Retrovirus, and, composition for use in the release of a nucleic acid into a cell.

Description

75 RETROVIRUS, AND, COMPOSITION FOR USE IN THE RELEASE OF A NUCLEIC ACID INTO A CELL (Divided from BR 11 2021 023353 9) RELATED REQUEST

[001] This application claims the benefit under 35 U.S.C. § 119(e) from the filing date of Provisional Application Serial No. U.S. 62 / 851,889, entitled “LIGAND DISCOVERY AND GENE DELIVERY VIA RETROVIRAL SURFACE DISPLAY” and filed May 23, 2019, the entire contents of which are incorporated herein by reference. FUNDAMENTALS

[002] It has been well established that retroviruses (e.g., lentiviruses) can have their natural tropism redirected to targets of interest by pseudotyping a virus to express the envelope protein of a different virus. This is most commonly accomplished by pseudotyping with the VSV glycoprotein, which targets the LDL receptor and thus allows viral entry into a wide range of cells. Recently, groups have shown that if lentiviruses are pseudotyped with paramyxovirus envelope proteins, such as measles virus or nipah virus, and if mutations are created to abolish native tropism, C-terminal fusions to these viruses allow receptor-mediated entry into the target cell of choice. SUMMARY

[003] Here, the inventors have surprisingly demonstrated that a combination of mutations to abolish native function (e.g., tropism) and the overexpression of a second membrane protein allows that second protein to function as the basis for viral entry. These verifications, as described in this paper, enable novel and improved methodologies, for example, for screening cells that are notoriously challenging for specific antigen and function screening (e.g., T cells), and for delivering nucleic acids to target cells in Petition 870260069374, dated 07 / 13 / 2026, page 12 / 131 / 75 a specific form of target.

[004] Some aspects of the description provide compositions of a retrovirus (e.g., a lentivirus) comprising (i) a nucleic acid comprising a nonviral membrane-bound protein comprising a structure: S-ETD-MBD-IRES-R, wherein S encodes a signal sequence, ETD encodes an extracellular tagging domain; MBD encodes a membrane-bound domain, IRES encodes an internal ribosome entry site, and R encodes a reporter; and (ii) a mutated viral envelope protein comprising at least one mutation that diminishes its native function.

[005] Some aspects of the description provide compositions of a retrovirus (e.g., a lentivirus) comprising (i) a CD80 protein domain; and (ii) a mutated viral envelope protein comprising at least one mutation that impairs its native function. The CD80 protein domain may be an extracellular domain. In some embodiments, the extracellular domain of CD80 binds to a receptor on a target cell.

[006] Some aspects of the description provide methods for screening a population of cells, wherein the method comprises (i) providing a retrovirus (e.g., a lentivirus) comprising a viral envelope protein comprising at least one mutation that diminishes its native function, a nonviral membrane-bound protein comprising a membrane-bound domain and an extracellular tagging domain, and a nucleic acid encoding a reporter; (ii) matching the retrovirus to a population of cells; and (iii) classifying the population of cells based on the presence or absence of the reporter. In some embodiments, the retrovirus (e.g., a lentivirus) comprising a nucleic acid comprising a nonviral membrane-bound protein comprising a structure: SETD-MBD-IRES-R, wherein S encodes a signal sequence, ETD encodes an extracellular tagging domain; MBD encodes a membrane-bound domain, IRES encodes an internal ribosome entry site, and R Petition 870260069374, dated 07 / 13 / 2026, page 13 / 131 / 75 encodes a reporter.

[007] In some embodiments, the cells are somatic cells (e.g., antigen-specific cells, e.g., T cells or B cells). In some embodiments, the cells are isolated from an individual (e.g., a human individual). In some embodiments, the cells are isolated from the blood or a tumor of an individual. In some embodiments, the cells are maintained in liquid culture before being combined with the retrovirus.

[008] In some embodiments, the viral envelope protein is a VSV-G envelope protein, a measles virus envelope protein, a nipah virus envelope protein, or a cocal virus G protein. A VSV-G envelope protein may be mutated in one or more of any of H8, K47, Y209, and / or R354. A measles virus envelope protein may be mutated in one or more of any of Y481, R533, S548, and / or F549. A nipah virus envelope protein may be mutated in one or more of any of E501, W504, Q530, and / or E533. A cocal virus G protein may be mutated in K64 and / or R371.

[009] In some embodiments, the nonviral membrane-bound protein comprises a Major Histocompatibility Complex (MHC) protein. In some embodiments, the extracellular labeling domain is a protein (e.g., interleukin-13), a peptide, or an antibody (e.g., anti-CD19 antibody, an anti-TCR antibody, or an anti-CD3 antibody). In some embodiments, the reporter is a fluorescent protein (e.g., green fluorescent protein, yellow fluorescent protein, red fluorescent protein) or an antibiotic resistance marker. In some embodiments, a binder is positioned between the membrane-bound domain and the extracellular labeling domain. A binder can be a rigid binder (e.g., a PDGFR stem or a CD8a stem), a flexible binder (e.g., a PDGFR stem or a CD8a stem), or a flexible binder (e.g., a CD8a stem). Petition 870260069374, dated 13 / 07 / 2026, p. 14 / 131 / 75 example, comprising an amino acid sequence comprising GAPGAS (SEQ ID NO: 5) or GGGGS (SEQ ID NO: 7)), or an oligomerized binder (e.g., an IgG4 linkage or an amino acid sequence that can form a tetrameric coil).

