optionally, the increased binding to human FcγRIIa R131 comprises at least 4-fold greater binding to human FcγRIIa R131 compared to binding of a reference antibody or antigen-binding fragment (optionally comprising a wild-type human IgG (e.g., IgG1) Fc polypeptide or fragment thereof) to human FcγRIIa R131.

[0341] In certain embodiments, the ratio of (1) (i) binding of the antibody or antigen-binding fragment to human FcγRIIa relative to (ii) binding of the antibody or antigen-binding fragment to human FcγRIIb is greater than the ratio of (2) (iii) binding of a reference antibody or antigen-binding fragment to human FcγRIIa relative to (iv) binding of a reference polypeptide to human FcγRIIb, wherein the reference antibody or antigen-binding fragment comprises a wild-type human IgG Fc polypeptide or fragment thereof. In certain embodiments, human FcγRIIa comprises H131, R131, or both. In further embodiments, the ratio in (1) is at least 4-fold, at least 5-fold, at least 6-fold, at least 7-fold, at least 8-fold, at least 9-fold, at least 10-fold, at least 11-fold, at least 12-fold, at least 13-fold, at least 14-fold, at least 15-fold, at least 16-fold, or at least 17-fold greater than the ratio in (2).

[0342] Also provided are anti-NA antibodies or antigen-binding fragments of the present disclosure comprising a variant of: (i) an IgG CH2 polypeptide or (ii) an IgG Fc polypeptide or fragment thereof, wherein the variant comprises an alanine (A) at EU position 236, a proline (P) at EU position 292, and a leucine (L) at EU position 300. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GARPYL"). In certain additional embodiments, the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein, are present. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0343] In certain embodiments, the antibody or antigen-binding fragment has increased binding to human FcγRIIIa compared to binding of a reference antibody or antigen-binding fragment to human FcγRIIIa, wherein binding is optionally determined using an electrochemiluminescence assay, further optionally using Meso Scale Discovery.

[0344] In some embodiments, the increased binding to human FcγRIIa comprises at least 2-fold, at least 3-fold, at least 4-fold, at least 5-fold, at least 6-fold, at least 7-fold, at least 8-fold, at least 9-fold, at least 10-fold, at least 11-fold, at least 12-fold, at least 13-fold, or at least 14-fold greater binding to human FcγRIIa compared to binding of a reference antibody or antigen-binding fragment, optionally comprising a wild-type human IgG Fc polypeptide or fragment thereof.

[0345] In some embodiments, the human FcγRIIa comprises H131, and optionally the increased binding to human FcγRIIa H131 comprises at least 2-fold, at least 3-fold, at least 4-fold, at least 5-fold, at least 6-fold, at least 7-fold, at least 8-fold, at least 9-fold, at least 10-fold, at least 11-fold, at least 12-fold, at least 13-fold, or at least 14-fold greater binding to human FcγRIIa H131 compared to binding of a reference antibody or antigen-binding fragment optionally comprising a wild-type human IgG Fc polypeptide or fragment thereof.

[0346] In some embodiments, the human FcγRIIa comprises R131, and optionally, the increased binding to human FcγRIIa H131 comprises at least 2-fold greater binding to human FcγRIIa R131 compared to binding of a reference antibody or antigen-binding fragment optionally comprising a wild-type human IgG Fc polypeptide or fragment thereof to human FcγRIIa R131.

[0347] In certain embodiments, the ratio of (1) (i) binding of the antibody or antigen-binding fragment to human FcγRIIa relative to (ii) binding of the antibody or antigen-binding fragment to human FcγRIIb is greater than the ratio of (2) (iii) binding of a reference antibody or antigen-binding fragment to human FcγRIIa relative to (iv) binding of a reference antibody or antigen-binding fragment to human FcγRIIb, wherein the reference antibody or antigen-binding fragment optionally comprises a wild-type human IgG Fc polypeptide or fragment thereof, wherein binding is optionally determined using an electrochemiluminescence assay, further optionally using Meso Scale Discovery. In some embodiments, human FcγRIIa comprises H131, R131, or both. In some embodiments, the ratio in (1) is at least 2-fold, at least 3-fold, at least 4-fold, at least 5-fold, at least 6-fold, at least 7-fold, at least 8-fold, at least 9-fold, at least 10-fold, at least 11-fold, at least 12-fold, at least 13-fold, at least 14-fold, or at least 15-fold greater than the ratio in (2).

[0348] In certain embodiments, the antibody or antigen-binding fragment has increased binding to human FcγRIIIa compared to binding of a reference antibody or antigen-binding fragment to human FcγRIIIa, wherein binding is optionally determined using an electrochemiluminescence assay, further optionally using Meso Scale Discovery. In some embodiments, the human FcγRIII comprises V158, F158, or both. In certain additional embodiments, the increased binding to human FcγRIIIa comprises greater than 2-fold, at least 2.1-fold, at least 2.2-fold, at least 2.3-fold, at least 2.4-fold, at least 2.5-fold, at least 2.6-fold, at least 2.7-fold, at least 2.8-fold, at least 2.9-fold, at least 3.0-fold, at least 3.1-fold, at least 3.2-fold, at least 3.3-fold, at least 3.4-fold, at least 3.5-fold, at least 3.6-fold, or at least 3.7-fold greater binding to human FcγRIIIa compared to binding of a reference antibody or antigen-binding fragment, optionally comprising a wild-type human IgG Fc polypeptide or fragment thereof.

[0349] In certain embodiments, the antibody or antigen-binding fragment is capable of binding to human complement component 1q (CIq), wherein binding is optionally determined using an electrochemiluminescence assay, further optionally using Meso Scale Discovery.

[0350] Also provided are anti-NA antibodies or antigen-binding fragments of the present disclosure comprising a variant of an IgG Fc polypeptide, wherein the variant comprises a serine (S) at EU position 236, a valine (V) at EU position 420, a glutamic acid (E) at EU position 446, and a threonine (T) at EU position 309. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GSGVGELT"). In certain additional embodiments, the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein, are present. In certain embodiments, the antibody or antigen-binding fragment is defucosylated.

[0351] Also provided are anti-NA antibodies or antigen-binding fragments of the present disclosure comprising a variant of: (i) an IgG CH2 polypeptide or (ii) an IgG Fc polypeptide, wherein the variant comprises an alanine (A) at EU position 236 and a proline (P) at EU position 292. In some embodiments, the antibody or antigen-binding fragment comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GARP"). In certain additional embodiments, the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein, are present. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0352] In certain embodiments, the antibody or antigen-binding fragment has reduced binding to human FcγRIIb compared to binding of a reference antibody or antigen-binding fragment to human FcγRIIb, wherein binding is optionally determined using an electrochemiluminescence assay, further optionally using Meso Scale Discovery. In some embodiments, reduced binding to human FcγRIIb comprises less than 0.9-fold, less than 0.8-fold, less than 0.7-fold, less than 0.6-fold, less than 0.5-fold, or less than 0.4-fold compared to binding of a reference antibody or antigen-binding fragment, optionally comprising a wild-type human IgG Fc polypeptide or fragment thereof, to human FcγRIIb.

[0353] In further embodiments, the antibody or antigen-binding fragment has increased binding to human FcγRIIa compared to binding of a reference antibody or antigen-binding fragment to human FcγRIIa, wherein binding is optionally determined using an electrochemiluminescence assay, further optionally using Meso Scale Discovery.

[0354] In some embodiments, the increased binding to human FcγRIIa comprises greater than 1-fold, at least 2-fold, at least 3-fold, at least 4-fold, or at least 5-fold greater binding to human FcγRIIa compared to binding of a reference antibody or antigen-binding fragment comprising a wild-type human IgG Fc polypeptide or fragment thereof to human FcγRIIa.

[0355] In certain embodiments, human FcyRIIa comprises H131, R131, or both.

[0356] In some embodiments, the ratio of (1) (i) binding of the antibody or antigen-binding fragment to human FcγRIIa relative to (ii) binding of the antibody or antigen-binding fragment to human FcγRIIb is greater than the ratio of (2) (iii) binding of the antibody or antigen-binding fragment to human FcγRIIa relative to (iv) binding of a reference antibody or antigen-binding fragment to human FcγRIIb, wherein the reference antibody or antigen-binding fragment optionally comprises a wild-type human IgG Fc polypeptide or fragment thereof, wherein binding is optionally determined using an electrochemiluminescence assay, further optionally using Meso Scale Discovery. In some embodiments, human FcγRIIa comprises H131, R131, or both. In certain embodiments, the ratio in (1) is at least 2-fold, at least 3-fold, at least 4-fold, at least 5-fold, at least 6-fold, at least 7-fold, at least 8-fold, at least 10-fold, at least 11-fold, or at least 12-fold greater than the ratio in (2).

[0357] Also provided are anti-NA antibodies or antigen-binding fragments of the present disclosure comprising a variant of (i) an IgG CH2 polypeptide or (ii) an IgG Fc polypeptide, wherein the variant comprises a proline (P) at EU position 292 and a leucine (L) at EU position 300, and wherein the variant, and further optionally the antibody or antigen-binding fragment, has increased binding to human FcγRIIIa compared to binding of a reference antibody or antigen-binding fragment to human FcγRIIIa, wherein binding is optionally determined using an electrochemiluminescence assay, further optionally using a Meso Scale Discovery. In some embodiments, the antibody or antigen-binding fragment comprises (e.g., an otherwise wild-type) IgG1 CH2 polypeptide or IgG Fc polypeptide ("RPYL"). In certain additional embodiments, the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein, are present. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0358] In certain embodiments, the human FcγRIIIa comprises V158, F158, or both, and wherein the increased binding to human FcγRIIIa comprises at least 4-fold, at least 4.5-fold, at least 5-fold, at least 5.1-fold, or at least 5.2-fold greater binding compared to binding of a reference antibody or antigen-binding fragment, optionally comprising a wild-type human IgG Fc polypeptide or fragment thereof, to human FcγRIIa.

[0359] Also provided are anti-NA antibodies or antigen-binding fragments of the present disclosure comprising a variant of (i) an IgG CH2 polypeptide or (ii) an IgG Fc polypeptide or fragment thereof, wherein the variant comprises a leucine (L) at EU position 300. In some embodiments, the IgG CH2 polypeptide or IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("YL"). In certain additional embodiments, the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein, are present. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0360] Also provided are anti-NA antibodies or antigen-binding fragments of the present disclosure comprising a variant of an IgG Fc polypeptide or fragment thereof, wherein the variant comprises a lysine (K) at EU position 345, a serine (S) at EU position 236, a tyrosine (Y) at EU position 235, and a glutamic acid (E) at EU position 267. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GSEKLYSE"). In certain additional embodiments, the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein, are present. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0361] Also provided are anti-NA antibodies or antigen-binding fragments of the present disclosure comprising a variant of (i) an IgG hinge-CH2 polypeptide or (ii) an IgG hinge-Fc polypeptide or fragment thereof, wherein the variant comprises an arginine (R) at EU position 272, a threonine (T) at EU position 309, a tyrosine (Y) at EU position 219, and a glutamic acid (E) at EU position 267. In some embodiments, the IgG hinge-CH2 polypeptide or IgG hinge-Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 hinge-CH2 polypeptide or IgG hinge-Fc polypeptide or fragment thereof ("SYSEERLT"). In certain additional embodiments, the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein, are present. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0362] Also provided are anti-NA antibodies or antigen-binding fragments of the present disclosure comprising a variant of: (i) an IgG CH2 polypeptide or (ii) an IgG Fc polypeptide or fragment thereof, wherein the variant comprises a tyrosine (Y) at EU position 236. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GY"). In certain additional embodiments, the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein, are present. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0363] Also provided are anti-NA antibodies or antigen-binding fragments of the present disclosure comprising a variant of (i) an IgG CH2 polypeptide or (ii) an IgG Fc polypeptide or fragment thereof, wherein the variant comprises a tryptophan (W) at EU position 236. In some embodiments, the IgG CH2 polypeptide or (ii) an IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 CH2 polypeptide or Fc polypeptide or fragment thereof ("GW"). In certain additional embodiments, the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein, are present. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

[0364] Also provided are anti-NA antibodies or antigen-binding fragments of the present disclosure comprising a variant of (i) an IgG CH2 polypeptide or (ii) an IgG Fc polypeptide or fragment thereof, wherein the variant comprises an alanine (A) at EU position 236, wherein the IgG Fc polypeptide or fragment thereof and optionally the polypeptide is defucosylated, and wherein further optionally, the variant comprises a leucine (L) at EU position 330 and a glutamic acid (E) at EU position 332, wherein further optionally, the variant does not comprise an aspartic acid (D) at EU position 239, and even further optionally, comprises a serine (S) at EU position 239. In some embodiments, the IgG CH2 polypeptide or (ii) IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 CH2 polypeptide or Fc polypeptide or fragment thereof ("GA-afuc" or "GAALIE-afuc," respectively). In certain further embodiments, mutations M428L and N434S or mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein, are present.

[0365] Also provided are anti-NA antibodies or antigen-binding fragments of the present disclosure comprising a variant of an IgG Fc polypeptide or fragment thereof, wherein the variant comprises a leucine (L) at EU position 243, a glutamic acid (E) at EU position 446, a leucine (L) at EU position 396, and a glutamic acid (E) at EU position 267. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("FLSEPLGE"). In certain additional embodiments, the mutations M428L and N434S or the mutations M428L and N434A or any other mutation that enhances binding to human FcRn, such as those described herein, are present. In certain embodiments, the antibody or antigen-binding fragment is defucosylated.

[0366] Also provided is an anti-NA antibody or antigen-binding fragment comprising a variant of (i) an IgG CH2 polypeptide or (ii) an IgG Fc polypeptide or fragment thereof, wherein the variant comprises an alanine (A) at EU position 236, an aspartic acid (D) at EU position 239, a glutamic acid (E) at EU position 332, a leucine (L) at EU position 428, and a serine (S) or alanine (A) at EU position 434. In some embodiments, the IgG Fc polypeptide or fragment thereof comprises (e.g., an otherwise wild-type) IgG1 Fc polypeptide or fragment thereof ("GASDIEMLNS" or "GASDIEMLNA").

[0367] In some embodiments, an antibody or antigen-binding fragment of the present disclosure comprises a variant of an (e.g., IgG1) IgG Fc polypeptide, wherein the variant comprises the following mutations according to EU numbering: (i) M428L, N434S, G236A, L328V, and Q295E; (ii) M428L, N434S, G236A, R292P, and I377N; (iii) M428L, N434S, G236A, and Y300L; (iv) M428L, N434S, G236A, R292P, and Y300L; (v) M428L, N434S, G236A, L328V, and Q295E; 295E, wherein the antibody or antigen-binding fragment is afucosylated; (vi) M428L, N434S, G236A, R292P and I377N, wherein the antibody or antigen-binding fragment is afucosylated; (vii) M428L, N434S, G236A and Y300L, wherein the antibody or antigen-binding fragment is afucosylated; or (viii) M428L, N434S, G236A, R292P and Y300L, wherein the antibody or antigen-binding fragment is afucosylated. In some embodiments, the (e.g., IgG1) variant of the IgG Fc polypeptide comprises an amino acid replacement consisting essentially of the replacement mutations in (i), (ii), (iii), (iv), (v), (vi), (vii) or (viii) above. In some embodiments, the antibody or antigen-binding fragment comprises a kappa light chain.

[0368] In some embodiments, an antibody or antigen-binding fragment of the present disclosure comprises a variant of an (e.g., IgG1) IgG Fc polypeptide, wherein the variant comprises the following mutations according to EU numbering: (i) M428L, N434A, G236A, L328V, and Q295E; (ii) M428L, N434A, G236A, R292P, and I377N; (iii) M428L, N434A, G236A, and Y300L; (iv) M428L, N434A, G236A, R292P, and Y300L; (v) M428L, N434A, G236A, L328V, and Q295E; In some embodiments, the IgG Fc polypeptide variant comprises an amino acid substitution consisting essentially of the substitution mutations in (i), (ii), (iii), (iv), (v), (vi), (vii), or (viii), wherein the antibody or antigen-binding fragment is afucosylated. In some embodiments, the antibody comprises a kappa light chain. In certain embodiments, the antibody or antigen-binding fragment is capable of eliciting sustained protection in a subject even when no detectable levels of the antibody or antigen-binding fragment are found in the subject (i.e., when the antibody or antigen-binding fragment has been cleared from the subject after administration). This protection is referred to herein as a vaccine effect. Without wishing to be bound by theory, it is believed that dendritic cells can internalize the complex of the antibody and antigen and then induce or contribute to an endogenous immune response to the antigen. In certain embodiments, the antibody or antigen-binding fragment comprises one or more modifications, such as, for example, mutations comprising G236A, A330L, and I332E in the Fc, which can activate dendritic cells that can induce, for example, T cell immunity to the antigen. In any of the embodiments disclosed herein, the antibody or antigen-binding fragment comprises an Fc polypeptide or fragment thereof, including CH2 (or a fragment thereof), CH3 (or a fragment thereof), or CH2 and CH3, wherein CH2, CH3, or both can be of any isotype and can contain amino acid substitutions or other modifications compared to the corresponding wild-type CH2 or CH3, respectively. In certain embodiments, the Fc of the present disclosure comprises two CH2-CH3 polypeptides that associate to form a dimer.

[0369] Non-limiting examples of heavy chain or Fc amino acid sequences - including certain sequences comprising amino acid substitution mutations as disclosed herein - are provided in SEQ ID NOs.: 69-95. In certain embodiments, the anti-NA antibodies or antigen-binding fragments of the present disclosure comprise a heavy chain comprising an amino acid sequence having at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity (or similarity) to an amino acid sequence set forth in any one of SEQ ID NOs.: 69-95, or an amino acid sequence comprising or consisting of an amino acid sequence set forth in any one of SEQ ID NOs.: 69-95.

[0370] In any embodiment of the presently disclosed embodiment, antibody or Fab can be monoclonal.As used herein, the term "monoclonal antibody" (mAb) refers to the antibody obtained from a substantially homogeneous antibody population, that is, except for the possible naturally occurring mutation that may exist (in some cases, a small amount of existence), the individual antibodies constituting the population are identical. Monoclonal antibodies are highly specific and are directed to a single antigenic site. In addition, in contrast to the polyclonal antibody preparations comprising different antibodies directed to different epitopes, each monoclonal antibody is directed to a single epitope of the antigen. In addition to their specificity, the advantage of monoclonal antibodies is that they can be synthesized without being contaminated by other antibodies. The term "monoclonal" should not be interpreted as needing to produce antibodies by any ad hoc method. For example, monoclonal antibodies that can be used for the present invention can be prepared by the hybridoma method described by Kohler et al., Nature 256:495 (1975), or recombinant DNA methods can be used to prepare in bacteria, eukaryotic animals or plant cells (see, for example, U.S. Patent number 4,816,567). Monoclonal antibodies can also be isolated from phage antibody libraries using techniques such as those described in Clackson et al., Nature, 352:624-628 (1991) and Marks et al., J. Mol. Biol., 222:581-597 (1991). Monoclonal antibodies can also be obtained using the methods disclosed in PCT Publication No. WO 2004 / 076677A2.

[0371] The antibodies and antigen-binding fragments disclosed herein include "chimeric antibodies," in which a portion of the heavy and / or light chain is identical or homologous to a corresponding sequence in an antibody derived from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chain is identical or homologous to a corresponding sequence in an antibody derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, as long as they exhibit the desired biological activity (see, U.S. Patent Nos. 4,816,567, 5,530,101, and 7,498,415; and Morrison et al., Proc. Natl. Acad. Sci. USA, 81: 6851-6855 (1984)). For example, a chimeric antibody may contain both human and non-human residues. In addition, a chimeric antibody may contain residues that are not found in the recipient antibody or the donor antibody. These modifications are made to further improve antibody performance. For more details, see Jones et al., Nature 321:522-525 (1986); Riechmann et al., Nature 332:323-329 (1988); and Presta, Curr. Op. Struct. Biol. 2:593-596 (1992). Chimeric antibodies also include primatized and humanized antibodies.

[0372] "Humanized antibodies" are generally considered to be human antibodies with one or more amino acid residues introduced therein from non-human sources. These non-human amino acid residues are generally taken from the variable domains. Humanization can be carried out according to the method of Winter and colleagues (Jones et al., Nature, 321: 522-525 (1986); Reichmann et al., Nature, 332: 323-327 (1988); Verhoeyen et al., Science, 239: 1534-1536 (1988)), specifically by replacing the corresponding sequence of a human antibody with a non-human variable sequence. Therefore, such "humanized" antibodies are chimeric antibodies (U.S. Patent Nos. 4,816,567; 5,530,101 and 7,498,415), in which substantially less than a complete human variable domain has been replaced by a corresponding sequence from a non-human species. In some cases, a "humanized" antibody is an antibody produced by a non-human cell or animal and comprising a human sequence (e.g., H1 domain).

[0373] "Human antibodies" are antibodies that contain only sequences present in antibodies produced by humans (i.e., sequences encoded by human antibody encoding genes). However, as used herein, human antibodies may include residues or modifications not found in naturally occurring human antibodies (e.g., antibodies isolated from humans), including those modifications and variant sequences described herein. These are generally made to further improve or enhance antibody performance. In some cases, human antibodies are produced by transgenic animals. For example, see U.S. Patent Nos. 5,770,429, 6,596,541, and 7,049,426.

[0374] In certain embodiments, the antibodies or antigen-binding fragments of the disclosure are chimeric, humanized, or human.

[0375] In some embodiments, pharmacokinetic ("PK") parameters are used to describe or characterize the antibodies or antigen-binding fragments provided herein. Details regarding collecting antibody serum concentrations for the purpose of assessing PK parameters are described in conjunction with the Examples herein. The term "t 1 / 2 " or "half-life" refers to the elimination half-life of an antibody or antigen-binding fragment contained in a pharmaceutical composition administered to a subject. The term "C 最后 ” generally refers to the last measurable plasma concentration (i.e., after which the substance is no longer present in plasma in measurable concentrations).

[0376] In some embodiments, the VH and VL of the antibody or antigen-binding fragment comprise the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 amino acid sequences of the VH and VL set forth in the following SEQ ID NOs. as determined by the IMGT numbering system or method: (i) 45 and 37, respectively; (ii) 46 and 37, respectively; (iii) 48 and 37, respectively; (iv) 50 and 37, respectively; (v) 52 and 37, respectively; (vi) 54 and 37, respectively; (vii) 56 and 37, respectively; (viii) 58 and 37, respectively; (ix) 60 and 37, respectively; (x) 63 and 37, respectively; (xi) 65 and 37, respectively; (xii) 45 and 66, respectively; (xiii) 46 and 37, respectively. 66; (xiv) 48 and 66 respectively; (xv) 50 and 66 respectively; (xvi) 52 and 66 respectively; (xvii) 54 and 66 respectively; (xviii) 56 and 66 respectively; (xix) 58 and 66 respectively; (xx) 60 and 66 respectively; (xxi) 63 and 66 respectively; (xxii) 65 and 66 respectively; (xxiii) 45 and 68 respectively; (xxiv) 46 and 68 respectively; (xxv) 48 and 68 respectively; (xxvi) 50 and 68 respectively; (xxvii) 52 and 68 respectively; (xxviii) 54 and 68 respectively; ( xxix) 56 and 68 respectively; (xxx) 58 and 68 respectively; (xxxi) 60 and 68 respectively; (xxxii) 63 and 68 respectively; (xxxiii) 65 and 68 respectively; (xxxiv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 8 respectively; (xxxv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 17 respectively; (xxxvi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 20 respectively; (xxxvii) 45 respectively , 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23, respectively; (xxxviii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 31, respectively; (xxxix) 2, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 37, respectively; (xxxx) 2, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 66, respectively; (xxxxi) 2, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 68, respectively;(xxxxii) 2, 14, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63, or 65 and 66, respectively; (xxxxiii) 2 and 8, respectively; or (xxxxiv) 2 and 37, respectively. In some embodiments, the CDRH3 and CDRL3 are defined according to IMGT. In some embodiments, the CDRH3 and CDRL3 are defined according to IMGT-linked.

[0377] In some embodiments, the VH and VL of the antibody or antigen-binding fragment comprise the amino acids in SEQ ID NO.The amino acid sequences of CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 of VH and VL listed in the table are as follows: (i) 45 and 37, respectively; (ii) 46 and 37, respectively; (iii) 48 and 37, respectively; (iv) 50 and 37, respectively; (v) 52 and 37, respectively; (vi) 54 and 37, respectively; (vii) 56 and 37, respectively; (viii) 58 and 37, respectively; (ix) 60 and 37, respectively; (x) 63 and 37, respectively; (xi) 65 and 37, respectively; (xii) 45 and 66, respectively; (xiii) 46 and 66, respectively; (xiv) 48 and 66, respectively; (xv) 50 and 66 respectively; (xvi) 52 and 66 respectively; (xvii) 54 and 66 respectively; (xviii) 56 and 66 respectively; (xix) 58 and 66 respectively; (xx) 60 and 66 respectively; (xxi) 63 and 66 respectively; (xxii) 65 and 66 respectively; (xxiii) 45 and 68 respectively; (xxiv) 46 and 68 respectively; (xxv) 48 and 68 respectively; (xxvi) 50 and 68 respectively; (xxvii) 52 and 68 respectively; (xxviii) 54 and 68 respectively; (xxix) 56 and 68 respectively; (xxx) 58 and 68 respectively; (xxxi) 60 and 68 respectively; ( xxxii) 63 and 68 respectively; (xxxiii) 65 and 68 respectively; (xxxiv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 8 respectively; (xxxv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 17 respectively; (xxxvi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 20 respectively; (xxxvii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23 respectively; (xxxviii) 45, 46, 48, 50, 52, 54, or 37, respectively.

[0378] In some embodiments, the VH and VL of the antibody or antigen-binding fragment comprise the amino acid sequence of SEQ ID NO.The amino acid sequences of CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 of VH and VL listed in the table are as follows: (i) 45 and 37, respectively; (ii) 46 and 37, respectively; (iii) 48 and 37, respectively; (iv) 50 and 37, respectively; (v) 52 and 37, respectively; (vi) 54 and 37, respectively; (vii) 56 and 37, respectively; (viii) 58 and 37, respectively; (ix) 60 and 37, respectively; (x) 63 and 37, respectively; (xi) 65 and 37, respectively; (xii) 45 and 66, respectively; (xiii) 46 and 66, respectively; (xiv) 48 and 66, respectively; (xv) 50 and 66 respectively; (xvi) 52 and 66 respectively; (xvii) 54 and 66 respectively; (xviii) 56 and 66 respectively; (xix) 58 and 66 respectively; (xx) 60 and 66 respectively; (xxi) 63 and 66 respectively; (xxii) 65 and 66 respectively; (xxiii) 45 and 68 respectively; (xxiv) 46 and 68 respectively; (xxv) 48 and 68 respectively; (xxvi) 50 and 68 respectively; (xxvii) 52 and 68 respectively; (xxviii) 54 and 68 respectively; (xxix) 56 and 68 respectively; (xxx) 58 and 68 respectively; (xxxi) 60 and 68 respectively; ( xxxii) 63 and 68 respectively; (xxxiii) 65 and 68 respectively; (xxxiv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 8 respectively; (xxxv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 17 respectively; (xxxvi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 20 respectively; (xxxvii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23 respectively; (xxxviii) 45, 46, 48, 50, 52, 54, or 37, respectively.

[0379] In some embodiments, the VH and VL of the antibody or antigen-binding fragment comprise the following sequences as determined by the Enhanced Chothia numbering system or method:The amino acid sequences of CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 of VH and VL listed in the table are as follows: (i) 45 and 37, respectively; (ii) 46 and 37, respectively; (iii) 48 and 37, respectively; (iv) 50 and 37, respectively; (v) 52 and 37, respectively; (vi) 54 and 37, respectively; (vii) 56 and 37, respectively; (viii) 58 and 37, respectively; (ix) 60 and 37, respectively; (x) 63 and 37, respectively; (xi) 65 and 37, respectively; (xii) 45 and 66, respectively; (xiii) 46 and 66, respectively; (xiv) 48 and 66, respectively; (xv) 50 and 66 respectively; (xvi) 52 and 66 respectively; (xvii) 54 and 66 respectively; (xviii) 56 and 66 respectively; (xix) 58 and 66 respectively; (xx) 60 and 66 respectively; (xxi) 63 and 66 respectively; (xxii) 65 and 66 respectively; (xxiii) 45 and 68 respectively; (xxiv) 46 and 68 respectively; (xxv) 48 and 68 respectively; (xxvi) 50 and 68 respectively; (xxvii) 52 and 68 respectively; (xxviii) 54 and 68 respectively; (xxix) 56 and 68 respectively; (xxx) 58 and 68 respectively; (xxxi) 60 and 68 respectively; ( xxxii) 63 and 68 respectively; (xxxiii) 65 and 68 respectively; (xxxiv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 8 respectively; (xxxv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 17 respectively; (xxxvi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 20 respectively; (xxxvii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23 respectively; (xxxviii) 45, 46, 48, 50, 52, 54, or 37, respectively.

[0380] In some embodiments, the VH and VL of the antibody or antigen-binding fragment comprise the following sequences as determined by the AHo numbering system or method:The amino acid sequences of CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 of VH and VL listed in the table are as follows: (i) 45 and 37, respectively; (ii) 46 and 37, respectively; (iii) 48 and 37, respectively; (iv) 50 and 37, respectively; (v) 52 and 37, respectively; (vi) 54 and 37, respectively; (vii) 56 and 37, respectively; (viii) 58 and 37, respectively; (ix) 60 and 37, respectively; (x) 63 and 37, respectively; (xi) 65 and 37, respectively; (xii) 45 and 66, respectively; (xiii) 46 and 66, respectively; (xiv) 48 and 66, respectively; (xv) 50 and 66 respectively; (xvi) 52 and 66 respectively; (xvii) 54 and 66 respectively; (xviii) 56 and 66 respectively; (xix) 58 and 66 respectively; (xx) 60 and 66 respectively; (xxi) 63 and 66 respectively; (xxii) 65 and 66 respectively; (xxiii) 45 and 68 respectively; (xxiv) 46 and 68 respectively; (xxv) 48 and 68 respectively; (xxvi) 50 and 68 respectively; (xxvii) 52 and 68 respectively; (xxviii) 54 and 68 respectively; (xxix) 56 and 68 respectively; (xxx) 58 and 68 respectively; (xxxi) 60 and 68 respectively; ( xxxii) 63 and 68 respectively; (xxxiii) 65 and 68 respectively; (xxxiv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 8 respectively; (xxxv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 17 respectively; (xxxvi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 20 respectively; (xxxvii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23 respectively; (xxxviii) 45, 46, 48, 50, 52, 54, or 37, respectively.

[0381] In some embodiments, the VH and VL of the antibody or antigen-binding fragment comprise the following sequences as determined by the Northern numbering system or method:The amino acid sequences of CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 of VH and VL listed in the table are as follows: (i) 45 and 37, respectively; (ii) 46 and 37, respectively; (iii) 48 and 37, respectively; (iv) 50 and 37, respectively; (v) 52 and 37, respectively; (vi) 54 and 37, respectively; (vii) 56 and 37, respectively; (viii) 58 and 37, respectively; (ix) 60 and 37, respectively; (x) 63 and 37, respectively; (xi) 65 and 37, respectively; (xii) 45 and 66, respectively; (xiii) 46 and 66, respectively; (xiv) 48 and 66, respectively; (xv) 50 and 66 respectively; (xvi) 52 and 66 respectively; (xvii) 54 and 66 respectively; (xviii) 56 and 66 respectively; (xix) 58 and 66 respectively; (xx) 60 and 66 respectively; (xxi) 63 and 66 respectively; (xxii) 65 and 66 respectively; (xxiii) 45 and 68 respectively; (xxiv) 46 and 68 respectively; (xxv) 48 and 68 respectively; (xxvi) 50 and 68 respectively; (xxvii) 52 and 68 respectively; (xxviii) 54 and 68 respectively; (xxix) 56 and 68 respectively; (xxx) 58 and 68 respectively; (xxxi) 60 and 68 respectively; ( xxxii) 63 and 68 respectively; (xxxiii) 65 and 68 respectively; (xxxiv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 8 respectively; (xxxv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 17 respectively; (xxxvi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 20 respectively; (xxxvii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23 respectively; (xxxviii) 45, 46, 48, 50, 52, 54, or 37, respectively.

[0382] In some embodiments, the VH and VL of the antibody or antigen-binding fragment comprise the following SEQ ID NO.The amino acid sequences of CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 of VH and VL listed in the table are as follows: (i) 45 and 37, respectively; (ii) 46 and 37, respectively; (iii) 48 and 37, respectively; (iv) 50 and 37, respectively; (v) 52 and 37, respectively; (vi) 54 and 37, respectively; (vii) 56 and 37, respectively; (viii) 58 and 37, respectively; (ix) 60 and 37, respectively; (x) 63 and 37, respectively; (xi) 65 and 37, respectively; (xii) 45 and 66, respectively; (xiii) 46 and 66, respectively; (xiv) 48 and 66, respectively; (xv) 50 and 66 respectively; (xvi) 52 and 66 respectively; (xvii) 54 and 66 respectively; (xviii) 56 and 66 respectively; (xix) 58 and 66 respectively; (xx) 60 and 66 respectively; (xxi) 63 and 66 respectively; (xxii) 65 and 66 respectively; (xxiii) 45 and 68 respectively; (xxiv) 46 and 68 respectively; (xxv) 48 and 68 respectively; (xxvi) 50 and 68 respectively; (xxvii) 52 and 68 respectively; (xxviii) 54 and 68 respectively; (xxix) 56 and 68 respectively; (xxx) 58 and 68 respectively; (xxxi) 60 and 68 respectively; ( xxxii) 63 and 68 respectively; (xxxiii) 65 and 68 respectively; (xxxiv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 8 respectively; (xxxv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 17 respectively; (xxxvi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 20 respectively; (xxxvii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23 respectively; (xxxviii) 45, 46, 48, 50, 52, 54, or 37, respectively.

[0383] In some embodiments, the VH and VL of the antibody or antigen-binding fragment comprise the sequences in SEQ ID NO.The amino acid sequences of CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 of VH and VL listed in the table are as follows: (i) 45 and 37, respectively; (ii) 46 and 37, respectively; (iii) 48 and 37, respectively; (iv) 50 and 37, respectively; (v) 52 and 37, respectively; (vi) 54 and 37, respectively; (vii) 56 and 37, respectively; (viii) 58 and 37, respectively; (ix) 60 and 37, respectively; (x) 63 and 37, respectively; (xi) 65 and 37, respectively; (xii) 45 and 66, respectively; (xiii) 46 and 66, respectively; (xiv) 48 and 66, respectively; (xv) 50 and 66 respectively; (xvi) 52 and 66 respectively; (xvii) 54 and 66 respectively; (xviii) 56 and 66 respectively; (xix) 58 and 66 respectively; (xx) 60 and 66 respectively; (xxi) 63 and 66 respectively; (xxii) 65 and 66 respectively; (xxiii) 45 and 68 respectively; (xxiv) 46 and 68 respectively; (xxv) 48 and 68 respectively; (xxvi) 50 and 68 respectively; (xxvii) 52 and 68 respectively; (xxviii) 54 and 68 respectively; (xxix) 56 and 68 respectively; (xxx) 58 and 68 respectively; (xxxi) 60 and 68 respectively; ( xxxii) 63 and 68 respectively; (xxxiii) 65 and 68 respectively; (xxxiv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 8 respectively; (xxxv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 17 respectively; (xxxvi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 20 respectively; (xxxvii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23 respectively; (xxxviii) 45, 46, 48, 50, 52, 54, or 37, respectively.

[0384] In some embodiments, an anti-influenza neuraminidase (anti-NA) antibody or antigen-binding fragment thereof is provided, comprising: (i) a heavy chain variable domain (VH) comprising a complementarity determining region (CDR) H1, CDRH2, and CDRH3, and (ii) a light chain variable domain (VL) comprising CDRL1, CDRL2, and CDRL3, wherein: (a) CDRH1 comprises or consists of the amino acid sequence set forth in SEQ ID NO.: 3, SEQ ID NO.: 47, SEQ ID NO.: 49, or SEQ ID NO.: 55; and / or (b) CDRH2 comprises or consists of the amino acid sequence set forth in SEQ ID NO.: 4, SEQ ID NO.: 57, or SEQ ID NO.: 61; and / or (c) CDRH3 comprises or consists of the amino acid sequence set forth in SEQ ID NO.: 5, SEQ ID NO.: 15, SEQ ID NO.: 51, or SEQ ID NO.: 53, and (d) CDRL1 comprises or consists of the amino acid sequence set forth in SEQ ID NO.: 9 or SEQ ID NO. NO.: 32 or consists of the amino acid sequence set forth in SEQ ID NO.: 32; and / or (e) CDRL2 comprises or consists of the amino acid sequence set forth in SEQ ID NO.: 10; and / or (f) CDRL3 comprises or consists of the amino acid sequence set forth in SEQ ID NO.: 11, 18, 21, 24, 33 or 67, optionally with the proviso that CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 do not comprise or consist of the amino acid sequence set forth in the following SEQ ID NOs.: (i) 3-5 and 9-11, respectively; (ii) 3, 4, 15 and 9-11, respectively; (iii) 3-5, 9, 10 and 18, respectively; (iv) 3-5, 9, 10 and 21, respectively; (v) 3-5, 9-11 and 24, respectively; or (vi) 3-5, 32, 96 and 33, respectively.