[0010] In some embodiments, the retrovirus is combined with the cell population in (ii) for one minute to seventy-two hours and at a temperature ranging from 4°C to 42°C. In some embodiments, the retrovirus and the cell population are combined in (ii) in the presence of (a) a cell culture medium, optionally RPMI or DMEM cell culture media; (b) a buffered saline solution, optionally phosphate-buffered saline or HEPES-buffered saline; and / or (c) a retroviral transduction enhancer, optionally heparin sulfate, polybrene, protamine sulfate, and / or dextran. In some embodiments, the extracellular labeling domain is able to bind to a cognate protein (e.g., a protein receptor) that is present on the cell surface of a subset of the cell population.In some embodiments, the cell population is washed between (ii) and (iii) (e.g., using phosphate-buffered saline (PBS), for example, to remove retroviruses from the cell population). In some embodiments, cell population sorting is performed using fluorescence-activated cell sorting, single-cell next-generation sequencing, or antibiotic selection.

[0011] In some embodiments, the methods additionally comprise a second retrovirus, wherein the second retrovirus comprises a different extracellular labeling domain and / or a different reporter compared with the first retrovirus.

[0012] Other aspects of the description provide methods for releasing a nucleic acid (e.g., a gene of interest, for example, encoding a protein) into a cell, wherein the method comprises (i) Petition 870260069374, dated 07 / 13 / 2026, page 15 / 131 / 75 to provide a retrovirus comprising nucleic acid, a viral envelope protein comprising at least one mutation that diminishes its native function, and a non-viral membrane-bound protein comprising an extracellular tagging domain capable of binding to a cognate ligand of the cell; and (ii) to place the retrovirus in contact with the cell, thereby releasing the nucleic acid into the cell. In some embodiments, the retrovirus enters or infects the cell during (ii).

[0013] Some aspects of the description provide methods for releasing a nucleic acid into a cell, wherein the method comprises (i) providing a retrovirus comprising the nucleic acid, a viral envelope protein comprising at least one mutation that diminishes its native function and a CD80 protein domain; and (ii) placing the retrovirus in contact with the cell, which thereby releases the nucleic acid into the cell.

[0014] Still other aspects of verification provide methods for detecting an interaction between a retrovirus and a cell, wherein the method comprises: (i) placing a sample comprising the retrovirus and a cell in contact with an antibody, wherein the retrovirus comprises a viral envelope protein comprising at least one mutation that diminishes its native function, a non-viral membrane-bound protein comprising an extracellular labeling domain, and wherein the antibody binds to the extracellular labeling domain of the retrovirus; (ii) optionally removing the unbound antibody from the sample; and (iii) converting the sample into an image to detect whether the antibody-retrovirus complex is bound to the cell.

[0015] In some embodiments, the antibody further comprises a fluorescent tag, optionally, wherein the antibody is covalently linked to a fluorescent tag.In some modalities, the sample image is obtained in (iii) using confocal or fluorescence microscopy.

[0016] Some aspects of the description come from libraries of Petition 870260069374, dated 07 / 13 / 2026, page 16 / 131 / 75 retroviruses, comprising a plurality of unique retroviruses, wherein each unique retrovirus comprises a viral envelope protein comprising at least one mutation that diminishes its native function, a nonviral membrane-bound protein comprising a membrane-bound domain and an extracellular tagging domain (for example, comprising at least 5, at least 10, at least 15, at least 20, or at least 50 amino acids), and a nucleic acid encoding a reporter; and wherein each unique retrovirus comprises a unique and distinct extracellular tagging domain.

[0017] In some embodiments, a library is capable of being screened against an antigen-specific cell population, optionally where the antigen-specific cells are B cells or T cells. A library may comprise at least 102, at least 103, at least 104, at least 105, at least 106, at least 107, at least 108, at least 109, or at least 1010 unique retroviruses. In some embodiments, each different and unique extracellular targeting domain is generated via site-directed mutagenesis.

[0018] Some aspects of the description provide cell populations, wherein a subset of the cell population contains a retrovirus comprising: a viral envelope protein comprising at least one mutation that diminishes its native function, a non-viral membrane-bound protein comprising a membrane-bound domain and an extracellular tagging domain, and a nucleic acid encoding a reporter; In some embodiments, a subset of the cell population (e.g., antigen-specific cells, e.g., B cells or T cells) contains a retrovirus as described herein. In some embodiments, the subset of the cell population contains a retrovirus within each cell of the subset. The subset of the population containing the retrovirus can be isolated and / or sorted from the cells of Petition 870260069374, dated 07 / 13 / 2026, page 17 / 131 / 75 population that does not contain the retrovirus. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 represents an illustrative scheme of a retrovirus of the present invention that interacts with a cognate ligand of a target cell.