[0385] In certain embodiments, CDRH3 and CDRL3 comprise or consist of the amino acid sequences listed below: (i) 5 and 11, respectively; (ii) 5 and 18, respectively; (iii) 5 and 21, respectively; (iv) 5 and 24, respectively; (v) 5 and 33, respectively; (vi) 5 and 67, respectively; (vii) 15 and 11, respectively; (viii) 15 and 18, respectively; (ix) 15 and 21, respectively; (x) 15 and 24, respectively; (xi) 15 and 33, respectively; (xii) 5 and 67, respectively. or (xxiv) 53 and 67, respectively.

[0386] In certain additional embodiments, CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 comprise or consist of the amino acid sequences set forth in the following SEQ ID NOs.: (i) 3-5, 9, 10, and 67, respectively; (ii) 47, 4, 5, and 9-11, respectively; (iii) 47, 4, 5, 9, 10, and 67, respectively; (iv) 49, 4, 5, and 9-11, respectively; (v) 47, 4, 5, 9, 10, and 67, respectively; (vi) 55, 4, 5, and 9-11, respectively; (vii) 55, 4, 5, 9, 10 and 67, respectively; (viii) 3, 4, 51 and 9-11, respectively; (ix) 3, 4, 51, 9, 10 and 67, respectively; (x) 55, 4, 5 and 9-11, respectively; (xi) 55, 4, 5, 9, 10 and 67, respectively; (xii) 3, 61, 5 and 9-11, respectively; (xiii) 3, 61, 5, 9, 10 and 67, respectively; or (xiv) 3-5 and 9-11, respectively.

[0387] In some embodiments, an anti-influenza neuraminidase (anti-NA) antibody or an antigen-binding fragment thereof is provided, which comprises (i) a heavy chain variable domain (VH) and (ii) a light chain variable domain (VL), wherein: (i) VH comprises the complementarity determining regions (CDRs) H1, CDRH2, and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 2, and VL comprises CDRL1, CDRL2, and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 66; (ii) VH comprises CDRH1, CDRH2, and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 46, and VL comprises CDRL1, CDRL2, and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 8; (iii) VH comprises CDRH1, CDRH2, and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 46, and VL comprises CDRL1, CDRL2, and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO. NO.:17; (iv) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:46, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:20; (v) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:46, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:23; (vi) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:46, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:31; (vii) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:46, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:31 NO.:46, and the VL comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:66, and the VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:66; (viii) the VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:48, and the VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:8; (ix) the VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:48, and the VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:17; (x) the VH comprises SEQ ID NO.:48, and the VL comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:20, and the VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:23; (xii) the VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:48, and the VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:31; (xiii) the VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:48, and the VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:32. NO.: 66; (xiv) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 54, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 8; (xv) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 54, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 17; (xvi) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 54, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 20; (xvii) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 54, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 20; NO.:54, and VL comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:23, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:23; (xviii) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:54, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:31; (xix) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:54, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:66; (xx) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:56, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:8; (xxi) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:56, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:17; (xxii) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:56, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:20; (xxiii) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:56, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:20 NO.: 56, and the VL comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 23, and the VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 23; (xxiv) the VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 54, and the VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 31; (xxv) the VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 54, and the VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 66; (xxvi) the VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 60, and the VL comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 61. NO.: 8 of the VL amino acid sequence set forth in; (xxvii) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 60, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 17; (xxviii) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 60, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 20; (xxix) VH comprises SEQ ID NO.: 60, and the VL comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 23, and the VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 24; (xxx) the VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 60, and the VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 31; (xxxi) the VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 60, and the VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 66; (xxxii) the VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 50, and the VL comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 51. NO.: 8; (xxxiii) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 50, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 17; (xxxiv) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 50, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 20; (xxxv) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 50, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 23; (xxxvi) VH comprises SEQ ID NO.: 50, and the VL comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 31, and the VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 66; (xxxviii) the VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 52, and the VL comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 53.:8; (xxxix) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:52, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:17; (xxxx) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:52, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:20; (xxxxi) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:52, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:23; (xxxxii) VH comprises CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:52, and VL comprises CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:23; NO.:52, and the VL comprises CDRH1, CDRH2, and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:31, and the VL comprises CDRL1, CDRL2, and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:31; (xxxxiii) the VH comprises CDRH1, CDRH2, and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:52, and the VL comprises CDRL1, CDRL2, and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:66; or (xxxxiv) the VH comprises CDRH1, CDRH2, and CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:2, and the VL comprises CDRL1, CDRL2, and CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:8, wherein CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 are optionally defined according to the IMGT numbering system.

[0388] In certain embodiments, (i) VH comprises or consists of an amino acid sequence that is at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical (or similar) to the amino acid sequence set forth in any one of SEQ ID NOs.: 2, 14, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63, and 65; and (ii) VL comprises or consists of an amino acid sequence that is at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical (or similar) to the amino acid sequence set forth in any one of SEQ ID NOs.: 2, 14, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63, and 65. or consisting of an amino acid sequence having at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity (or similarity) to any one of SEQ ID NOs.: 8, 17, 20, 23, 31, 37, 66 and 68, or comprising or consisting of an amino acid sequence as set forth in any one of SEQ ID NOs.: 8, 17, 20, 23, 31, 37, 66 and 68, optionally with the proviso that VH and VL do not comprise or consist of the amino acid sequences as set forth as follows: (a) 2 and 8, respectively; (b) 14 and 8, respectively; (c) 2 and 17, respectively; (d) 2 and 20, respectively; (e) 2 and 23, respectively; or (f) 2 and 31, respectively. In some embodiments, (i) VH comprises, or consists of, an amino acid sequence that is at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical (or similar) to the amino acid sequence set forth in SEQ ID NO.:54, or comprises, or consists of, the amino acid sequence set forth in SEQ ID NO.:54, and (ii) VL comprises, or consists of, an amino acid sequence that is at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical (or similar) to the amino acid sequence set forth in SEQ ID NO.:8, or comprises, or consists of, the amino acid sequence set forth in SEQ ID NO.:9. NO.:8 or consisting of the amino acid sequence listed therein.

[0389] In some embodiments, VH and VL have at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity (or similarity) to the amino acid sequence set forth in SEQ ID NO: The amino acid sequence listed in NO or consisting of: (i) 2 and 66, respectively; (ii) 46 and 8, respectively; (iii) 46 and 17, respectively; (iv) 46 and 20, respectively; (v) 46 and 23, respectively; (vi) 46 and 31, respectively; (vii) 46 and 66, respectively; (viii) 48 and 8, respectively; (ix) 48 and 17, respectively; (x) 48 and 20, respectively; (xi) 48 and 23, respectively; (xii) 48 and 31, respectively; (xiii) 48 and 66, respectively; (xiv) 54 and 8, respectively; (xv) are 54 and 17 respectively; (xvi) are 54 and 20 respectively; (xvii) are 54 and 23 respectively; (xviii) are 54 and 31 respectively; (xix) are 54 and 66 respectively; (xx) are 56 and 8 respectively; (xxi) are 56 and 17 respectively; (xxii) are 56 and 20 respectively; (xxiii) are 56 and 23 respectively; (xxiv) are 54 and 31 respectively; (xxv) are 54 and 66 respectively; (xxvi) are 60 and 8 respectively; (xxvii) are 60 and 17 respectively; (xxviii) are 60 and 20 respectively; (xxix) are 60 respectively and 23; (xxx) 60 and 31 respectively; (xxxi) 60 and 66 respectively; (xxxii) 2, 14, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 37 respectively; (xxxiii) 2, 14, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 68 respectively; (xxxiv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 8 respectively; (xxxv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 8 respectively 4, 56, 58, 60, 63 or 65 and 17; (xxxvi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 20, respectively; (xxxvii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23, respectively; (xxxviii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 31, respectively; (xxxix) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 37, respectively;(xxxx) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 66, respectively; (xxxxi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 68, respectively; (xxxxii) 2, 14, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 66, respectively; (xxxxiii) 2 and 8, respectively; or (xxxxiv) 2 and 37, respectively.

[0390] The variable domains of antibodies and antigen-binding fragments may comprise framework region amino acid sequences. Framework region amino acid sequences can be identified using, for example, the IMGT, Kabat, Chothia, Enhanced Chothia, Contact, Martin, or AHo numbering systems or methods. In some embodiments, the VH comprises framework region (FR) 1, FR2, FR3, and / or FR4 of the currently disclosed VH amino acid sequences, or comprises a variant of the disclosed FR1, FR2, FR3, and / or FR4 amino acid sequences, wherein the variant comprises, consists essentially of, or consists of one, two, three, four, five, six, seven, eight, nine, or ten amino acid substitutions, insertions, and / or deletions compared to the disclosed VH amino acid sequences. In some embodiments, the variants of the disclosed FR1, FR2, FR3 and / or FR4 amino acid sequences have at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity (or similarity) to the disclosed FR1, FR2, FR3 and / or FR4 amino acid sequences, respectively. In some embodiments, the VL comprises a framework region (FR) 1, FR2, FR3 and / or FR4 of the presently disclosed VL amino acid sequence, or comprises a variant of the disclosed FR1, FR2, FR3 and / or FR4 amino acid sequence, wherein the variant comprises, consists essentially of, or consists of one, two, three, four, five, six, seven, eight, nine or ten amino acid substitutions, insertions and / or deletions compared to the disclosed VL amino acid sequence. In some embodiments, variants of the disclosed FR1, FR2, FR3 and / or FR4 amino acid sequences have at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity (or similarity) to the disclosed FR1, FR2, FR3 and / or FR4 amino acid sequences, respectively.

[0391] In some embodiments, the antibody or antigen-binding fragment comprises:

[0392] (1) VH, the VH comprising: (i) FR1, the FR1 comprising Figure 71 or a variant thereof comprising one, two, three, four, five, six, seven, eight, nine or ten amino acid substitutions, insertions and / or deletions, (ii) a FR2 comprising: Figure 71 or a variant thereof comprising one, two, three, four, five, six, seven, eight, nine or ten amino acid substitutions, insertions and / or deletions, (iii) a FR3 comprising: Figure 71 or (iv) a VH FR3 amino acid sequence of any one of "FNI9-VH-WT", "FNI9-VH-FR124GL", "FNI9-VH.4", "FNI9-VH.5", "FNI9-VH.6", "FNI9-VH.7", "FNI9-VH.8", "FNI9-VH.9", "FNI9-VH.10", "FNI9-VH.11", "FNI9-VH.12" and "FNI9-VH.13" as shown, or a variant thereof comprising one, two, three, four, five, six, seven, eight, nine or ten amino acid substitutions, insertions and / or deletions, and / or (iv) a FR4 comprising Figure 71The VH FR4 amino acid sequence of any one of "FNI9-VH-WT", "FNI9-VH-FR124GL", "FNI9-VH.4", "FNI9-VH.5", "FNI9-VH.6", "FNI9-VH.7", "FNI9-VH.8", "FNI9-VH.9", "FNI9-VH.10", "FNI9-VH.11", "FNI9-VH.12" and "FNI9-VH.13" as shown, or a variant thereof comprising one, two, three, four, five, six, seven, eight, nine or ten amino acid substitutions, insertions and / or deletions. And / or

[0393] (2) VL, which includes (i) FR1, which includes Figure 71 or a variant thereof comprising one, two, three, four, five, six, seven, eight, nine or ten amino acid substitutions, insertions and / or deletions, (ii) a FR2 comprising: Figure 71 or a variant thereof comprising one, two, three, four, five, six, seven, eight, nine or ten amino acid substitutions, insertions and / or deletions, (iii) a FR3 comprising: Figure 71 or a variant thereof comprising one, two, three, four, five, six, seven, eight, nine or ten amino acid substitutions, insertions and / or deletions, and / or (iv) a FR4 comprising: Figure 71In some embodiments, the VH FR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to IMGT. In some embodiments, the VH FR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to Kabat. In some embodiments, VHFR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to Chothia. In some embodiments, VH FR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to Enhance Chothia. In some embodiments, VH FR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to Contact. In some embodiments, VH FR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to Martin. In some embodiments, VH FR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to North. In some embodiments, VH FR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to AHo.

[0394] In some embodiments, the antibody or antigen-binding fragment comprises:

[0395] (1) VH, the VH comprising: (i) FR1, the FR1 comprising Figure 71or a sequence that is at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical (or similar) to the FR1 amino acid sequence of any one of "FNI9-VH-WT", "FNI9-VH-FR124GL", "FNI9-VH.4", "FNI9-VH.5", "FNI9-VH.6", "FNI9-VH.7", "FNI9-VH.8", "FNI9-VH.9", "FNI9-VH.10", "FNI9-VH.11", "FNI9-VH.12" and "FNI9-VH.13", (ii) a FR2 comprising an amino acid sequence that is at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical (or similar) to the FR1 amino acid sequence of any one of "FNI9-VH-WT", "FNI9-VH-FR124GL", "FNI9-VH.4", "FNI9-VH.5", "FNI9-VH.6", "FNI9-VH.7", "FNI9-VH.8", "FNI9-VH.9", "FNI9-VH.10", "FNI9-VH.11", "FNI9-VH.12" and "FNI9-VH.13", Figure 71 or a VH FR2 amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity (or similarity) to any one of "FNI9-VH-WT", "FNI9-VH-FR124GL", "FNI9-VH.4", "FNI9-VH.5", "FNI9-VH.6", "FNI9-VH.7", "FNI9-VH.8", "FNI9-VH.9", "FNI9-VH.10", "FNI9-VH.11", "FNI9-VH.12" and "FNI9-VH.13" as shown, (iii) an FR3 comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity (or similarity) to any one of "FNI9-VH-WT", "FNI9-VH-FR124GL", "FNI9-VH.4", "FNI9-VH.5", "FNI9-VH.6", "FNI9-VH.7", "FNI9-VH.8", "FNI9-VH.9", "FNI9-VH.10", "FNI9-VH.11", "FNI9-VH.12" and "FNI9-VH.13", Figure 71 or (iv) an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity (or similarity) to the VH FR3 amino acid sequence of any one of "FNI9-VH-WT", "FNI9-VH-FR124GL", "FNI9-VH.4", "FNI9-VH.5", "FNI9-VH.6", "FNI9-VH.7", "FNI9-VH.8", "FNI9-VH.9", "FNI9-VH.10", "FNI9-VH.11", "FNI9-VH.12" and "FNI9-VH.13", and / or (iv) an FR4 comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity (or similarity) to the VH FR3 amino acid sequence of any one of "FNI9-VH-WT", "FNI9-VH-FR124GL", "FNI9-VH.4", "FNI9-VH.5", "FNI9-VH.6", "FNI9-VH.7", "FNI9-VH.8", "FNI9-VH.9", "FNI9-VH.10", "FNI9-VH.11", "FNI9-VH.12" and "FNI9-VH.13", Figure 71or a VHFR4 amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity (or similarity) to any one of the VHFR4 amino acid sequences of "FNI9-VH-WT", "FNI9-VH-FR124GL", "FNI9-VH.4", "FNI9-VH.5", "FNI9-VH.6", "FNI9-VH.7", "FNI9-VH.8", "FNI9-VH.9", "FNI9-VH.10", "FNI9-VH.11", "FNI9-VH.12" and "FNI9-VH.13" as shown; and / or

[0396] (2) VL, the VL comprising: (i) FR1, the FR1 comprising Figure 71 or consisting essentially of, or consisting of, an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity (or similarity) to the VL FR1 amino acid sequence of any one of "FNI9-VK-WT", "FNI9-VK.7" and "FNI9-VK.8" as shown; and (ii) FR2 comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity (or similarity) to the VL FR1 amino acid sequence of any one of "FNI9-VK-WT", "FNI9-VK.7" and "FNI9-VK.8", Figure 71 an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity (or similarity) to the VL FR2 amino acid sequence of any one of "FNI9-VK-WT", "FNI9-VK.7" and "FNI9-VK.8" as shown, (iii) an FR3 comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity (or similarity) to the VL FR2 amino acid sequence of any one of "FNI9-VK-WT", "FNI9-VK.7" and "FNI9-VK.8", Figure 71 The VL FR3 amino acid sequence of any one of "FNI9-VK-WT", "FNI9-VK.7" and "FNI9-VK.8" as shown in the present invention has at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity (or similarity), and / or (iv) FR4 comprising an amino acid sequence having ... Figure 71The VL FR4 amino acid sequence of any one of "FNI9-VK-WT", "FNI9-VK.7", and "FNI9-VK.8" as shown has, consists essentially of, or consists of an amino acid sequence that is at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical (or similar). In some embodiments, VH FR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to IMGT. In some embodiments, VH FR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to Kabat. In some embodiments, VH FR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to Chothia. In some embodiments, VH FR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to Enhance Chothia. In some embodiments, VH FR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to Contact. In some embodiments, VH FR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to Martin. In some embodiments, VHFR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to North. In some embodiments, VH FR1, VH FR2, VH FR3, VH FR4, VL FR1, VL FR2, VL FR3, and VL FR4 are according to AHo.

[0397] In some embodiments, VH and VL comprise or consist of the amino acid sequences set forth in SEQ ID NO.: (i) 45 and 37, respectively; (ii) 46 and 37, respectively; (iii) 48 and 37, respectively; (iv) 50 and 37, respectively; (v) 52 and 37, respectively; (vi) 54 and 37, respectively; (vii) 56 and 37, respectively; (viii) 58 and 37, respectively; (ix) 60 and 37, respectively; (x) 63 and 37, respectively; (xi) 65 and 37, respectively; (xii) 45 and 66, respectively; (xiii) 46 and 66, respectively; (xiv) 48 and 66, respectively; (xv) 50 and 66, respectively; (xvi) 52 and 66, respectively; (xvii) ) are 54 and 66 respectively; (xviii) are 56 and 66 respectively; (xix) are 58 and 66 respectively; (xx) are 60 and 66 respectively; (xxi) are 63 and 66 respectively; (xxii) are 65 and 66 respectively; (xxiii) are 45 and 68 respectively; (xxiv) are 46 and 68 respectively; (xxv) are 48 and 68 respectively; (xxvi) are 50 and 68 respectively; (xxvii) are 52 and 68 respectively; (xxviii) are 54 and 68 respectively; (xxix) are 56 and 68 respectively; (xxx) are 58 and 68 respectively; (xxxi) are 60 and 68 respectively; (xxxii) are 63 and 68 respectively; (x xxiii) 65 and 68 respectively; (xxxiv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 8 respectively; (xxxv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 17 respectively; (xxxvi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 20 respectively; (xxxvii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23 respectively; (xxxviii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23 respectively; or (xxxxi) 2, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 66, respectively; (xxxxii) 2, 14, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 66, respectively; (xxxxiii) 2 and 8, respectively; or (xxxxiv) 2 and 37, respectively.

[0398] In certain embodiments, VH and VL comprise or consist of the amino acid sequences set forth in SEQ ID NO.: 54 and 8, respectively.

[0399] In certain embodiments, an antibody comprising a heavy chain and a light chain is provided, wherein the heavy chain and the light chain comprise the amino acid sequences set forth in the following SEQ ID NOs.: (i) 45 and 37, respectively; (ii) 46 and 37, respectively; (iii) 48 and 37, respectively; (iv) 50 and 37, respectively; (v) 52 and 37, respectively; (vi) 54 and 37, respectively; (vii) 56 and 37, respectively; (viii) 58 and 37, respectively; (ix) 60 and 37, respectively; (x) 63 and 37, respectively; (xi) 65 and 37, respectively; (xii) 45 and 66, respectively; (xiii) 46 and 66, respectively; (xiv) 48 and 66, respectively; (xv) 50 and 66, respectively; (xvi) 52 and 66, respectively; (xvii) are 54 and 66 respectively; (xviii) are 56 and 66 respectively; (xix) are 58 and 66 respectively; (xx) are 60 and 66 respectively; (xxi) are 63 and 66 respectively; (xxii) are 65 and 66 respectively; (xxiii) are 45 and 68 respectively; (xxiv) are 46 and 68 respectively; (xxv) are 48 and 68 respectively; (xxvi) are 50 and 68 respectively; (xxvii) are 52 and 68 respectively; (xxviii) are 54 and 68 respectively; (xxix) are 56 and 68 respectively; (xxx) are 58 and 68 respectively; (xxxi) are 60 and 68 respectively; (xxxii) are 63 and 68 respectively; (xxx iii) 65 and 68 respectively; (xxxiv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 8 respectively; (xxxv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 17 respectively; (xxxvi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 20 respectively; (xxxvii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23 respectively; (xxxviii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23 respectively or (xxxxi) 2, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 66, respectively; (xxxxii) 2, 14, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 66, respectively; (xxxxiii) 2 and 8, respectively; or (xxxxiv) 2 and 37, respectively.

[0400] In certain embodiments, the heavy and light chains comprise the amino acid sequences set forth in SEQ ID NOs.: 54 and 8, respectively.

[0401] In some embodiments, an anti-influenza neuraminidase (anti-NA) antibody or antigen-binding fragment thereof is provided, comprising: (i) a heavy chain variable domain (VH) comprising complementarity determining regions (CDRs) H1, CDRH2, and CDRH3, and (ii) a light chain variable domain (VL) comprising CDRL1, CDRL2, and CDRL3, wherein:

[0402] (a) CDRH2 is set forth in SEQ ID NO.:4 and contained in SEQ ID NO.:59, CDRH1 is set forth in SEQ ID NO.:3, and CDRH3 is set forth in SEQ ID NO.:5;

[0403] (b) CDRH2 is as set forth in SEQ ID NO.: 61 and contained in SEQ ID NO.: 62, CDRH1 is as set forth in SEQ ID NO.: 3, and CDRH3 is as set forth in SEQ ID NO.: 5; or (c) CDRH2 is as set forth in SEQ ID NO.: 61 and contained in SEQ ID NO.: 64, CDRH1 is as set forth in SEQ ID NO.: 3,

[0404] And CDRH3 is set forth in SEQ ID NO.:5.

[0405] In additional embodiments, CDRL1 is as set forth in SEQ ID NO.: 9, CDRL2 is as set forth in SEQ ID NO.: 10, and CDRL3 is as set forth in any one of SEQ ID NOs.: 11, 18, 21, 24, 33, and 67. In other embodiments, CDRL1 is as set forth in SEQ ID NO.: 32, CDRL2 is as set forth in SEQ ID NO.: 10, and CDRL3 is as set forth in any one of SEQ ID NOs.: 11, 18, 21, 24, 33, and 67. In other embodiments, CDRL1 is as set forth in SEQ ID NO.: 32, CDRL2 is as set forth in SEQ ID NO.: 96, and CDRL3 is as set forth in SEQ ID NO.: 33.

[0406] In some embodiments, an anti-influenza neuraminidase (anti-NA) antibody or antigen-binding fragment thereof is provided, comprising a heavy chain variable domain (VH) and a light chain variable domain (VL), wherein VH and VL comprise the following SEQ ID or consisting of the amino acid sequence set forth in NO.: (i) 65 and 68, respectively; (ii) 46 and 8, respectively; (iii) 48 and 8, respectively; (iv) 50 and 8, respectively; (v) 52 and 8, respectively; (vi) 54 and 8, respectively; (vii) 56 and 8, respectively; (viii) 58 and 8, respectively; (ix) 60 and 8, respectively; (x) 63 and 8, respectively; (xi) 46 and 66, respectively; (xii) 48 and 66, respectively; (xiii) 50 and 66, respectively; (xiv) 52 and 66, respectively; (xv) 54 and 66, respectively; (xvi) 56 and 66, respectively; (xvii) 58 and 66, respectively; (xviii) 60 and 66, respectively; (xix) 63 and 66, respectively; or (xx) 2 and 37, respectively.

[0407] In some embodiments, the influenza comprises influenza A virus, influenza B virus, or both.

[0408] In some embodiments, the antibody or antigen-binding fragment comprises a human antibody, a monoclonal antibody, a purified antibody, a single-chain antibody, Fab, Fab', F(ab')2, or Fv.

[0409] In some embodiments, the antibody or antigen-binding fragment is a multispecific antibody or antigen-binding fragment, wherein optionally the antibody or antigen-binding fragment is a bispecific antibody or antigen-binding fragment.

[0410] In some embodiments, the antibody or antigen-binding fragment includes (e.g., IgG1) Fc polypeptide or fragment thereof. In some embodiments, the antibody or antigen-binding fragment includes IgG, IgA, IgM, IgE or IgD isotype. In other embodiments, the antibody or antigen-binding fragment includes an IgG isotype selected from IgG1, IgG2, IgG3 and IgG4. In certain embodiments, the antibody or antigen-binding fragment includes an IgG1 isotype. In some embodiments, the antibody or antigen-binding fragment includes an IgG1m3 allotype, an IgG1m17 allotype, an IgG1m1 allotype or any combination thereof.

[0411] In some embodiments, the Fc polypeptide or fragment thereof comprises: (i) a mutation that increases binding affinity for human FcRn compared to a reference Fc polypeptide that does not comprise the mutation (e.g., as measured using surface plasmon resonance (SPR) (e.g., a Biacore, e.g., a T200 instrument, using the manufacturer's protocol)); and / or (ii) a mutation that increases binding affinity for human FcγR compared to a reference Fc polypeptide that does not comprise the mutation (e.g., as measured using surface plasmon resonance (SPR) (e.g., a Biacore, e.g., a T200 instrument, using the manufacturer's protocol, and / or as measured using mesoscale discovery (MSD))).

[0412] In some embodiments, mutations that increase binding affinity to human FcRn include: M428L; N434S; N434H; N434A; N434S; M252Y; S254T; T256E; T250Q; P257I; Q311I; D376V; T307A; E380A; or any combination thereof. In some embodiments, the mutations that increase binding affinity to human FcRn include: (i) M428L / N434S; (ii) M252Y / S254T / T256E; (iii) T250Q / M428L; (iv) P257I / Q311I; (v) P257I / N434H; (vi) D376V / N434H; (vii) T307A / E380A / N434A; (viii) M428L / N434A; or any combination of (ix) (i)-(viii). In some embodiments, the mutations that increase binding affinity to human FcRn include M428L / N434S or M428L / N434A.

[0413] In some embodiments, mutations that enhance binding to FcγRs include S239D; I332E; A330L; G236A; or any combination thereof. In some embodiments, mutations that enhance binding to FcγRs include: (i) S239D / I332E; (ii) S239D / A330L / I332E; (iii) G236A / S239D / I332E; or (iv) G236A / A330L / I332E, wherein the Fc polypeptide or fragment thereof optionally comprises Ser at position 239.

[0414] In some embodiments, the antibody or antigen-binding fragment comprises a mutation that alters glycosylation, wherein the mutation that alters glycosylation comprises N297A, N297Q, or N297G, and / or is aglycosylated, and / or is afucosylated.

[0415] In some embodiments, an anti-influenza neuraminidase (anti-NA) antibody or antigen-binding fragment thereof is provided, comprising: (i) in the heavy chain, (i)(a) a variable domain (VH) comprising the complementarity determining regions (CDRs) H1, CDRH2, and CDRH3 amino acid sequences set forth in SEQ ID NOs.: 3-5, respectively, and (i)(b) mutations M428L and N434A; and (ii) in the light chain, a light chain variable domain (VL) comprising the CDRL1, CDRL2, and CDRL3 amino acid sequences set forth in SEQ ID NOs.: 9-11, respectively.

[0416] In some embodiments, an anti-influenza neuraminidase (anti-NA) antibody or antigen-binding fragment thereof is provided, comprising: (i) in the heavy chain, (i)(a) a variable domain (VH) comprising the complementarity determining regions (CDRs) H1, CDRH2, and CDRH3 amino acid sequences set forth in SEQ ID NOs.: 3-5, respectively, and (i)(b) mutations M428L and N434S; and (ii) in the light chain, a light chain variable domain (VL) comprising the CDRL1, CDRL2, and CDRL3 amino acid sequences set forth in SEQ ID NOs.: 9-11, respectively.

[0417] In certain embodiments, VH and VL have at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least ...

Claims

1. An anti-influenza neuraminidase (anti-NA) antibody or an antigen-binding fragment thereof, the anti-influenza neuraminidase (anti-NA) antibody or an antigen-binding fragment thereof comprising: (i) a heavy chain variable domain (VH) comprising complementarity determining regions (CDRs) H1, CDRH2 and CDRH3, and (ii) a light chain variable domain (VL) comprising CDRL1, CDRL2 and CDRL3, wherein: (a) the CDRH1 comprises or consists of the amino acid sequence set forth in SEQ ID NO.:55, SEQ ID NO.:3, SEQ ID NO.:47 or SEQ ID NO.:49; and / or (b) the CDRH2 comprises or consists of the amino acid sequence set forth in SEQ ID NO.:4, SEQ ID NO.:57 or SEQ ID NO.:61; and / or (c) the CDRH3 comprises or consists of the amino acid sequence set forth in SEQ ID NO.:5, SEQ ID NO.:15, SEQ ID NO.:51 or SEQ ID NO.:53, (d) the CDRL1 comprises or consists of the amino acid sequence set forth in SEQ ID NO.: 9 or SEQ ID NO.: 32; and / or (e) the CDRL2 comprises or consists of the amino acid sequence listed in SEQ ID NO.: 10; and / or (f) the CDRL3 comprises or consists of the amino acid sequence set forth in SEQ ID NO.: 11, 18, 21, 24, 33 or 67, Optionally, the proviso is that the CDRH1, the CDRH2, the CDRH3, the CDRL1, the CDRL2 and the CDRL3 do not comprise or consist of the amino acid sequences listed in the following SEQ ID NOs: (i) 3-5 and 9-11, respectively; (ii) 3, 4, 15 and 9-11, respectively; (iii) 3-5, 9, 10 and 18, respectively; (iv) 3-5, 9, 10 and 21, respectively; (v) 3-5, 9-10 and 24, respectively; or (vi) 3-5, 32, 96 and 33, respectively.

2. The antibody or antigen-binding fragment according to claim 1, wherein the CDRH3 and the CDRL3 comprise or consist of the amino acid sequence set forth in SEQ ID NO.: (i) are 5 and 11 respectively; (ii) are 5 and 18 respectively; (iii) are 5 and 21 respectively; (iv) are 5 and 24 respectively; (v) are 5 and 33 respectively; (vi) are 5 and 67 respectively; (vii) are 15 and 11 respectively; (viii) are 15 and 18 respectively; (ix) are 15 and 21 respectively; (x) are 15 and 24 respectively; (xi) are 15 and 33 respectively; (xii) are 15 and 67 respectively; (xiii) are 51 respectively and 11, respectively; (xiv) 51 and 18, respectively; (xv) 51 and 21, respectively; (xvi) 51 and 24, respectively; (xvii) 51 and 33, respectively; (xviii) 51 and 67, respectively; (xix) 53 and 11, respectively; (xx) 53 and 18, respectively; (xxi) 53 and 21, respectively; (xxii) 53 and 24, respectively; (xxiii) 53 and 33, respectively; or (xxiv) 53 and 67, respectively.

3. The antibody or antigen-binding fragment according to claim 1 or 2, wherein the CDRH1, the CDRH2, the CDRH3, the CDRL1, the CDRL2 and the CDRL3 comprise or consist of the amino acid sequence listed in the following SEQ ID NO.: (i) 55, 4, 5 and 9-11, respectively; (ii) 47, 4, 5 and 9-11, respectively; (iii) 47, 4, 5, 9, 10 and 67, respectively; (iv) 49, 4, 5 and 9-11, respectively; (v) 47, 4, 5, 9, 10 and 67, respectively; (vi) 3-5, 9, 10 and 67, respectively; (vii) 55, 4, 5, 9, 10 and 67, respectively; (viii) 3, 4, 51 and 9-11, respectively; (ix) 3, 4, 51, 9, 10 and 67, respectively; (x) 55, 4, 5 and 9-11, respectively; (xi) 55, 4, 5, 9, 10 and 67, respectively; (xii) 3, 61, 5 and 9-11, respectively; (xiii) 3, 61, 5, 9, 10 and 67, respectively; (xiv) 3-5 and 9-11, respectively; or (xv) are 3, 57, 5 and 9-10 respectively.

4. An anti-influenza neuraminidase (anti-NA) antibody or an antigen-binding fragment thereof, wherein the anti-influenza neuraminidase (anti-NA) antibody or an antigen-binding fragment thereof comprises (i) a heavy chain variable domain (VH) and (ii) a light chain variable domain (VL), wherein: (i) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:54, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:8; (ii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:46, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:8; (iii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:46, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:17; (iv) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:46, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:20; (v) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:46, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:23; (vi) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:46, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:31; (vii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:46, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:66; (viii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:48, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:8; (ix) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:48, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:17; (x) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:48, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:20; (xi) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:48, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:23; (xii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:48, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:31; (xiii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:48, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:66; (xiv) the VH comprises the complementarity determining region (CDR) H1, the CDRH2 and the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:2, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:66; (xv) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:54, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:17; (xvi) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:54, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:20; (xvii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:54, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:23; (xviii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:54, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:31; (xix) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:54, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:66; (xx) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:56, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:8; (xxi) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:56, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:17; (xxii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:56, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:20; (xxiii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:56, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:23; (xxiv) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:54, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:31; (xxv) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:54, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:66; (xxvi) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:60, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:8; (xxvii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:60, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:17; (xxviii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:60, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:20; (xxix) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:60, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:23; (xxx) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:60, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:31; (xxxi) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:60, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:66; (xxxii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:50, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:8; (xxxiii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:50, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:17; (xxxiv) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:50, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:20; (xxxv) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:50, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:23; (xxxvi) the VH comprises the CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:50, and the VL comprises the CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:31; (xxxvii) the VH comprises the CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:50, and the VL comprises the CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:66; (xxxviii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:52, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:8; (xxxix) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:52, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:17; (xxxx) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:52, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:20; (xxxxi) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:52, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:23; (xxxxii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:52, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:31; (xxxxiii) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:52, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:66; (xxxxiv) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:2, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:8, or (xxxxv) the VH comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:65, and the VL comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:68, wherein CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 are optionally defined according to the IMGT numbering system.

5. The antibody or antigen-binding fragment according to any one of claims 1 to 4, wherein: (i) the VH comprises the same sequence as SEQ ID NO.: 54, 2, 14, 45, 46, 48, 50, 52, 56, 58, 60, 63 and 65 has at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity to any one of the amino acid sequences listed in SEQ ID NO.: 54, 2, 14, 45, 46, 48, 50, 52, 56, 58, 60, 63 and 65, or consists of an amino acid sequence having ... (ii) the VL comprises or consists of an amino acid sequence that is at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical to the amino acid sequence set forth in any one of SEQ ID NOs.: 8, 17, 20, 23, 31, 37, 66 and 68, or comprising or consisting of the amino acid sequence listed in any one of SEQ ID NO.: 8, 17, 20, 23, 31, 37, 66 and 68, Optionally, the proviso is that said VH and said VL do not comprise or consist of the amino acid sequences listed below: (a) 2 and 8, respectively; (b) 14 and 8, respectively; (c) 2 and 17, respectively; (d) 2 and 20, respectively; (e) 2 and 23, respectively; or (f) 2 and 31, respectively.