[0020] Figure 2 represents an exemplary scheme of a protein comprising a signal sequence (SP), an extracellular marking domain (peptide), a membrane-bound domain (MHC), an internal ribosome entry site (IRES), and a reporter (GFP); and the ability of a retrovirus comprising said protein to interact with a target cell.

[0021] Figures 3A-3B represent graphs that show retroviral entry into a target cell.

[0022] Figure 3A demonstrates that the binding interaction of an extracellular marking domain present in a retrovirus to a cognate ligand of a target cell leads to retrovirus entry and subsequent reporter (GFP) expression.

[0023] Figure 3B demonstrates that contact of a retrovirus with a non-target cell does not lead to entry of the retrovirus.

[0024] Figure 4 represents graphs that show the ability of retroviral entry into target cells at varying affinities between an extracellular labeling domain and its cognate ligand.

[0025] Figures 5A-5B represent graphs showing that T cell signaling is active during retroviral entry or infection.

[0026] Figure 5A demonstrates that the binding interaction of an extracellular marking domain present in a retrovirus to a cognate ligand of a target cell leads to retrovirus entry and activation of T cell signaling.

[0027] Figure 5B demonstrates that contact of a retrovirus with Petition 870260069374, dated 07 / 13 / 2026, page 18 / 131 / 75 a non-target cell does not lead to retrovirus entry or activation of T cell signaling.

[0028] Figure 6 represents an example diagram of a pMHC retroviral library screening methodology.

[0029] Figures 7A-7B represent graphs showing retroviral entry into a target cell.

[0030] Figure 7A demonstrates that the binding interaction of an interleukin-13 (IL-13) protein domain present in a retrovirus to an IL-13 protein receptor of a target cell leads to retrovirus entry and subsequent reporter (GFP) expression.

[0031] Figure 7B demonstrates that contact of a retrovirus comprising an IL-13 protein domain with a non-target cell that does not express an IL-13 protein receptor does not lead to retrovirus entry.

[0032] Figure 8 depicts three exemplary retroviruses, each comprising a different viral envelope protein.

[0033] Figure 9 represents the ability of a retrovirus comprising a Nipah viral envelope protein and an anti-CD19 scFv antibody to infect and enter CD19+ cells.

[0034] Figure 10 represents the ability of a retrovirus comprising a VSV-G viral envelope protein and an anti-CD19 scFv antibody to infect and enter Raji CD19+ cells, while not infecting Jurkat CD19- cells. A retrovirus comprising a wild-type VSV-G viral envelope protein and an anti-CD19 scFv antibody infects both Raji CD19+ cells and Jurkat CD19- cells.

[0035] Figure 11 represents exemplary ligands for use in nucleic acids and proteins comprising extracellular and membrane-bound labeling domains.

[0036] Figure 12 represents graphs showing the effect of short protein ligands (PDGFR; GAPGAS (SEQ ID NO: 5); CAR ECD; Petition 870260069374, dated 07 / 13 / 2026, page 19 / 131 / 75 top, from left to right) and long protein ligands (CD8a; articulation domain; tetrameric coil; bottom, from left to right) in retroviral entry.

[0037] Figure 13 represents graphs showing that retroviruses comprising mutated VSV-G viral envelope proteins activate T cell signaling (right panel) and that retroviruses comprising wild-type VSV-G viral envelope proteins do not activate T cell signaling (left panel), as determined by CD69 expression.

[0038] Figure 14 represents graphs showing that retroviruses with varying affinities between their extracellular marking domains and a cognate T cell ligand are capable of activating T cell signaling.

[0039] Figure 15 represents graphs that show the ability of retroviral entry into target cells at varying affinities, from picomolar to micromolar binding affinities, between an extracellular labeling domain and its cognate ligand.

[0040] Figures 16A-16B represent graphs that demonstrate the ability of retroviral entry into target cells at varying virus concentrations.

[0041] Figure 16A shows the ability of NYESO-1 exhibiting lentivirus to transduce T cells expressing IG4. SL-1 exhibiting lentivirus does not transduce T cells expressing IG4.

[0042] Figure 16B shows the mean fluorescence provided by the interaction between lentivirus-exhibiting NYESO-1 and IG4-expressing T cells.

[0043] Figure 17 represents a graph demonstrating the impact of protein ligand oligomerization on retroviral transduction.

[0044] Figures 18A-18B represent the ability to detect a binding interaction between a retrovirus comprising an antibody. Petition 870260069374, dated 07 / 13 / 2026, page 20 / 131 / 75 scFv anti-CD19 and a target cell comprising CD19 using a fluorescently identified antibody that binds to the retrovirus.