6. The antibody or antigen-binding fragment of any one of claims 1 to 5, wherein the VH and the VL have at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity with the amino acid sequence listed in SEQ ID NO: (i) 54 and 8 respectively; (ii) 46 and 8 respectively; (iii) 46 and 17 respectively; (iv) 46 and 20 respectively; (v) 46 and 23 respectively; (vi) 46 and 31 respectively; (vii) 46 and 66 respectively; (viii) 48 and 8 respectively; (ix) 48 and 17 respectively; (x) 48 and 20 respectively; (xi) 48 and 23 respectively; (xii) 48 and 31 respectively; (xiii) 48 and 66 respectively ; (xiv) are 2 and 66 respectively; (xv) are 54 and 17 respectively; (xvi) are 54 and 20 respectively; (xvii) are 54 and 23 respectively; (xviii) are 54 and 31 respectively; (xix) are 54 and 66 respectively; (xx) are 56 and 8 respectively; (xxi) are 56 and 17 respectively; (xxii) are 56 and 20 respectively; (xxiii) are 56 and 23 respectively; (xxiv) are 54 and 31 respectively; (xxv) are 54 and 66 respectively; (xxvi) are 60 and 8, respectively; (xxvii) are 60 and 17, respectively; (xxviii) are 60 and 20, respectively; (xxix) are 60 and 23, respectively; (xxx) are 60 and 31, respectively; (xxxi) are 60 and 66, respectively; (xxxii) are 2, 14, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 37, respectively; (xxxiii) are 2, 14, 45, 46, 4 8, 50, 52, 54, 56, 58, 60, 63 or 65 and 68; (xxxiv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 8, respectively; (xxxv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 17, respectively; (xxxvi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 20, respectively; xxxvii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23, respectively; (xxxviii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 31, respectively; (xxxix) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 37, respectively; (xxxx) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 37, respectively. , 56, 58, 60, 63 or 65 and 66 respectively; (xxxxi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 68 respectively; (xxxxii) 2, 14, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 66 respectively; (xxxxiii) 2 and 8 respectively; (xxxxiv) 2 and 37 respectively; or (xxxxv) 65 and 68 respectively.

7. The antibody or antigen-binding fragment according to any one of claims 1 to 6, wherein the VH and the VL comprise or consist of the amino acid sequence listed in the following SEQ ID NO.: (i) are 54 and 8 respectively; (ii) are 46 and 37 respectively; (iii) are 48 and 37 respectively; (iv) are 50 and 37 respectively; (v) are 52 and 37 respectively; (vi) are 54 and 37 respectively; (vii) are 56 and 37 respectively; (viii) are 58 and 37 respectively; (ix) are 60 and 37 respectively; (x) are 63 and 37 respectively; (xi) are 65 and 37 respectively; (xii) are 45 and 66 respectively; (xiii) are 46 and 66 respectively; (xiv) are 48 and 66 respectively; (xv) 50 and 66 respectively; (xvi) 52 and 66 respectively; (xvii) 54 and 66 respectively; (xviii) 56 and 66 respectively; (xix) 58 and 66 respectively; (xx) 60 and 66 respectively; (xxi) 63 and 66 respectively; (xxii) 65 and 66 respectively; (xxiii) 45 and 68 respectively; (xxiv) 46 and 68 respectively; (xxv) 48 and 68 respectively; (xxvi) 50 and 68 respectively; (xxvii) 52 and 68, respectively; (xxviii) 54 and 68, respectively; (xxix) 56 and 68, respectively; (xxx) 58 and 68, respectively; (xxxi) 60 and 68, respectively; (xxxii) 63 and 68, respectively; (xxxiii) 65 and 68, respectively; (xxxiv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 8, respectively ; (xxxv) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 17, respectively; (xxxvi) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 20, respectively; (xxxvii) 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 23, respectively; (xxxviii) 45, 4 6, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 31; (xxxix) 2, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 37 respectively; (xxxx) 2, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 or 65 and 66 respectively; (xxxxi) 2, 45, 46, 48, 50, 52, or (xxxxvii) 56 and 8 respectively.

8. The antibody or antigen-binding fragment according to any one of claims 1 to 7, wherein the VH and the VL comprise or consist of the amino acid sequences listed in SEQ ID NO.: 54 and 8, respectively.

9. An anti-influenza neuraminidase (anti-NA) antibody or an antigen-binding fragment thereof, the anti-influenza neuraminidase (anti-NA) antibody or an antigen-binding fragment thereof comprising: (i) a heavy chain variable domain (VH) comprising complementarity determining regions (CDRs) H1, CDRH2 and CDRH3, and (ii) a light chain variable domain (VL) comprising CDRL1, CDRL2 and CDRL3, wherein: (a) CDRH2 is as set forth in SEQ ID NO.:4 and contained in SEQ ID NO.:59, CDRH1 is as set forth in SEQ ID NO.:3, and CDRH3 is as set forth in SEQ ID NO.:5; (b) CDRH2 is as set forth in SEQ ID NO.:61 and contained in SEQ ID NO.:62, CDRH1 is as set forth in SEQ ID NO.:3, and CDRH3 is as set forth in SEQ ID NO.:5; or (c) CDRH2 is as set forth in SEQ ID NO.:61 and contained in SEQ ID NO.:64, CDRH1 is as set forth in SEQ ID NO.:3, and CDRH3 is as set forth in SEQ ID NO.:

5.

10. The antibody or antigen-binding fragment of claim 9, wherein CDRL1 is as set forth in SEQ ID NO.: 9, CDRL2 is as set forth in SEQ ID NO.: 10, and CDRL3 is as set forth in any one of SEQ ID NOs.: 11, 18, 21, 24, 33 and 67.

11. The antibody or antigen-binding fragment of claim 10, wherein CDRL1 is as set forth in SEQ ID NO.: 32, CDRL2 is as set forth in SEQ ID NO.: 10 or 96, and CDRL3 is as set forth in any one of SEQ ID NO.: 11, 18, 21, 24, 33 and 67.

12. An anti-influenza neuraminidase (anti-NA) antibody or an antigen-binding fragment thereof, wherein the anti-influenza neuraminidase (anti-NA) antibody or an antigen-binding fragment thereof comprises a heavy chain variable domain (VH) and a light chain variable domain (VL), wherein the VH and the VL comprise or consist of the amino acid sequence listed in the following SEQ ID NO.: (i) 54 and 8, respectively; (ii) 46 and 8, respectively; (iii) 48 and 8, respectively; (iv) 50 and 8, respectively; (v) 52 and 8, respectively; (vi) 65 and 68, respectively; (vii) 56 and 8, respectively; (viii) 58 and 8, respectively; (ix) 60 and 8, respectively; (x) 63 and 8, respectively; (xi) 46 and 66, respectively; (xii) 48 and 66, respectively; (xiii) 50 and 66, respectively; (xiv) 52 and 66, respectively; (xv) 54 and 66, respectively; (xvi) 56 and 66, respectively; (xvii) 58 and 66, respectively; (xviii) 60 and 66, respectively; (xix) 63 and 66, respectively; or (xx) 2 and 37, respectively.

13. The antibody or antigen-binding fragment of any one of claims 1 to 12, wherein the influenza comprises influenza A virus, influenza B virus, or both.

14. The antibody or antigen-binding fragment of any one of claims 1 to 13, wherein the antibody or the antigen-binding fragment comprises a human antibody, a monoclonal antibody, a purified antibody, a single-chain antibody, Fab, Fab', F(ab')2 or Fv.

15. The antibody or antigen binding fragment according to any one of claims 1 to 14, wherein the antibody or antigen binding fragment is a multispecific antibody or antigen binding fragment, wherein optionally, the antibody or antigen binding fragment is a bispecific antibody or antigen binding fragment.

16. The antibody or antigen-binding fragment of any one of claims 1 to 15, wherein the antibody or antigen-binding fragment comprises a (eg, IgG1) Fc polypeptide or fragment thereof.

17. The antibody or antigen-binding fragment of any one of claims 1 to 16, comprising an IgG, IgA, IgM, IgE or IgD isotype.

18. The antibody or antigen-binding fragment of any one of claims 1 to 17, comprising an IgG isotype selected from IgG1, IgG2, IgG3 and IgG4, optionally with C-terminal lysine removed or with C-terminal glycine-lysine removed.

19. The antibody or antigen-binding fragment of any one of claims 1 to 18, comprising an IgG1 isotype.

20. The antibody or antigen-binding fragment of any one of claims 1 to 19, comprising an IgG1m3 allotype, an IgG1m17 allotype, an IgG1m1 allotype, or any combination thereof.

21. The antibody or antigen-binding fragment of claims 16 to 20, wherein the Fc polypeptide or fragment thereof comprises: (i) said mutation that increases binding affinity to human FcRn compared to a reference Fc polypeptide not comprising the mutation (e.g., as measured using surface plasmon resonance (SPR) (e.g., Biacore, e.g., T200 instrument, using the manufacturer's protocol)); and / or (ii) said mutation that increases binding affinity to a human FcγR compared to a reference Fc polypeptide not comprising the mutation (e.g., as measured using surface plasmon resonance (SPR) (e.g., a Biacore, e.g., T200 instrument, using the manufacturer's protocol, and / or as measured using mesoscale discovery (MSD))).

22. The antibody or antigen-binding fragment of claim 21, wherein the mutations that increase binding affinity to human FcRn comprise: M428L; N434S; N434H; N434A; N434S; M252Y; S254T; T256E; T250Q; P257I; Q311I; D376V; T307A; E380A; or any combination thereof.

23. The antibody or antigen-binding fragment of claim 21 or 22, wherein the mutations that increase binding affinity to human FcRn comprise: (i) M428L / N434S; (ii) M252Y / S254T / T256E; (iii) T250Q / M428L; (iv) P257I / Q311I; (v) P257I / N434H; (vi) D376V / N434H; (vii) T307A / E380A / N434A; (viii) M428L / N434A; or any combination of (ix)(i)-(viii).

24. The antibody or antigen-binding fragment of any one of claims 21 to 23, wherein the mutations that increase binding affinity to human FcRn comprise M428L / N434S or M428L / N434A.

25. The antibody or antigen-binding fragment of any one of claims 21 to 24, wherein the mutations that enhance binding to FcγRs comprise S239D; I332E; A330L; G236A; or any combination thereof.

26. The antibody or antigen-binding fragment of any one of claims 21 to 25, wherein the mutations that enhance binding to FcγRs comprise: (i)S239D / I332E; (ii)S239D / A330L / I332E; (iii) G236A / S239D / I332E; or (iv) G236A / A330L / I332E, wherein the Fc polypeptide or fragment thereof optionally comprises Ser at position 239.

27. The antibody or antigen-binding fragment of any one of claims 1 to 26, comprising a mutation that alters glycosylation, wherein the mutation that alters glycosylation comprises N297A, N297Q or N297G, and / or is deglycosylated, and / or is defucosylated.

28. An anti-influenza neuraminidase (anti-NA) antibody or an antigen-binding fragment thereof, the anti-influenza neuraminidase (anti-NA) antibody or an antigen-binding fragment thereof comprising: (i) in the heavy chain, (i)(a) a variable domain (VH) comprising the complementary determining region (CDR) H1, the CDRH2 and the CDRH3 amino acid sequences set forth in SEQ ID NO.:55, 4 and 5, respectively, wherein optionally, the VH comprises or consists of an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical to the amino acid sequence set forth in SEQ ID NO.:54, and (i)(b) mutations M428L and N434S; and (ii) in the light chain, a light chain variable domain (VL) comprising the CDRL1, the CDRL2 and the CDRL3 amino acid sequences listed in SEQ ID NO.: 9-11, respectively, wherein optionally, the VL comprises or consists of an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical to the amino acid sequence listed in SEQ ID NO.:

8.

29. An anti-influenza neuraminidase (anti-NA) antibody or an antigen-binding fragment thereof, the anti-influenza neuraminidase (anti-NA) antibody or an antigen-binding fragment thereof comprising: (I)(i) in the heavy chain, (i)(a) a variable domain (VH) comprising the complementary determining region (CDR) H1, the CDRH2 and the CDRH3 amino acid sequences set forth in SEQ ID NO.:47, 4 and 5, respectively, wherein optionally, the VH comprises or consists of an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical to the amino acid sequence set forth in SEQ ID NO.:46, and (i) (b) the mutations M428L and N434S; and (ii) in the light chain, a light chain variable domain (VL) comprising the CDRL1, CDRL2 and CDRL3 amino acid sequences set forth in SEQ ID NO.: 9-11, respectively, wherein optionally, the VL comprises or consists of an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical to the amino acid sequence set forth in SEQ ID NO.: 8, (2)(i) in the heavy chain, (i)(a) a variable domain (VH) comprising the complementary determining region (CDR) H1, the CDRH2 and the CDRH3 amino acid sequences set forth in SEQ ID NO.: 3-5, respectively, wherein optionally, the VH comprises or consists of an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical to the amino acid sequence set forth in SEQ ID NO.: 65, and (i) (b) the mutations M428L and N434S; and (ii) in the light chain, a light chain variable domain (VL) comprising the CDRL1, CDRL2 and CDRL3 amino acid sequences set forth in SEQ ID NOs.: 9-10, respectively, wherein optionally, the VL comprises or consists of an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical to the amino acid sequence set forth in SEQ ID NO.: 68; or (3)(i) in the heavy chain, (i)(a) a variable domain (VH) comprising the complementary determining region (CDR) H1, the CDRH2 and the CDRH3 amino acid sequences set forth in SEQ ID NO.: 3, 57 and 5, respectively, wherein optionally, the VH comprises or consists of an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical to the amino acid sequence set forth in SEQ ID NO.: 56, and (i) (b) the mutations M428L and N434S; and (ii) in the light chain, a light chain variable domain (VL) comprising the CDRL1, the CDRL2 and the CDRL3 amino acid sequences listed in SEQ ID NO.: 9-11, respectively, wherein optionally, the VL comprises or consists of an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical to the amino acid sequence listed in SEQ ID NO.:

8.

30. The antibody or antigen-binding fragment of any one of claims 28 to 29, wherein VH and VL have at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity with the amino acid sequence set forth in SEQ ID NO., or comprise or consist of the amino acid sequence set forth in SEQ ID NO. (i) 54 and 8, respectively; (ii) 2 and 31, respectively; (iii) 2 and 8, respectively; (iv) 46 and 8, respectively; (v) 65 and 68, respectively; or (vi) 56 and 8, respectively.

31. The antibody or antigen-binding fragment according to any one of claims 28 to 30, wherein VH and VL comprise or consist of the amino acid sequence set forth in SEQ ID NO.: (i) 54 and 8, respectively; (ii) 2 and 31, respectively; (iii) 2 and 8, respectively; (iv) 46 and 8, respectively; (v) 65 and 68, respectively; or (vi) 56 and 8, respectively.

32. An antibody or antigen-binding fragment according to any one of claims 28 to 30, wherein VH and VL have at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity with the amino acid sequences listed in SEQ ID NOs.: 2 and 37, respectively, or comprise or consist of the amino acid sequences listed in SEQ ID NOs.: 2 and 37, respectively.

33. The antibody or antigen-binding fragment of any one of claims 28 to 32, comprising an IgG1m3 allotype, an IgG1m17 allotype, an IgG1m1 allotype, or any combination thereof.

34. The antibody or antigen-binding fragment of any one of claims 1 to 33, wherein the VH is contained in a heavy chain, which further comprises the CH1-CH3 amino acid sequence set forth in SEQ ID NO.: 34, SEQ ID NO.: 36 or SEQ ID NO.: 38, or comprises SEQ ID NO.: 34 with the C-terminal lysine and optionally the C-terminal glycine-lysine removed, SEQ ID NO.: 36 with the C-terminal glycine removed, or SEQ ID NO.: 38 with the C-terminal glycine removed.

35. The antibody or antigen-binding fragment of any one of claims 1 to 34, wherein the VL is contained in a light chain, which also comprises the CL amino acid sequence listed in SEQ ID NO.:

35.

36. An anti-influenza neuraminidase (anti-NA) antibody, the anti-influenza neuraminidase (anti-NA) antibody comprising: (1) (i) a heavy chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.:39, or comprising or consisting of SEQ ID NO.:39 with the C-terminal lysine removed or the C-terminal glycine-lysine removed; and (ii) a light chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.:41; (2) (i) a heavy chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.: 40, or comprising or consisting of SEQ ID NO.: 40 with the C-terminal lysine removed or the C-terminal glycine-lysine removed; and (ii) a light chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.: 41; (3) (i) a heavy chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.:42, or comprising or consisting of SEQ ID NO.:42 with the C-terminal lysine removed or the C-terminal glycine-lysine removed; and (ii) a light chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.:44; (4) (i) a heavy chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.: 43, or comprising or consisting of SEQ ID NO.: 43 with the C-terminal lysine removed or the C-terminal glycine-lysine removed; and (ii) a light chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.: 44; (5) (i) two heavy chains, each heavy chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.: 39, or comprising or consisting of SEQ ID NO.: 39 with the C-terminal lysine removed or with the C-terminal glycine-lysine removed; and (ii) two light chains, each light chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.:41; (6) (i) two heavy chains, each heavy chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.:40 or SEQ ID NO.:40 with the C-terminal glycine-lysine removed, or comprising or consisting of SEQ ID NO.:40 with the C-terminal lysine removed or with the C-terminal glycine-lysine removed; and (ii) two light chains, each light chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.:41; (7) (i) two heavy chains, each heavy chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.:42, or comprising or consisting of SEQ ID NO.:42 with the C-terminal lysine removed or with the C-terminal glycine-lysine removed; and (ii) two light chains, each chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.:44; or (8) (i) two heavy chains, each heavy chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.: 43, or comprising or consisting of SEQ ID NO.: 43 with the C-terminal lysine removed or with the C-terminal glycine-lysine removed; and (ii) two light chains, each light chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.:

44.

37. An anti-influenza neuraminidase (anti-NA) antibody or antigen-binding fragment, comprising the VH amino acid sequence listed in SEQ ID NO.:54 and the VL amino acid sequence listed in SEQ ID NO.:

8.

38. An anti-influenza neuraminidase (anti-NA) antibody or antigen-binding fragment, comprising: (i) a VH comprising or consisting of the amino acid sequence of any one of SEQ ID NO.: 2, 45, 46, 48, 50, 52, 54, 56, 58, 60, 63 and 65; and (ii) a VL comprising or consisting of the VL amino acid sequence of SEQ ID NO.:

8.

39. An anti-influenza neuraminidase (anti-NA) antibody or antigen-binding fragment, the anti-influenza neuraminidase (anti-NA) antibody or antigen-binding fragment comprising: (1)(i) VH, wherein the VH comprises the amino acid sequence and (ii) VL, The VL comprises the amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLIYDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPPWTFGQGTKVEIK (SEQ ID NO.: 8); (2)(i) VH, wherein VH has an amino acid sequence and (ii) VL consisting of the amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLIYDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPPWTFGQGTKVEIK (SEQ ID NO.: 8); (3)(i) a heavy chain comprising the VH amino acid sequence QVHLVQSGAEVKEPGSSVTVSCKASGGTFNNQAISWVRQAPGQGLEWMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAVYYCARAGSDYFNRDLGWENYYFASWGQGTLVTVSS (SEQ ID NO.: 54); and (ii) a light chain comprising the VL amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLIYDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPPWTFGQGTKVEIK (SEQ ID NO.: 8), wherein optionally the antibody or antigen-binding fragment is a (e.g., human) IgG1 isotype and optionally comprises M428L and N434S mutations, and / or wherein the light chain is an IgG1 kappa light chain; (4)(i) two heavy chains, each heavy chain comprising the VH amino acid sequence QVHLVQSGAEVKEPGSSVTVSCKASGGTFNNQAISWVRQAPGQGLEWMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAVYYCARAGSDYFNRDLGWENYYFASWGQGTLVTVSS (SEQ ID NO.: 54); and (ii) two light chains, each light chain comprising the VL amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLIYDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPPWTFGQGTKVEIK (SEQ ID NO.: 8), wherein optionally, the antibody or antigen-binding fragment is a (e.g., human) IgG1 isotype and optionally comprises M428L and N434S mutations, and / or wherein each of the light chains is an IgG1 κ light chain; (5)(i) VH, wherein the VH comprises the VH amino acid sequence QVHLVQSGAEVKEPGSSVTVSCKASGGTFNNQAISWVRQAPGQGLEWMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAVYYCARAGSDYFNRDLGWENYYFASWGQGTLVTVSS (SEQ ID NO.: 54), wherein optionally, the CDRs are defined according to IMGT; and (ii) a VL comprising CDRL1, CDRL2 and CDRL3 of the VL amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLIYDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPPWTFGQGTKVEIK (SEQ ID NO.: 8), wherein optionally, the CDRs are defined according to IMGT; (6) (i) a heavy chain comprising in VH CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence QVHLVQSGAEVKEPGSSVTVSCKASGGTFNNQAISWVRQAPGQGLEWMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAVYYCARAGSDYFNRDLGWENYYFASWGQGTLVTVSS (SEQ ID NO.: 54), wherein optionally, the CDRs are defined according to IMGT; and (ii) a light chain comprising in VL the VL amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLIYDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPPWTFGQGTKVEIK (SEQ ID NO.: 54). NO.:8), wherein optionally, the CDRs are defined according to IMGT, wherein further optionally, the antibody or antigen-binding fragment is of (e.g., human) IgG1 isotype and optionally comprises M428L and N434S mutations, and / or wherein the light chain is an IgG1κ light chain; (7) (i) two heavy chains, each comprising in VH CDRH1, CDRH2 and CDRH3 of the VH amino acid sequence QVHLVQSGAEVKEPGSSVTVSCKASGGTFNNQAISWVRQAPGQGLEWMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAVYYCARAGSDYFNRDLGWENYYFASWGQGTLVTVSS (SEQ ID NO.: 54), wherein optionally, the CDRs are defined according to IMGT; and (ii) two light chains, each comprising in VL the VL amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLIYDASTRATGFSARFAGSGSGTEFTLTISSLQSEDSAIYYCQQYNNWPPWTFGQGTKVEIK (SEQ ID NO.: 54). NO.:8), wherein optionally, the CDRs are defined according to IMGT, and wherein further optionally, the antibody or antigen-binding fragment is of (e.g., human) IgG1 isotype and optionally comprises M428L and N434S mutations, and / or wherein each of the light chains is an IgG1κ light chain; or (8) (i) two heavy chains, wherein each of the two heavy chains comprises the VH amino acid sequence listed in SEQ ID NO.: 54, and (ii) two light chains, wherein each of the two light chains comprises the amino acid sequence listed in SEQ ID NO.: 8, wherein optionally, the antibody is an IgG1 isotype, and wherein further optionally, the antibody comprises M428L and N434S mutations (EU numbering).

40. The antibody or antigen-binding fragment of any one of claims 1 to 39, comprising in its heavy chain an amino acid mutation listed in any one of (i) to (xviii): (i) G236A, L328V and Q295E; (ii) G236A, P230A and Q295E; (iii) G236A, R292P and I377N; (iv) G236A, K334A and Q295E; (v) G236S, R292P and Y300L; (vi) G236A and Y300L; (vii) G236A, R292P and Y300L; ( viii) G236S, G420V, G446E and L309T; (ix) G236A and R292P; (x) R292P and Y300L; (xi) G236A and R292P; (xii) Y300L; (xiii) E345K, G236S, L235Y and S267E; (xiv) E272R, L309T, S219Y and S267E; (xv) G236Y; (xvi) G236W; (xvii) F243L, G446E, P396L and S267E; (xviii) G236A, S239D and H268E.

41. The antibody or antigen-binding fragment of any one of claims 1 to 40, comprising the amino acid mutation G236A in its heavy chain.

42. The antibody or antigen-binding fragment of any one of claims 1 to 41, which: is defucosylated; has been produced in a host cell that is incapable of fucosylation or whose ability to fucosylate polypeptides is inhibited; has been produced under conditions that inhibit the host cell from fucosylating; or any combination thereof.

43. The antibody or antigen-binding fragment of any one of claims 1 to 42, which is human, humanized or chimeric.

44. The antibody or antigen binding fragment of any one of claims 1 to 43, which is capable of binding to NA from: (i) influenza A virus (IAV), wherein the IAV comprises a Group 1 IAV, a Group 2 IAV, or both; and (ii) Influenza B virus (IBV).

45. The antibody or antigen-binding fragment of claim 44, wherein: (i) the Group 1 IAV NA includes N1, N4, N5 and / or N8; and / or (ii) The Group 2 IAV NA includes N2, N3, N6, N7 and / or N9.

46. ​​The antibody or antigen-binding fragment of claim 45, wherein: (i) the N1 is any one or more of the following: A / California / 07 / 2009, A / California / 07 / 2009I223R / H275Y, A / California / 07 / 2009Q250S, A / Swine / Jiangsu / Jiangsu / J004 / 2018, A / Swine / Hebei / 2017, A / Stockholm / 18 / 2007, A / Brisbane / 02 / 2018, A / Michigan / 45 / 2015, A / Mississippi / 3 / 2001, A / Holland / 603 / 2009, A / Holland / 602 / 2009, A / Vietnam / 1203 / 2004, A / Vietnam / 1203 / 2004S247R, A / Vietnam / 1203 / 2004I223R, A / Vietnam / 1203 / 2004R152I, A / Vietnam / 1203 / 2004D199N, A / G4 / SW / Shandong / 1207 / 2016, A / G4 / SW / Henan / SN13 / 2018, A / G4 / SW / Jiangsu / J004 / 2018, A / Mink / Spain / 2022, and A / New Jersey / 8 / 1976; (ii) N4 is from A / Mallard / Netherlands / 30 / 2011; (iii) N5 is from A / Shui Niao / Korea / CN5 / 2009; (iv) the N8 is from A / Harbor Seal / New Hampshire / 179629 / 2011 or A / Chicken / Russia / 3-29 / 2020; (v) the N2 is any one or more of the following: A / Washington / 01 / 2007, A / Washington / 01 / 2007R292K, A / Hong Kong / 68, A / South Australia / 34 / 2019, A / Switzerland / 8060 / 2017, A / Singapore / INFIMH-16-0019 / 2016, A / Switzerland / 9715293 / 2013, A / Leningrad / 134 / 17 / 57, A / Florida / 4 / 2006, A / Netherlands / 823 / 1992, A / Norway / 466 / 2014, A / Switzerland / 8060 / 2017, A / Texas / 50 / 2012, A / Victoria / 361 / 2011, A / Hong Kong / 2671 / 2019, A / Hong Kong, China / 2671 / 2019K431E, A / SW / Mexico / SG1444 / 2011, A / Tanzania / 205 / 2010, A / Aichi / 2 / 1968, A / Bilthoven / 21793 / 1972, A / Netherlands / 233 / 1982, A / Shanghai / 11 / 1987, A / Nanchang / 933 / 1995, A / Fukui / 45 / 2004, A / Brisbane / 10 / 2007, A / Tasmania / 503 / 2020, A / Cambodia / 2020, A / Perth / 16 / 2009, A / Kansas / 14 / 2017, A / Swine / Kansas / 2021, A / Dog / Korea / VC378 / 2012, and A / Dog / Indiana / 003018 / 2016; (vi) the N3 is N3 from any one or more of the following: A / Canada / rv504 / 2004 and A / Ck / Ja / 2017; (v) the N6 is N6 from any one or more of the following: A / Swine / Ontario / 01911 / 1 / 99, A / Ck / Suzhou / 2019, and A / Hangzhou / 2021; (vi) the N7 is any one or more of the following: A / Netherlands / 078 / 03, A / Ck / 621572 / 03; (vii) the N8 is from any one or more of the following: A / Harbor Seal / New Hampshire / 179629 / 2011 and A / Ck / Russia / 2020; and / or (viii) the N9 is N9 from any one or more of the following: A / Anhui / 2013 and A / Hong Kong, China / 56 / 2015.

47. The antibody or antigen-binding fragment according to any one of claims 44 to 46, wherein the IBV NA is NA from any one or more of the following: B / Lee / 10 / 1940 (ancestor); B / Brisbane / 60 / 2008 (Victoria); B / Malaysia / 2506 / 2004 (Victoria); B / Malaysia / 3120318925 / 2013 (Yamagata); B / Wisconsin / 1 / 2010 (Yamagata); B / Yamanashi / 166 / 1998 (Yamagata); B / Brisbane / 33 / 2008; B / Colorado / 06 / 2017; B / Hubei Wujiang / 158 / 2009; B / Massachusetts / 02 / 2012; B / Netherlands / 234 / 2011; B / Perth / 211 / 2001; B / Texas / 06 / 2011 (Yamagata); B / Perth / 211 / 2011; B / Hong Kong, China / 05 / 1972; B / Phuket / 3073 / 2013, B / Harbin / 7 / 1994 (Victoria), B / Washington / 02 / 2019 (Victoria); B / Victoria / 504 / 2000 (Yamagata Prefecture); B / Victoria / 2 / 87; B / Victoria / 2 / 87 pedigree; B / Yamagata Prefecture / 16 / 88; and B / Yamagata Prefecture / 16 / 88 pedigree.

48. The antibody or antigen-binding fragment of any one of claims 1 to 47, wherein the antibody or antigen-binding fragment is capable of binding with an EC50 to each of: (i) Group 1 IAV NA; (ii) Group 2 IAV NA; and (iii) IBV NA, EC 50 In the range of about 0.1 μg / mL to about 50 μg / mL, or in the range of about 0.1 μg / mL to about 2 μg / mL, or in the range of 0.1 μg / mL to about 10 μg / mL, or in the range of 2 μg / mL to about 10 μg / mL, or in the range of about 0.4 μg / mL to about 50 μg / mL, or in the range of about 0.4 μg / mL to about 2 μg / mL, or in the range of 0.4 μg / mL to about 10 μg / mL, or in the range of 2 μg / mL to about 10 μg / mL, or in the range of 0.4 μg / mL to about 1 μg / mL, or 0.4 μg / mL or less, wherein optionally, The antibody or antigen-binding fragment is capable of: (i) at an EC in the range of about 0.4 μg / mL to about 50 μg / mL, about 0.4 μg / mL to about 10 μg / mL, about 0.4 μg / mL to about 2 μg / mL, about 2 μg / mL to about 50 μg / mL, about 2 μg / mL to about 10 μg / mL, or about 10 μg / mL to about 50 μg / mL. 50 in combination with said Group 1 IAV NA; (ii) at an EC in the range of about 0.4 μg / mL to about 50 μg / mL, or about 0.4 μg / mL to about 10 μg / mL, or about 0.4 μg / mL to about 2 μg / mL, or about 2 μg / mL to about 50 μg / mL, or about 2 μg / mL to about 10 μg / mL, or about 10 μg / mL to about 50 μg / mL. 50 in combination with said Group 2 IAV NA; and / or (iii) at an EC of about 0.4 μg / mL, or in the range of about 0.1 μg / mL to about 1.9 μg / mL, or about 0.1 μg / mL to about 1.5 μg / mL, or about 0.1 μg / mL to about 1.0 μg / mL, or about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 Binds to said IBV NA, wherein further optionally, said antibody or antigen-binding fragment is capable of: (i) at an EC of about 0.4 μg / mL, or in the range of about 0.4 μg / mL to about 50 μg / mL, or in the range of about 0.1 μg / mL to about 1.9 μg / mL, or in the range of about 0.1 μg / mL to about 1.5 μg / mL, or in the range of about 0.1 μg / mL to about 1.0 μg / mL, or about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL or 1.0 μg / mL. 50 Binds to N1; (ii) at an EC of about 0.4 μg / mL, or in the range of about 0.1 μg / mL to about 1.9 μg / mL, or about 0.1 μg / mL to about 1.5 μg / mL, or about 0.1 μg / mL to about 1.0 μg / mL, or about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 Combined with N4; (iii) at an EC in the range of about 0.4 μg / mL to about 2 μg / mL 50 Binds to N5; (iv) with an EC of about 50 μg / mL 50 Combined with N8; (v) at an EC in the range of about 0.4 μg / mL to about 20 μg / mL, or about 0.4 μg / mL to about 10 μg / mL, or about 0.4 μg / mL to about 2 μg / mL, about 1 μg / mL to about 10 μg / mL, or about 1 μg / mL to about 20 μg / mL, or about 1 μg / mL to about 5 μg / mL, or about 1 μg / mL, 2 μg / mL, 3 μg / mL, 4 μg / mL, 5 μg / mL, 6 μg / mL, 7 μg / mL, 8 μg / mL, 9 μg / mL, 10 μg / mL, 15 μg / mL, or 20 μg / mL. 50 Combined with N2; (vi) at an EC of about 0.4 μg / mL, or in the range of about 0.1 μg / mL to about 1.9 μg / mL, or about 0.1 μg / mL to about 1.5 μg / mL, or about 0.1 μg / mL to about 1.0 μg / mL, or about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 Combined with N3; (vii) at an EC of about 0.4 μg / mL, or in the range of about 0.1 μg / mL to about 1.9 μg / mL, or about 0.1 μg / mL to about 1.5 μg / mL, or about 0.1 μg / mL to about 1.0 μg / mL, or about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 Binds to N6; (viii) at an EC in the range of about 2 μg / mL to about 50 μg / mL 50 (ix) binds to N7 at an EC of about 0.4 μg / mL, or in the range of about 0.1 μg / mL to about 1.9 μg / mL, or about 0.1 μg / mL to about 1.5 μg / mL, or about 0.1 μg / mL to about 1.0 μg / mL, or about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 Combined with N9; and / or (xi) at an EC of about 0.4 μg / mL, or in the range of about 0.1 μg / mL to about 1.9 μg / mL, or about 0.1 μg / mL to about 1.5 μg / mL, or about 0.1 μg / mL to about 1.0 μg / mL, or about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 Binding to IBV NA.

49. The antibody or antigen-binding fragment of claim 48, wherein the antibody or antigen-binding fragment is capable of: (i) at an EC of about 0.4 μg / mL, or in the range of about 0.1 μg / mL to about 1.9 μg / mL, or about 0.1 μg / mL to about 1.5 μg / mL, or about 0.1 μg / mL to about 1.0 μg / mL, or about 0.1 μg / mL, 0.2 μg / mL, 0.3 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 0.6 μg / mL, 0.7 μg / mL, 0.8 μg / mL, 0.9 μg / mL, or 1.0 μg / mL. 50 Combined with one or more of the following: N1 A / California / 07 / 2009, N1 A / California / 07 / 2009I223R / H275Y, N1 A / Stockholm / 18 / 2007, N1 A / Pig / Jiangsu / Jiangsu / J004 / 2008, N4 A / Mallard / Netherlands / 30 / 2011, N5 A / Waterfowl / Korea / CN5 / 2009, N2 A / Hong Kong, China / 68, N2 A / Leningrad / 134 / 17 / 57, N3 A / Canada / rv504 / 2004, N6 A / Pig / Ontario / 01911 / 1 / 99, N9 A / Anhui / 1 / 2013, B / Lee / 10 / 1940 (ancestor), B / Brisbane / 60 / 2008 (Victoria), B / Malaysia / 2506 / 2004 (Victoria), B / Malaysia / 3120318925 / 2013 (Yamagata), B / Wisconsin / 1 / 2010 (Yamagata) and B / Yamanashi / 166 / 1998 (Yamagata); (ii) at an EC of about 2 μg / mL or in a range of about 2 μg / mL to about 10 μg / mL 50 Combined with N5 A / Waterbird / Korea / CN5 / 2009; (iii) With an EC of about 50 μg / mL 50 Combined with N8 A / Harbor Seals / New Hampshire / 179629 / 2011; (iv) at an EC in the range of about 2 μg / mL to about 10 μg / mL 50 Combined with N2 A / Washington / 01 / 2007; (v) at an EC in the range of about 2 μg / mL to about 50 μg / mL 50 Combined with N7 A / Netherlands / 078 / 03; (vi) at an EC in the range of about 0.4 μg / mL to about 50 μg / mL 50 Combined with N2 A / South Australia / 34 / 2019; (vii) at an EC in the range of about 9.5 μg / mL to about 3.8 μg / mL 50 Combined with N2 A / Switzerland / 8060 / 2017; (viii) at an EC in the range of about 18.4 μg / mL to about 2.2 μg / mL 50 Combined with N2 A / Singapore / INFIMH-16-0019 / 2016; (iv) at an EC in the range of about 1.6 μg / mL to about 1.2 μg / mL 50 in combination with N2 A / Switzerland / 9715293 / 2013; and / or (v) at an EC in the range of about 0.4 μg / mL to about 50 μg / mL, or about 0.4 μg / mL, about 2 μg / mL, about 10 μg / mL, or about 50 μg / mL 50 Combined with N1 A / Pig / Jiangsu / Jiangsu / J004 / 2018.

50. The antibody or antigen-binding fragment of any one of claims 1 to 49, wherein the NA is expressed on the surface of a host cell (e.g., a CHO cell) and the binding to the NA is by flow cytometry, and / or wherein the antibody or antigen-binding fragment is capable of binding to the NA with a KD of less than 1.0E-12M, less than 1.0E-11M, less than 1.0E-11M, or 1.0E-12M or less, 1.0E-11M or less, or 1.0E-10 or less, or a KD between 1.0E-10 and 1.0E-13, or a KD between 1.0E-11 and 1.0E-13, wherein optionally, the binding is assessed by biolayer interferometry (BLI).