[0045] Figure 18A represents an example connection diagram.

[0046] Figure 18B represents graphs that show the ability of retroviral constructs to interact with a target cell.

[0047] Figure 19 represents the ability of the SL9 lentivirus-exhibiting peptide to transduce 868 TCR-expressing T cells ('868') and the ability of the CMV NLV lentivirus-exhibiting peptide to transduce TCR C7-expressing T cells ('CMV C7').

[0048] Figure 20 depicts the ability of NYESO-1 exhibiting lentivirus to selectively transduce T cells (target cells) expressing a variant of the IG4 T cell receptor (TCR) (binding affinities of ~26 pM or ~32 μM for NYESO-1) relative to cells not expressing an IG4 TCR (off-target) at off-target to target cell ratios as high as 100,000:1.

[0049] Figure 21 represents the ability of lentiviruses displaying various labeling peptides (CMV NLV; EBV; SL9; GL9; NYESO-1) to selectively transduce T cells expressing labeling peptide-specific TCRs (on-target) relative to T cells that do not express labeling peptide-specific TCRs (off-target).

[0050] Figures 22A-22B represent the ability of various lentiviruses (GL9 peptide labeling; NYESO-1 peptide labeling; wild-type VSV) to transduce primary T cells expressing GL9-specific TCRs and T cells expressing an IG4 TCR variant.

[0051] Figure 22A represents the transduction rate of each lentivirus.

[0052] Figure 22B represents the graphs showing FACS data for GL9 virus and NYESO-1 virus. Petition 870260069374, dated 07 / 13 / 2026, page 21 / 131 / 75

[0053] Figure 23 represents graphs showing that primary NYESO-1 reactive cells are specifically infected.

[0054] Figure 24 represents graphs showing that the virus targeting NYESO-1 specifically infects expanded primary cells.

[0055] Figure 25 represents graphs showing the ability of a retrovirus comprising a mutated VSV-G viral envelope protein and a CD80 domain to specifically infect Jurkat T cells, relative to a B cell line.

[0056] Figure 26 depicts the ability of the retrovirus comprising a mutated VSV-G viral envelope protein and an anti-TCR-alpha beta antibody (H57) or an anti-CD3 antibody (C11) to infect TCR-transduced mouse cell lines 58 - / -.

[0057] Figure 27 depicts the ability of a retrovirus comprising a mutated VSV-G viral envelope protein or a mutated cocal viral envelope protein; and an anti-CD19 scFv antibody to infect and enter Raji CD19+ cells, although it does not infect Jurkat CD19- cells. A retrovirus comprising a wild-type VSV-G viral envelope protein and an anti-CD19 scFv antibody infects both Raji CD19+ cells and Jurkat CD19- cells. DETAILED DESCRIPTION OF THE INVENTION

[0058] This document provides new and improved methodologies, for example, for screening cells that are notoriously challenging for specific antigen and function screening (e.g., T cells), and for delivering nucleic acids to target cells in a target-specific form. In some embodiments, systems are described in this document that allow, for example, repertoire-scale analysis of the specificity of the T cell receptor (TCR)-peptide Major Histocompatibility Complex (pMHC), a bottleneck. Petition 870260069374, dated 07 / 13 / 2026, page 22 / 131 / 75 previously intractable, as the methods described above required considerable effort to determine what a single T cell clone can recognize (e.g., as in a typical immune response). In some embodiments, retrovirus-based systems are described in this document that redirect viral tropism as a selection method for molecular interactions and replace the binding functions of wild-type virus surface proteins with those of protein variants of interest, for example, by encoding these variant proteins in the corresponding transfer plasmid used to make the virus, thus ensuring that the resulting virus displays the protein variant on its surface and packaging the corresponding genetic sequence.Therefore, when the virus enters a target cell (for example, one that carries a receptor that binds to the displayed extracellular tagging domain of the protein variant), entry into the cell results in the integration of the genetic sequence of the displayed protein into the target cell's genome.

[0059] Previous approaches to studying T cell specificity required a combination of generated T cell lines, recombinant expression of T cell receptors, and / or individual validation of T cell binding or activity via a candidate antigen-based approach. Each of these elements provided an inherent limitation in the throughput of selected T cells or antigens. For example, yeast display-based methods for deorphanizing T cell receptors alleviated the bottleneck of the number of antigens screened (with the ability to screen >108 ligands), but were still severely limited by the need to express recombinant TCRs. The current strategies of the present invention described herein represent a tremendous advance in the study of T cell specificity and T cell screening, allowing screening of >108 ligands and without the need for recombinant TCR expression. Petition 870260069374, dated 07 / 13 / 2026, page 23 / 131 / 75 RETROVIRUS

[0060] Retroviruses comprising a viral envelope protein comprising at least one mutation that impairs its native function, a nonviral membrane-bound protein comprising a membrane-bound domain and an extracellular marking domain, and a nucleic acid encoding a reporter are described in this document. In some embodiments, a retrovirus comprises a viral envelope protein comprising at least one mutation that impairs its native function, a nonviral membrane-bound protein comprising a membrane-bound domain and an extracellular marking domain.