51. The antibody or antigen-binding fragment of claim 50, wherein the NA is N1, N2 and / or N9.

52. The antibody or antigen-binding fragment of any one of claims 1 to 51, which is capable of binding to: (1) (i) a NA epitope comprising any one or more of the following amino acids (N1 NA numbering): R368, R293, E228, E344, S247, D198, D151, R118; and / or (ii) a NA epitope comprising any one or more of the following amino acids (N2 NA numbering): R371, R292, E227, E344, S247, D198, D151, R118; and / or (2) (i) a NA epitope comprising amino acids R368, R293, E228, D151 and R118 (N1 NA numbering); and / or (ii) a NA epitope comprising amino acids R371, R292, E227, D151 and R118 (N2 NA numbering); and / or (3) an epitope contained in or comprising the NA active site, wherein optionally, the NA active site comprises the following amino acids (N2 numbering): R118, D151, R152, R224, E276, R292, R371, Y406, E119, R156, W178, S179, D / N198, I222, E227, H274, E277, D293, E425; and / or (4) an IBV NA epitope comprising: (i) any one or more of the following amino acids: R116, D149, E226, R292, and R374; or (ii) amino acids R116, D149, E226, R292 and R374, wherein optionally, (a) the epitope further comprises any one or more of the following NA amino acids (N2 numbering): E344, E227, S247 and D198; and / or (b) The antibody or antigen-binding fragment is capable of binding to NA comprising an S245N amino acid mutation and / or an E221D amino acid mutation.

53. The antibody or antigen-binding fragment according to any one of claims 1 to 52, which is capable of binding to NA comprising an S245N amino acid mutation and / or an E221D amino acid mutation.

54. The antibody or antigen-binding fragment of any one of claims 1 to 53, wherein the antibody or antigen-binding fragment is capable of inhibiting the following sialidase activity in an in vitro infection model, an in vivo infection animal model, and / or in humans: (i) IAV NA, wherein the IAV NA comprises Group 1 IAV NA, Group 2 IAV NA, or both, and / or (ii) IBV NA, wherein optionally: (1) The Group 1 IAV NA includes H1N1 and / or H5N1; (2) the Group 2 IAV NA includes H3N2 and / or H7N9; and / or (3) The IBV NA includes one or more of the following: B / Lee / 10 / 1940 (ancestor); B / Hong Kong, China / 05 / 1972; B / Taiwan, China / 2 / 1962 (ancestor); B / Brisbane / 33 / 2008 (Victoria); B / Brisbane / 60 / 2008 (Victoria); B / Malaysia / 2506 / 2004 (Victoria); B / New York / 1056 / 2003 (Victoria); B / Florida / 4 / 2006 (Yamagata); B / Jiangsu / 10 / 2003(Yamagata Prefecture); B / Texas / 06 / 2011(Yamagata Prefecture); B / Perth / 211 / 2011; B / Harbin / 7 / 1994 (Victoria); B / Colorado / 06 / 2017 (Victoria); B / Washington / 02 / 2019 (Victoria); B / Perth / 211 / 2001 (Yamagata Prefecture); B / Hubei Wujiagang / 158 / 2009 (Yamagata Prefecture); B / Wisconsin / 01 / 2010 (Yamagata Prefecture); B / Massachusetts / 02 / 2012 (Yamagata Prefecture); and B / Phuket / 3073 / 2013 (Yamagata Prefecture).

55. The antibody or antigen binding fragment of any one of claims 1 to 54, wherein the antibody or antigen binding fragment is capable of inhibiting the sialidase activity of Group 1 IAV NA, Group 2 IAV NA and / or IBV NA with a certain IC50, The IC50 about 0.0008 μg / mL to about 4 μg / mL, about 0.0008 μg / mL to about 3 μg / mL, about 0.0008 μg / mL to about 2 μg / mL, about 0.0008 μg / mL to about 1 μg / mL, about 0.0008 μg / mL to about 0.9 μg / mL, about 0.0008 μg / mL to about 0.8 μg / mL, about 0.0008 μg / mL to about 0.7 μg / mL, about 0.0008 μg / mL to about 0.6 μg / mL, about 0.0008 μg / mL to about 0.5 μg / mL, about 0.0008 μg / mL to about 0.4 μg / mL, about 0.0008 μg / mL to about 0.3 μg / mL, about 0.0008 μg / mL to about 0.2 μg / mL, about 0.0008 μg / mL to about 0.1 μg / mL, about 0.0008 μg / mL to about 0.09 μg / mL, about 0.0008 μg / mL to about 0.08 μg / mL, about 0.0008 μg / mL to about 0.07 μg / mL, about 0.0008 μg / mL to about 0.06 μg / mL, about 0.0008 μg / mL to about 0.05 μg / mL, about 0.0008 μg / mL to about 0.04 μg / mL, about 0.0008 μg / mL to about 0.03 μg / mL, about 0.0008 μg / mL to about 0.02 μg / mL, about 0.0008 μg / mL to about 0. / mL to about 0.01 μg / mL, 0.002 μg / mL to about 4 μg / mL, about 0.001 μg / mL to 50 μg / mL, about 0.1 μg / mL to about 30 μg / mL, about 0.1 μg / mL to about 20 μg / mL, about 0.1 μg / mL to about 10 μg / mL, about 0.1 μg / mL to about 9 μg / mL, about 0.1 μg / mL to about 8 μg / mL, about 0.1 μg / mL to about 7 μg / mL, about 0.1 μg / mL to about 6 μg / mL, about 0.1 μg / mL to about 5 μg / mL, about 0.1 μg / mL to about 4 μg / mL, about 0.1 μg / mL to about 3 μg / mL, about 0.1 μg / mL to about 2 μg / mL, about 0.1 μg / mL to about 1 μg / mL, about 0.1 μg / mL to about 0.9 μg / mL, about 0.1 μg / mL to about 0.8 μg / mL, about 0.1 μg / mL to about 0.7 μg / mL, about 0.1 μg / mL to about 0.6 μg / mL, about 0.1 μg / mL to about 0.5 μg / mL, about 0.1 μg / mL to about 0.4 μg / mL, about 0.1 μg / mL to about 0.3 μg / mL, about 0.1 μg / mL to about 0.2 μg / mL, about 0.8 μg / mL to about 30 μg / mL, about 0.8 μg / mL to about 20 μg / mL, about 0.8 μg / mL to about 10 μg / mL, about 0.In some embodiments, the present invention relates to an agent that is in the range of about 0.8 μg / mL to about 9 μg / mL, about 0.8 μg / mL to about 8 μg / mL, about 0.8 μg / mL to about 7 μg / mL, about 0.8 μg / mL to about 6 μg / mL, about 0.8 μg / mL to about 5 μg / mL, about 0.8 μg / mL to about 4 μg / mL, about 0.8 μg / mL to about 3 μg / mL, about 0.8 μg / mL to about 2 μg / mL, about 0.8 μg / mL to about 1 μg / mL, or about 0.1 μg / mL, about 0.2 μg / mL, about 0.3 μg / mL, about 0.4 μg / mL, about 0.5 μg / mL, about 0.6 μg / mL, about 0.7 μg / mL, about 0.8 μg / mL, about 0.9 μg / mL, about 1.0 μg / mL, about 1.5 μg / mL, about 2 about 2.0 μg / mL, about 2.5 μg / mL, about 3.0 μg / mL, about 3.5 μg / mL, about 4.0 μg / mL, about 4.5 μg / mL, about 5.0 μg / mL, about 5.5 μg / mL, about 6.0 μg / mL, about 6.5 μg / mL, about 7.0 μg / mL, about 7.5 μg / mL, about 8.0 μg / mL, about 8.5 μg / mL L, about 9.0 μg / mL, about 10 μg / mL, about 11 μg / mL, about 12 μg / mL, about 13 μg / mL, about 14 μg / mL, about 15 μg / mL, about 16 μg / mL, about 17 μg / mL, about 18 μg / mL, about 19 μg / mL, about 20 μg / mL, about 25 μg / mL and / or about 30 μg / mL, wherein optionally,. The antibody or antigen-binding fragment is capable of inhibiting the NA sialidase activity of one or more Group 1 and / or Group 2 IAVs and / or one or more IBVs with an IC50 between about 0.00001 μg / ml and about 25 μg / ml, or about 0.0001 μg / ml and about 10 μg / ml, or about 0.0001 μg / ml and about 1 μg / ml, or about 0.0001 μg / mL and about 0.1 μg / mL, or about 0.0001 μg / mL and about 0.01 μg / mL, or about 0.0001 μg / mL and about 0.001 μg / mL. l, or about 0.0001 μg / ml to about 0.0001 μg / ml, or about 0.0001 μg / ml to about 25 μg / ml, or about 0.0001 μg / ml to about 10 μg / ml, or about 0.0001 μg / ml to about 1 μg / ml, or about 0.0001 μg / ml to about 0.1 μg / ml, or about 0.0001 μg / ml to about 0.01 μg / ml, or about 0.001 μg / ml to about 25 μg / ml, or about 0.001 μg / ml to about 10 μg / ml, or about 0.001 μg / ml to about 1 μg / ml l, or about 0.001 μg / ml to about 0.1 μg / ml, or about 0.001 μg / ml to about 0.01 μg / ml, or about 0.01 μg / ml to about 25 μg / ml, or about 0.01 μg / ml to about 10 μg / ml, or about 0.01 μg / ml to about 1 μg / ml, or about 0.01 μg / ml to about 0.1 μg / ml, or about 1 μg / ml to about 25 μg / ml, or about 1 μg / ml to about 10 μg / ml, or about 1 μg / ml, 1.5 μg / ml, 2 μg / ml, 2.5 μg / ml, 3 μg / ml, 3.5μg / ml, 4μg / ml, 4.5μg / ml, 5μg / ml, 5.5μg / ml, 6μg / ml, 6.5μg / ml, 7μg / ml, 7.5μg / ml, 8μg / ml, 8.5μg / ml, 9μg / ml, 9. 5μg / ml, 10μg / ml, 10.5μg / ml, 11μg / ml, 11.5μg / ml, 12μg / ml, 12.5μg / ml, 13μg / ml, 13.5μg / ml, 14μg / ml, 14.5μg / ml or 15μg / ml.

56. The antibody or antigen-binding fragment according to any one of claims 1 to 55, which is capable of activating human FcγRIIIa, wherein optionally, Activation is determined after incubation (e.g., 23 hours) of the antibody or antigen-binding fragment with target cells infected with IAV (e.g., A549 cells) using host cells (optionally, Jurkat cells), the host cells comprising: (i) the human FcγRIIIa (optionally, the F158 allele); and (ii) a NF AT expression control sequence operably linked to a sequence encoding a reporter gene such as a luciferase reporter gene, wherein further optionally, Activation is determined after incubation (optionally, for about 23 hours) of said antibody or antigen-binding fragment with said target cells infected with H1N1 IAV, wherein optionally said H1N1 IAV is A / PR8 / 34, and / or wherein optionally said infection has a multiplicity of infection (MOI) of 6.

57. The antibody or antigen-binding fragment of any one of claims 1 to 56, which is capable of neutralizing infection caused by IAV and / or IBV, wherein optionally, the IAV and / or the IBV are resistant to antiviral drugs, wherein optionally, the antiviral drug is oseltamivir.

58. The antibody or antigen-binding fragment of any one of claims 44 to 57, wherein: (1) The IAV comprises an N1 NA having the following amino acid mutation: H275Y; E119D+H275Y; S247N+H275Y; I222V; and / or N294S, wherein optionally, the IAV comprises CA09 or A / Aichi Prefecture; and / or (2) the IAV comprises an N2 NA having amino acid mutations E119V, Q136K and / or R292K.

59. The antibody or antigen-binding fragment of any one of claims 1 to 58, wherein the antibody or antigen-binding fragment is capable of: (1) treating and / or preventing (i) IAV infection and / or (ii) IBV infection in a subject; and / or (2) treating and / or alleviating infection caused by: (i) H1N1 virus, wherein optionally, the H1N1 virus comprises A / PR8 / 34; and / or (ii) H3N2 virus, wherein optionally, the H3N2 virus optionally comprises A / Hong Kong, China / 68; and / or ( 3) preventing weight loss in a subject infected with said IAV and / or said IBV, optionally for (i) up to 15 days or (ii) more than 15 days after administration of an effective amount of said antibody or antigen-binding fragment; and / or (4) preventing weight loss of greater than 10% in a subject with IAV infection and / or IBV infection, as determined by reference to the subject's weight just prior to said IAV infection and / or said IBV infection; and / or (5) prolonging the survival of a subject with IAV infection and / or IBV infection.

60. The antibody or antigen-binding fragment of any one of claims 1 to 59, wherein the antibody or antigen-binding fragment has an in vivo half-life in a mouse (e.g., a tg32 mouse): (i) in the range of about 10 days to about 14 days, about 10.2 days to about 13.8 days, about 10.5 days to about 13.5 days, about 11 days to about 13 days, about 11.5 days to about 12.5 days, between 10 days and 14 days, or between 10.5 days and 13.5 days, or between 11 days and 13 days, or about 10.0 days, 10.1 days, 10.2 days, 10.5 days, 11.5 days, 12.5 days, or about 10.0 days, 10.1 days, 11.5 days, 12.5 days, or about 10.0 days, 10.2 ... 10.2 days, 10.3 days, 10.4 days, 10.5 days, 10.6 days, 10.7 days, 10.8 days, 10.9 days, 11.0 days, 11.1 days, 11.2 days, 11.3 days, 11.4 days, 11.5 days, 11.6 days, 11.7 days, 11.8 days, 11.9 days, 12.0 days, 12.1 days, 12.2 days, 12.3 days, 12.4 days, 12.5 days, 12.6 days, 12.7 days, 12.8 days, 12.9 days, 13.0 days, 13.1 days, 13.2 days, 13.3 days, 13.4 days, 13.5 days, 13.6 days, 13.7 days, 13.8 days, 13.9 days or 14.0 days; or (ii) within the range of about 12 days to about 16 days, about 12.5 days to 15.5 days, about 13 days to 15 days, about 13.5 days to about 14.5 days, or between 12 days and 16 days, or between 13 days and 15 days, or between 13.5 days and 14.5 days, or about 12.0 days, 12.1 days, 12.2 days, 12.3 days, 12.4 days, 12.5 days, 12.6 days, 12.7 days, 12.8 days, 12.9 days, 13.0 days, 13.1 days, 13.2 days, 13.3 days, 13.4 days, 13.5 days, 1.36 days, 13.7 days, 13.8 days, 13.9 days, 14.0 days, 14.1 days, 14.2 days, 14.3 days, 14.4 days, 14.5 days, 14.6 days, 14.7 days, 14.8 days, 14.9 days, 15.0 days, 15.1 days, 15.2 days, 15.3 days, 15.4 days, 15.5 days, 1.56 days, 15.7 days, 15.8 days, 15.9 days or 16.0 days.

61. The antibody or antigen-binding fragment of claim 59 or 60, wherein the antibody or antigen-binding fragment is capable of binding to neuraminidase (NA) from: (i) influenza A virus (IAV), wherein the IAV comprises Group 1 IAV, Group 2 IAV or both; and / or (ii) influenza B virus (IBV), and wherein optionally, the antibody or antigen-binding fragment is capable of (1) inhibiting NA sialidase activity and / or (2) neutralizing infection caused by the IAV and / or the IBV.

62. An antibody comprising: (1)(i) a heavy chain comprising the amino acid sequence QVHLVQSGAEVKEPGSSVTVSCKASGGTFNNQAIS WVRQAPGQGLEWMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAVYYCARAGSDYFNRDLGWENYYFASWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNV NHKPSNTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVE WESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSR WQQGNVFSCSVLHEALHSHYTQKSLSLSPGK (SEQ ID NO.: 107) or SEQ ID NO.: 107 with the C-terminal lysine or the C-terminal glycine-lysine removed; and (ii) a light chain comprising the amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLIYDASTRATGFSARFAGSSGTEFTLTISSLQSEDSAIYYCQQYNNWPPWTFGQGTKVEIKR TVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC(SEQ IDNO.:108); (2)(i) a heavy chain, the heavy chain comprising an amino acid sequence QVHLVQSGAEVKEPGSSVTVSCKASGGTFNNQAISWVRQAPGQGLEWMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAVYYCARAGSDYFNRDLGWENYYFA SWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCD KTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVLHEALHSHYTQKSLSLSPGK (SEQID NO.: 107) or SEQID NO.: 107 with the C-terminal lysine or the C-terminal glycine-lysine removed; and (ii) a light chain, the light chain consisting of the amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLIYDASTRATGFSARFAGSSGTEFTLTISSLQSEDSAIYYCQQYNNWPPWTFGQGTKVEIKR TVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC(SEQ IDNO.:108) composition; (3)(i) two heavy chains, wherein each of the two heavy chains comprises the amino acid sequence QVHLVQSGAEVKEPGSSVTVSCKASGGTFNNQAISWVRQAPGQGLEWMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAVYYCARAGSDYFNRDLGWENYYFA SWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCD KTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVLHEALHSHYTQKSLSLSPGK (SEQ ID NO.: 107) or SEQ ID NO.: 107 with the C-terminal lysine or the C-terminal glycine-lysine removed; and (ii) two light chains, wherein each of the two light chains comprises the amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLIYDASTRATGFSARFAGSSGTEFTLTISSLQSEDSAIYYCQQYNNWPPWTFGQGTKVEIKR TVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC(SEQ IDNO:108); or (4)(i) two heavy chains, wherein each of the two heavy chains has an amino acid sequence QVHLVQSGAEVKEPGSSVTVSCKASGGTFNNQAISWVRQAPGQGLEWMGGIFPISGTPTSAQRFQGRVTFTADESTTTVYMDLSSLRSDDTAVYYCARAGSDYFNRDLGWENYYFA SWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCD KTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVLHEALHSHYTQKSLSLSPGK (SEQID NO.: 107) or SEQID NO.: 107 with the C-terminal lysine or the C-terminal glycine-lysine removed; and (ii) two light chains, wherein each of the two light chains consists of the amino acid sequence EIVMTQSPATLSLSSGERATLSCRASRSVSSNLAWYQQKPGQAPRLLIYDASTRATGFSARFAGSSGTEFTLTISSLQSEDSAIYYCQQYNNWPPWTFGQGTKVEIKR TVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC(SEQ IDNO.:108) composition.

63. An isolated polynucleotide encoding the antibody or antigen-binding fragment according to any one of claims 1 to 62, or encoding the VH, Fd, heavy chain, VL and / or light chain of the antibody or the antigen-binding fragment, wherein optionally: (1) the heavy chain comprises or consists of SEQ ID NO.: 107 or SEQ ID NO.: 107 with the C-terminal lysine or C-terminal glycine removed; (2) the light chain comprises or consists of SEQ ID NO.: 108; (3) the polynucleotide comprises SEQ ID NO.: 109; (4) the polynucleotide comprises SEQ ID NO.: 110; NO.:110; (5) the polynucleotide comprises deoxyribonucleic acid (DNA) or ribonucleic acid (RNA), wherein the RNA optionally comprises messenger RNA (mRNA); and / or (6) the polynucleotide comprises modified nucleosides, cap-1 structures, cap-2 structures or any combination thereof, wherein further optionally, the polynucleotide comprises pseudouridine, N6-methyladenosine, 5-methylcytidine, 2-thiouridine or any combination thereof, wherein further optionally, the pseudouridine comprises N1-methylpseudouridine.

64. The polynucleotide of claim 63, which is codon-optimized for expression in a host cell, wherein optionally, the host cell comprises a human cell.

65. A recombinant vector comprising a polynucleotide according to claim 63 or 64, wherein optionally, the polynucleotide encodes: (1) SEQ ID NO.: 107, or SEQ ID NO.: 107 with the C-terminal lysine or the C-terminal glycine-lysine removed; and (2) SEQ ID NO.: 108, wherein further optionally, the vector comprises SEQ ID NO.: 109 and SEQ ID NO.:

110.

66. A host cell comprising a polynucleotide according to claim 63 or 64 and / or a vector according to claim 65, wherein the polynucleotide is optionally heterologous to the host cell and / or wherein the host cell is capable of expressing the encoded antibody or antigen-binding fragment or polypeptide.

67. An isolated human B cell comprising a polynucleotide according to claim 63 or 64 and / or a vector according to claim 65, wherein the polynucleotide is optionally heterologous to the human B cell and / or wherein the human B cell is immortalized.

68. A composition comprising: (i) the antibody or antigen-binding fragment of any one of claims 1 to 62; (ii) a polynucleotide according to claim 63 or 64; (iii) the recombinant vector according to claim 65; (iv) the host cell according to claim 66; and / or (v) the human B cell according to claim 67, and a pharmaceutically acceptable excipient, carrier or diluent, Wherein optionally: (1) The composition comprises a first antibody or antigen-binding fragment and a second antibody or antigen-binding fragment, wherein the first antibody or antigen-binding fragment and the second antibody or antigen-binding fragment are each different and each is according to any one of claims 1 to 62; (2) the polynucleotide encodes: (i) SEQ ID NO.: 107 or SEQ ID NO.: 107 with the C-terminal lysine or C-terminal glycine-lysine removed, and (ii) SEQ ID NO.: 108, and the polynucleotide further optionally comprises SEQ ID NO.: 109 and SEQ ID NO.: 110; (3) The composition comprises: (i) a first polynucleotide encoding SEQ ID NO.: 107 or SEQ ID NO.: 107 with the C-terminal lysine or C-terminal glycine-lysine removed, wherein further optionally, the first polynucleotide comprises SEQ ID NO.: 109, and (ii) a second polynucleotide encoding SEQ ID NO.: 108, wherein further optionally, the second polynucleotide comprises SEQ ID NO.: 110; or (4) The composition comprises: (1) a first plasmid or vector, comprising a polynucleotide encoding SEQ ID NO.: 107 or SEQ ID NO.: 107 with the C-terminal lysine or C-terminal glycine-lysine removed, wherein further optionally, the polynucleotide comprises SEQ ID NO.: 109, and (2) a second plasmid or vector, comprising a polynucleotide encoding SEQ ID NO.: 108, wherein further optionally, the polynucleotide comprises SEQ ID NO.:

110.

69. A composition comprising a polynucleotide according to claim 63 or 64 or a vector according to claim 65 encapsulated in a carrier molecule, wherein the carrier molecule optionally comprises a lipid, a lipid-derived delivery vehicle, such as a liposome, a solid lipid nanoparticle, an oily suspension, a submicron lipid emulsion, a lipid microbubble, a reverse lipid micelle, a cochlear liposome, a lipid microtubule, a lipid microcylinder, a lipid nanoparticle (LNP) or a nanoscale platform.

70. The polynucleotide of claim 63 or 64, the vector of claim 65 or the composition of claim 68 or 69, comprising: (1) A first polynucleotide (e.g., mRNA) and a second polynucleotide (e.g., mRNA), the first polynucleotide encodes an antibody heavy chain comprising the VH listed in SEQ ID NO.: 54, and the second polynucleotide encodes an antibody light chain comprising the VL listed in SEQ ID NO.: 8; or (2) A first polynucleotide (e.g., mRNA) and a second polynucleotide (e.g., mRNA), wherein the first polynucleotide encodes the mRNA as shown in SEQ ID NO.: (i) an antibody heavy chain comprising the CDRH1, CDRH2 and CDRH3 sequences listed in 55, 4 and 5, and the second polynucleotide encodes an antibody light chain comprising the CDRL1, CDRL2 and CDRL3 sequences listed in SEQ ID NO.: 9-11, respectively.

71. A method for preparing an antibody or antigen-binding fragment according to any one of claims 1 to 62, the method comprising culturing a host cell according to claim 65 or a human B cell according to claim 66 for a period of time under conditions sufficient for the host cell or human B cell to express the antibody or antigen-binding fragment, respectively, wherein optionally, the method further comprises isolating the antibody or antigen-binding fragment.

72. A method of treating or preventing an IAV infection and / or an IBV infection in a subject, the method comprising administering to the subject an effective amount of: (i) the antibody or antigen-binding fragment of any one of claims 1 to 62; (ii) a polynucleotide according to any one of claims 63, 64 and 70; (iii) the recombinant vector according to claim 65 or 70; (iv) the host cell according to claim 66; (v) the human B cell according to claim 67; and / or (vi) A composition according to any one of claims 68 to 70.

73. The method of claim 72, wherein: (1) the antibody or antigen-binding fragment is administered to the subject at a dose of about 3 mg / kg, about 0.9 mg / kg, or about 0.3 mg / kg; and / or (2) the IAV infection is H5N1 and / or H7N9 infection.

74. A method of treating or preventing influenza infection in a human subject, the method comprising administering to the subject a polynucleotide according to claim 63, 64 or 70, a recombinant vector according to claim 65 or 70, or a composition according to any one of claims 68 to 70, wherein the polynucleotide comprises mRNA, wherein optionally, the influenza infection comprises an IAV infection and / or an IBV infection.

75. The method of any one of claims 72 to 74, comprising: (1) administering a single dose of the antibody or antigen-binding fragment, the polypeptide, the polynucleotide, the recombinant vector, the host cell or the composition to the subject; or (2) administering two or more doses of the antibody or antigen-binding fragment, the polypeptide, the polynucleotide, the recombinant vector, the host cell or the composition to the subject.

76. The method of any one of claims 72 to 75, comprising: (1) optionally administering a dose of the antibody or antigen-binding fragment, the polypeptide, the polynucleotide, the recombinant vector, the host cell or the composition to the subject once a year before or during the influenza season; or (2) administering a dose of the antibody or antigen-binding fragment, the polypeptide, the polynucleotide, the recombinant vector, the host cell or the composition to the subject twice or more a year; for example, about once every 6 months.

77. The method of any one of claims 72 to 76, comprising administering the antibody or antigen-binding fragment, the polypeptide, the polynucleotide, the recombinant vector, the host cell or the composition intramuscularly, subcutaneously or intravenously.

78. The method of any one of claims 72 to 77, wherein: (1) the treatment and / or prevention includes post-exposure prophylaxis; and / or (2) The subject has received, is receiving, or will receive an antiviral drug, wherein optionally, the antiviral drug includes a neuraminidase inhibitor, an influenza polymerase inhibitor, or both, wherein further optionally, the antiviral drug includes oseltamivir, zanamivir, baloxavir, peramivir, laninamivir, or any combination thereof.

79. An antibody or antigen-binding fragment according to any one of claims 1 to 62, a polynucleotide according to claims 63, 64 and 70, a recombinant vector according to claim 65 or 70, a host cell according to claim 66, a human B cell according to claim 67 and / or a composition according to any one of claims 68 to 70, for use in a method of treating or preventing IAV infection and / or IBV infection in a subject.

80. An antibody or antigen-binding fragment according to any one of claims 1 to 62, a polynucleotide according to claims 63, 64 and 70, a recombinant vector according to claim 65 or 70, a host cell according to claim 66, a human B cell according to claim 67 and / or a composition according to any one of claims 68 to 70, for the preparation of a medicament for treating or preventing IAV infection and / or IBV infection in a subject.

81. A method for in vitro diagnosis of IAV infection and / or IBV infection, the method comprising: (i) contacting a sample from a subject with the antibody or antigen-binding fragment according to any one of claims 1 to 62; as well as (ii) detecting a complex comprising an antigen and the antibody, or a complex comprising an antigen and the antigen-binding fragment.

82. The method according to any one of claims 72 to 78 and 81, or for the antibody or antigen-binding fragment, the polypeptide, the polynucleotide, the recombinant vector, the host cell, the human B cell and / or the composition according to any one of claims 79 and 80, wherein: (i) the IAV comprises Group 1 IAV, Group 2 IAV, or both, wherein optionally, the Group 1 IAV NA comprises N1, N4, N5, and / or N8; and / or the Group 2 IAV NA comprises N2, N3, N6, N7, and / or N9, wherein further optionally, the N1 is from A / California / 07 / 2009, from A / California / 07 / 2009I223R / H275Y, from A / California / 07 / 2009Q250S, from A / Swine / Jiangsu / Jiangsu / J004 / 2018, from A / Swine / Hebei / 2017, from A / Stockholm / 18 / 2007, from A / Brisbane / 02 / 2018, from A / Michigan / 45 / 2015, from A / Mississippi / 3 / 2001, from A / Netherlands / 603 / 2009, from A / Netherlands / 602 / 2009, from A / Vietnam / 1203 / 2004, from A / Vietnam / 1203 / 2004S247R, from A / Vietnam / 1203 / 2004I223R, from A / Vietnam / 1203 / 2004R152I, from A / Vietnam / 1203 / 2004D199N, from A / G4 / SW / Shandong / 1207 / 2016, from A / G4 / SW / Henan / SN13 / 2018, from A / G4 / SW / Jiangsu / J004 / 2018, from A / Mink / Spain / 2022, and / or from A / New Jersey / 8 / 1976; the N4 is from A / Mallard / Netherlands / 30 / 2011; the N5 is from A / Waterfowl / Korea / CN5 / 2009; the N8 is from A / Harbor Seal / New Hampshire / 179629 / 2011 and / or from A / Chicken / Russia / 3-29 / 2020;The N2 is from A / Washington / 01 / 2007, from A / Hong Kong / 68, from A / Hong Kong / 2671 / 2019, from A / Hong Kong / 2671 / 2019K431E, from A / South Australia / 34 / 2019, from A / Switzerland / 8060 / 2017, from A / Singapore / INFIMH-16-0019 / 2016, from A / Switzerland / 9715293 / 2013, from A / Leningrad / 134 / 17 / 57, from A / Florida / 4 / 2006, from A / Netherlands / 823 / 1992, from A / Norway / 466 / 2014, from A / Texas / 50 / 2012, from A / Victoria / 361 / 2011, from A / SW / Mexico / SG1444 / 2011, from A / Aichi / 2 / 1968, from A / Bilthoven / 21793 / 1972, from A / Netherlands / 233 / 1982, from A / Shanghai / 11 / 1987, from A / South Chang / 933 / 1995, from A / Fukui / 45 / 2004, A / Brisbane / 10 / 2007, from A / Tanzania / 205 / 2010, from A / Cambodia / 2020, from A / Perth / 16 / 2009, from A / Kansas / 14 / 2017, from A / Swine / Kansas / 2021, from A / Dog / Korea / VC378 / 2012, and / or from A / Dog / Indiana / 003018 / 2016; said N3 is from A / Canada / r v504 / 2004 and / or from A / Chicken / Jalisco / PAVX17170 / 2017; the N6 is from A / Pig / Ontario / 01911 / 1 / 99, from A / Ck / Suzhou / j6 / 2019, and / or from A / Hangzhou / 01 / 2021; the N7 is from A / Netherlands / 078 / 03 and / or from A / Ck / 621572 / 03; and / or the N9 is from A / Anhui / 2013, from A / Hong Kong, China / 56 / 2015; and / or; (ii) the IBV NA is from: B / Lee / 10 / 1940 (ancestor); B / Brisbane / 60 / 2008 (Victoria); B / Malaysia / 2506 / 2004 (Victoria); B / Malaysia / 3120318925 / 2013 (Yamagata Prefecture); B / Wisconsin / 1 / 2010 (Yamagata Prefecture); B / Yamanashi / 166 / 1998 (Yamagata Prefecture); B / Brisbane / 33 / 2008 (Victoria); B / Colorado / 06 / 2017 (Victoria); B / Hubei Wujiang / 158 / 2009 (Yamagata Prefecture); B / Massachusetts / 02 / 2012 (Yamagata Prefecture); B / Netherlands / 234 / 2011; B / Perth / 211 / 2001 (Yamagata Prefecture); B / Phuket / 3073 / 2013 (Yamagata Prefecture); B / Texas / 06 / 2011 (Yamagata Prefecture); B / Hong Kong, China / 05 / 1972; B / Harbin / 7 / 1994 (Victoria); B / Washington / 02 / 2019 (Victoria); B / Perth / 211 / 2011; B / Victoria / 2 / 87; B / Victoria / 2 / 87 Pedigree; B / Yamagata Prefecture / 16 / 88; B / Yamagata Prefecture / 16 / 88 Pedigree or any combination thereof.

83. A method of treating or preventing influenza infection in a subject, the method comprising administering to the subject an antibody or antigen-binding fragment at a dose of about 3 mg / kg, about 0.9 mg / kg, or about 0.3 mg / kg, or administering to the subject a composition comprising the antibody or antigen-binding fragment at a dose of about 3 mg / kg, about 0.9 mg / kg, or about 0.3 mg / kg, wherein: (i) the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 amino acid sequences of the antibody or antigen-binding fragment are as set forth in SEQ ID NOs.: 55, 4, 5 and 9-11, respectively; (ii) the VH of the antibody or antigen-binding fragment comprises the CDRH1, the CDRH2 and the CDRH3 of the VH amino acid sequence listed in SEQ ID NO.:54, and the VL of the antibody or antigen-binding fragment comprises the CDRL1, the CDRL2 and the CDRL3 of the VL amino acid sequence listed in SEQ ID NO.:8; (iii) the VH and VL of the antibody or antigen-binding fragment comprise or consist of the amino acid sequences set forth in SEQ ID NO.: 54 and 8, respectively; and / or (iv) the heavy chain and light chain of the antibody or antigen-binding fragment comprise or consist of the amino acid sequences set forth in SEQ ID NO.: 107 (or SEQ ID NO.: 107 with the C-terminal lysine removed) and 108, respectively, wherein optionally, (1) The influenza infection includes H5N1 IAV, H7N9 IAV, or both; and / or (2) the method comprises administering a single dose of the antibody or antigen-binding fragment to the subject; and / or (3) The method comprises administering 3 mg / kg of the antibody or antigen-binding fragment to the subject, or the method comprises administering 0.9 mg / kg of the antibody or antigen-binding fragment to the subject, or the method comprises administering 0.3 mg / kg of the antibody or antigen-binding fragment to the subject.

84. The method of any one of claims 83, wherein the antibody or antigen-binding fragment comprises a human IgG1 isotype (e.g., comprises an allotype such as IgG1m3 or IgG1m17,1) and comprises M428L and N434S mutations in the Fc, and / or wherein the antibody or antigen-binding fragment comprises two heavy chains and two light chains, each heavy chain comprising or consisting of the amino acid sequence set forth in SEQ ID NO.: 107 (or SEQ ID NO.: 107 with the C-terminal lysine removed), and each The light chain comprises or consists of the amino acid sequence set forth in SEQ ID NO.: 108, and / or wherein the method comprises administering the antibody, the antigen-binding fragment or the composition to the subject by intravenous administration, and / or the composition comprising the antibody or antigen-binding fragment: has an osmolarity of 280 to 315 mOsm / kg; No detectable endotoxin, sensitivity <0.05EU / mg; sterile; pH 7.4; and comprising the antibody or antigen-binding fragment purified by affinity chromatography, and / or the subject: has been infected with H5N1 influenza; is at risk of being infected with H5N1 influenza; has been exposed to H5N1 influenza; has been infected with H7N9 influenza; is at risk of being infected with H7N9 influenza; and / or has been exposed to H7N9 influenza.

85. The method of claim 83 or 84, wherein the treating or preventing comprises prophylaxis.

86. The method of claim 83 or 84, wherein the treatment or prevention comprises post-exposure prophylaxis.

87. A composition comprising an anti-NA antibody or antigen-binding fragment and a pharmaceutically acceptable carrier, excipient or diluent, wherein: (i) the antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 amino acid sequences as set forth in SEQ ID NO.: 55, 4, 5, 9, 10 and 11, respectively; and / or (ii) the antibody or antigen-binding fragment comprises the VH and VL amino acid sequences set forth in SEQ ID NO.: 54 and 8, respectively, wherein optionally, The antibody or antigen-binding fragment comprises a human IgG1 isotype (e.g., comprises an allotype such as IgG1m3 or IgG1m17,1) and comprises M428L and N434S mutations in the Fc, and / or The antibody or antigen-binding fragment comprises the heavy chain amino acid sequence listed in SEQ ID NO.: 107 (or SEQ ID NO.: 107 with the C-terminal lysine removed) and the light chain amino acid sequence listed in SEQ ID NO.: 108, and / or the antibody or antigen-binding fragment of the composition comprises two heavy chains and two light chains, each heavy chain comprising or consisting of the amino acid sequence listed in SEQ ID NO.: 107 (or SEQ ID NO.: 107 with the C-terminal lysine removed), and each The light chain comprises or consists of the amino acid sequence set forth in SEQ ID NO.: 108, and / or The composition comprises the antibody or antigen-binding fragment at a concentration of 3 mg / kg, 0.9 mg / kg or 0.3 mg / kg relative to the body weight (kg) of a subject in need of the composition.

88. The composition of claim 87, wherein the composition: has an osmolarity of 280 to 315 mOsm / kg; has no detectable endotoxin, with a sensitivity of <0.05 EU / mg; is sterile; has a pH of 7.4; and comprises the antibody or antigen-binding fragment purified by affinity chromatography.

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