[0061] The retrovirus described herein comprises one or more elements derived from a retroviral genome (naturally occurring or modified) of a suitable species. Retroviruses include 7 families: alpharetrovirus (avian leukemia virus), betaretrovirus (mouse mammary tumor virus), gammaretrovirus (murine leukemia virus), deltaretrovirus (bovine leukemia virus), epsilonretrovirus (Walleye dermal sarcoma virus), lentivirus (human immunodeficiency virus 1), and foamvirus (human foamvirus). Six additional examples of retroviruses are provided in U.S. Patent No. 7,901,671.

[0062] In some embodiments, a retrovirus is a lentivirus. Lentivirus is a genus of retrovirus that typically gives rise to slow-developing diseases due to its ability to incorporate itself into the host genome. Modified lentiviral genomes are useful as viral vectors for the release of nucleic acids into a host cell. Host cells can be transfected with lentiviral vectors and, optionally, additional vectors to express lentiviral packaging proteins (e.g., VSV-G, Rev, and Gag / Pol) to produce lentiviral particles in the culture medium.

[0063] The constructs of retroviruses and lentiviruses are well known. Petition 870260069374, dated 13 / 07 / 2026, page 24 / 131 / 75 in the art and any suitable retrovirus may be used to construct the retrovirus (or a plurality or library of retroviruses) as described in this document. Non-limiting examples of retrovirus constructs include lentiviral vectors, human immunodeficiency virus (HIV) vector, avian leukemia virus (ALV) vector, murine leukemia virus (MLV) vector, murine mammary tumor virus (MMTV) vector, murine stem cell virus, and human T-cell leukemia virus (HTLV) vector. These retrovirus constructs comprise proviral sequences of the corresponding retrovirus.

[0064] The retrovirus described herein may comprise viral elements, such as those described herein from one or more suitable retroviruses, which are RNA viruses with a positive-sense single-stranded RNA molecule. Retroviruses comprise a reverse transcriptase enzyme and an integrase enzyme. Upon entry into a target cell, retroviruses use their reverse transcriptase to transcribe their RNA molecule into a DNA molecule. Subsequently, the integrase enzyme is used to integrate the DNA molecule into the host cell genome. After integration into the host cell genome, the retrovirus sequence is referred to as a provirus (e.g., proviral sequence or provirus sequence). The retroviral vectors described herein may further comprise additional functional elements, as known in the art, to address safety issues and / or to enhance vector functions, such as packaging efficiency and / or viral concentration.Additional information can be found in US20150316511 and WO2015 / 117027, the relevant descriptions of each of which are incorporated herein by reference for the purposes and subject matter of this document. Additional information for lentiviruses can be found, for example, in WO2019 / 056015, the relevant descriptions of which are incorporated herein by reference. Petition 870260069374, dated 07 / 13 / 2026, p. 25 / 131 / 75 for this specific purpose.

[0065] In some embodiments, lentiviruses are capable of being targeted to specific target cells through pMHC-TCR interaction or any other cell-to-cell protein-protein interaction. In some embodiments, T cells with a known and relevant specificity can be augmented (in the case of cancer or infection) or ablated (in the case of autoimmunity) without affecting other T cells, drastically limiting the risk of off-target effects. In some embodiments, lentiviruses can encode an extracellular domain to target any other molecule expressed on the surface of a target cell. Viral envelope protein

[0066] The retroviruses described herein comprise a viral envelope protein that has at least one mutation that diminishes its native function (e.g., wild-type function of an unmutated viral envelope protein). In some embodiments, a viral envelope protein is any viral envelope protein of any retrovirus (e.g., lentivirus). A viral envelope protein may be a VSV-G envelope protein, a measles virus envelope protein, a nipah virus envelope protein, or a cocal virus G protein. In some embodiments, the native function that is diminished by a mutation of a viral envelope protein is viral tropism (e.g., ability to infect cells, bind to cells, etc.).

[0067] In some embodiments, a viral envelope protein comprising at least one mutation that diminishes its native function is a mutated VSV-G envelope protein. In some embodiments, a viral envelope protein comprising at least one mutation that diminishes its native function is a mutated measles virus envelope protein. In some embodiments, a viral envelope protein comprising at least one mutation that diminishes its native function is a protein of Petition 870260069374, dated 07 / 13 / 2026, page 26 / 131 / 75 mutated Nipah virus envelope. In some embodiments, a viral envelope protein comprising at least one mutation that diminishes its native function is a mutated cocal virus G protein.

[0068] In some embodiments, a mutated VSV-G envelope protein comprises a mutation in H8, K47, Y209, and / or R354. In some embodiments, a mutated VSV-G envelope protein comprises a mutation in H8A, K47A, K47Q, Y209A, R354A, and / or R354Q. In some embodiments, a mutated VSV-G envelope protein is as described in Nikolic et al., “Structural basis for recognition of LDL receptor family members by VSV glycoprotein.” Nature Comm., 2018, 9: 1029, whose relevant descriptions are incorporated herein by reference for this specific purpose.

[0069] In some embodiments, a mutated measles virus envelope protein comprises a mutation in Y481, R533, S548, and / or F549. In some embodiments, a mutated measles virus envelope protein comprises a mutation in Y481A, R533A, S548L, and / or F549S.

[0070] In some embodiments, a mutated Nipah virus envelope protein comprises a mutation in E501, W504, Q530, and / or E533. In some embodiments, a mutated measles virus envelope protein comprises a mutation in E501A, W504A, Q530A, and / or E533A.

[0071] In some embodiments, a mutated cocal virus G protein comprises a mutation in K64 and / or R371. In some embodiments, a mutated cocal virus G protein comprises a mutation in K64Q and / or R371A.

[0072] In some embodiments, the mutated envelope protein is derived from any other enveloped virus, which includes, but is not limited to, baculovirus, herpes simplex virus (HSV), cytomegalovirus (CMV), lymphocytic choriomeningitis virus (LCMV), Epstein-Barr virus (EBV), virus of Petition 870260069374, dated 07 / 13 / 2026, page 27 / 131 / 75 vaccinia, hepatitis A, B or C virus, vaccinia virus, alphavirus, dengue virus, yellow fever virus, Zika virus, influenza virus, hantavirus, Ebola virus, rabies virus, human immunodeficiency virus (HIV), coronavirus and other members of rhabdoviridae.

[0073] In some embodiments, a viral envelope protein comprising at least one mutation comprises 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more mutations. In some embodiments, a viral envelope protein comprising at least one mutation comprises a nucleotide sequence and / or amino acid sequence that is at least 50%, 60%, 70%, 80%, 90%, 95% or 97% identical to a wild-type viral envelope protein. In some embodiments, a viral envelope protein comprising at least one mutation that diminishes its native function retains less than 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20% or 10% of the function of a wild-type viral envelope protein. In some forms, a viral envelope protein that includes at least one mutation lacks all of its native function.In some embodiments, a retrovirus comprising a viral envelope protein that includes at least one mutation that diminishes its native function comprises less than 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, or 10% of the cellular infectivity of a retrovirus comprising a wild-type viral envelope protein. NON-VIRAL MEMBRANE-BOUND PROTEIN

[0074] The retroviruses described in this document comprise a nonviral membrane-bound protein. A nonviral membrane-bound protein may comprise a membrane-bound domain and an extracellular tagging domain. In some embodiments, a nonviral membrane-bound protein is a chimeric protein comprising sequences of at least two different proteins. In some embodiments, a nonviral membrane-bound protein is a full-length or truncated protein. Petition 870260069374, dated 07 / 13 / 2026, page 28 / 131 / 75, which includes the sequence of a single protein.

[0075] A membrane-bound domain is a protein or peptide that has an amino acid sequence that allows the protein or peptide to be wholly or partially incorporated into or associated with the membrane (e.g., envelope) of the retrovirus. In some embodiments, a membrane-bound domain allows for the presentation and release of the extracellular tagging domain to the extracellular environment. In some embodiments, a membrane-bound domain comprises an intracellular domain, a transmembrane domain, and / or an extracellular domain. In some embodiments, a membrane-bound domain comprises both an intracellular and a transmembrane domain. In some embodiments, the membrane-bound domain comprises a Major Histocompatibility Complex (MHC) protein or fragment thereof. An MHC protein may be an MHC Class I or Class II protein.

[0076] In some embodiments, a membrane-bound domain comprises 10-50, 10-100, 25-100, 50-200, 50-150, 100-500, 100-250, 250-500 or any reasonable number of total amino acids.

[0077] In some embodiments, a retrovirus present in a retrovirus library comprises the same membrane-bound domain as some or all of the other retroviruses in the library. In some embodiments, each retrovirus present in a retrovirus library comprises a different membrane-bound domain relative to some or all of the other retroviruses in the library.

[0078] In some embodiments, an extracellular tagging domain is any protein or peptide that has an amino acid sequence and is a binding partner for a target molecule or ligand (e.g., a cognate protein) on a cell surface. When present in the extracellular environment in addition to the interior of the retrovirus, an extracellular tagging domain is capable of binding to a target cell. In some Petition 870260069374, dated 07 / 13 / 2026, page 29 / 131 / 75 embodiments, an extracellular marking domain binds to or targets a cognate protein or ligand (e.g., a protein receptor present on a target cell) that is present on the cell surface of a subset of a cell population. In some embodiments, an extracellular marking domain binds to a cognate protein or ligand that is present on the cell surface of a single T cell or a subset of a T cell population. In some embodiments, a binding interaction between an extracellular marking domain of a retrovirus and a cognate protein or ligand of a cell allows the retrovirus to enter the cell (e.g., an antigen-specific cell, e.g., a T cell).

[0079] In some embodiments, an extracellular labeling domain comprises 10-50, 10-100, 25-100, 50-200, 50-150, 100-500, 100-250, 250-500, or any reasonable number of total amino acids. In some embodiments, an extracellular labeling domain comprises at least 5, at least 10, at least 15, at least 20, or at least 50 amino acids.

[0080] In some embodiments, an extracellular labeling domain is a protein, an antibody, or a peptide. In some embodiments, an antibody is a full-length antibody, an antibody fragment, a nanobody, or a single-chain antibody (scFv). In some embodiments, an extracellular labeling domain is an antibody that binds to a cognate protein of a target cell. In some embodiments, an extracellular labeling domain is an antibody that binds to a B-cell or T-cell antigen. In some embodiments, an extracellular labeling domain is an anti-CD19 antibody (e.g., an antibody that binds to CD19). In some embodiments, an extracellular labeling domain is an antibody that binds to any molecule on the cell surface. In some embodiments, a labeling domain Petition 870260069374, dated 07 / 13 / 2026, p. 30 / 131 / 75 extracellular is an antibody that binds to a lineage marker (e.g., CD3, CD20, integrins, or other receptors), phenotypic markers (PD-1, CD25, CD45, or others). In some embodiments, an extracellular labeling domain is a protein or peptide that binds to a receptor (e.g., a receptor that is present on the surface of a target cell). In some embodiments, an extracellular labeling domain is a protein or peptide that binds to a cytokine receptor (e.g., interleukin-13 (IL-13) receptor). In some embodiments, an extracellular labeling domain is a cytokine (e.g., IL-2, IL-6, IL-12, IL-13). In some embodiments, an extracellular labeling domain is a chemokine ligand (e.g., CXCL9, CXCL10, CXCL11, etc.).In some embodiments, an extracellular labeling domain is a cell receptor, which includes cytokine receptors (e.g., IL-13Ra1, IL-13Ra2, IL-2 receptors, common gamma chain), GPCRs (including chemokine receptors such as CSCR3, CXCR4, etc.), and integrins. In some embodiments, an extracellular labeling domain is a peptide that is displayed by an MHC protein. In some embodiments, the non-viral membrane-bound protein comprises a membrane-bound domain comprising an MHC protein or fragment and an extracellular labeling domain comprising a peptide that is displayed by an MHC protein. In some embodiments, an extracellular domain binds to a T-cell receptor and / or a B-cell receptor.T cell receptors are naturally expressed on the surface of T cells, generally as heterodimeric alpha / beta and gamma / delta integral membrane proteins, where each subunit comprises a short intracellular segment, a single transmembrane alpha-helix, and two extracellular globular Ig superfamily domains. B cell receptors are transmembrane receptor proteins located on the outer surface of B cells.

[0081] In some sports, a marking domain Petition 870260069374, dated 07 / 13 / 2026, page 31 / 131 / 75 extracellular binds to a target cell or cell surface molecule with a binding affinity of 10-9 to 10-8 M, 10-8 to 10-7 M, 10-7 to 10-6 M, 10-6 to 10-5 M, 10-5 to 10-4 M, 10-4 to 10-3 M, or 10-3 to 10-2 M. In some embodiments, an extracellular labeling domain binds to a cognate protein or ligand of a target cell with a binding affinity of 10⁻⁹ to 10⁸ M, 10⁻⁸ to 10⁻⁷ M, 10⁻⁷ to 10⁻⁶ M, 10⁻⁶ to 10⁻⁵ M, 10⁻⁵ to 10⁻⁴ M, 10⁻⁴ to 10⁻³ M, or 10⁻³ to 10⁻² M. In some embodiments, the binding affinity between an extracellular labeling domain and a cognate protein or ligand is in the picomolar to nanomolar range (e.g., between about 10⁻¹² and about 10⁻⁹ M). In some embodiments, the binding affinity between an extracellular labeling domain and a cognate protein or ligand is in the nanomolar to micromolar range (e.g., between about 10⁻⁹ and about 10⁻⁶ M).In some embodiments, the binding affinity between an extracellular labeling domain and a cognate protein or ligand is in the nanomolar to micromolar range (e.g., between about 10⁻⁶ and about 10⁻³ M). In some embodiments, the binding affinity between an extracellular labeling domain and a cognate protein or ligand is in the nanomolar to micromolar range (e.g., between about 10⁻¹² and about 10⁻⁶ M). In some embodiments, the binding affinity between an extracellular labeling domain and a cognate protein or ligand is in the nanomolar to micromolar range (e.g., between about 10⁻⁹ and about 10⁻³ M).

[0082] As used in this document, the term antibody generally refers to a protein that includes at least one immunoglobulin variable domain or immunoglobulin variable domain sequence.For example, an antibody may include a variable heavy chain (H) region (abbreviated in this document as VH) and / or a variable light chain (L) region (abbreviated in this document as VL). In another example, an antibody may include two variable heavy chain (H) regions and / or two variable light chain (L) regions. An antibody may have both... Petition 870260069374, dated 07 / 13 / 2026, page 32 / 131 / 75 structural characteristics of IgA, IgG, IgE, IgD, IgM (as well as subtypes thereof). The Vh and Vl regions can be further subdivided into regions of hypervariability, called complementarity-determining regions (“CDRs”), interspersed with regions that are more conserved, called “structural regions” (“FRs”). Each Vh and / or Vl is typically composed of three CDRs and four FRs arranged from the amino-terminal to the carboxy-terminal in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. The Vh or Vl chain of the antibody may additionally include a constant region of the heavy or light chain, thus forming a heavy or light immunoglobulin chain, respectively. In some embodiments, the antibody is a tetramer of two immunoglobulin heavy chains and two immunoglobulin light chains, in which the immunoglobulin heavy and light chains are linked, for example, by disulfide bonds.In IgGs, the constant region of the heavy chain includes three immunoglobulin domains, CH1, CH2, and CH3.

[0083] In some embodiments, a retrovirus present in a retrovirus library comprises the same extracellular tagging domain as some or all of the other retroviruses in the library. In some embodiments, each retrovirus present in a retrovirus library comprises a different extracellular tagging domain compared to some or all of the other retroviruses in the library.

[0084] In some embodiments, a nonviral membrane-bound protein further comprises a signal sequence (also referred to as a localization sequence signal peptide). In some embodiments, the signal sequence is located at the N- or C-terminal ends of the nonviral membrane-bound protein. A signal sequence functions to translocate the nonviral membrane-bound protein to the membrane (or envelope) of the retrovirus. In some embodiments, a signal sequence is 5-10, 5-15, 10-20, 15-20, 15-30, 20-30, or 25-30 amino acids. In some embodiments, the Petition 870260069374, dated 07 / 13 / 2026, page 33 / 131 / 75. A signal sequence is an Ig Kappa leader sequence (for example, a murine Ig Kappa leader sequence comprising: METDTLLLWVLLLWVPGSTG (SEQ ID NO: 1)) or a B2M signal peptide sequence (for example, a B2M signal peptide sequence comprising: MSRSVALAVLALLSLSGLEA (SEQ ID NO: 2)). In some embodiments, a retrovirus present in a retrovirus library comprises the same signal sequence as some or all other retroviruses in the library. In some embodiments, each retrovirus present in a retrovirus library comprises a different signal sequence relative to some or all other retroviruses in the library.

[0085] In some embodiments, a nucleic acid encoding a nonviral membrane-bound protein further comprises an internal ribosome entry site (IRES). An IRES is an RNA sequence that enables the initiation of translation during protein synthesis. In some embodiments, the IRES is located at or near the C-terminal end. In some embodiments, the IRES is located at the C-terminal relative to the membrane-bound domain and the extracellular tagging domain. In some embodiments, the IRES is a viral IRES. In some embodiments, the IRES is an IRES that is native to the retrovirus. In some embodiments, the IRES is a sequence derived from the encephalomyocarditis virus (EMCV). In some embodiments, a retrovirus present in a retrovirus library comprises the same IRES as some or all of the other retroviruses in the library.In some embodiments, each retrovirus present in a retrovirus library comprises a different IRES in relation to some or all of the other retroviruses in the library.

[0086] In some embodiments, a nonviral membrane-bound protein further comprises a linker positioned between the membrane-bound domain and the extracellular labeling domain. A binder is an amino acid binder and can be a rigid binder, a binder Petition 870260069374, dated 13 / 07 / 2026, p. 34 / 131 / 75 flexible or an oligomerized binder. A rigid binder is an amino acid sequence that lacks flexibility (for example, it may comprise at least one proline). In some embodiments, a rigid binder comprises a platelet-derived growth factor receptor (PDGFR) stem or a CD8a stem. In some embodiments, a PDGFR stem comprises an amino acid sequence comprising AVGQDTQEVIVVPHSLPFK (SEQ ID NO: 3). In some embodiments, a PDGFR stem comprises an amino acid sequence comprising A flexible binder is an amino acid sequence that has many degrees of freedom (e.g., it may comprise a plurality of amino acids with small side chains, e.g., glycine or alanine). In some embodiments, a flexible binder comprises an amino acid sequence comprising GAPGAS (SEQ ID NO: 5). In some embodiments, a flexible binder comprises an amino acid sequence comprising GAPGAS (SEQ ID NO: 6). In some embodiments, a flexible binder comprises an amino acid sequence comprising GAPGAS (SEQ ID NO: 7). In some embodiments, a flexible binder comprises an amino acid sequence comprising GAPGAS (SEQ ID NO: 29) or (G4S)n (SEQ ID NO: 30), where N is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more. An oligomerized binder is an amino acid that can oligomerize into another related amino acid.In some embodiments, an oligomerized binder is an amino acid sequence that can form a dimer, trimer, or tetramer. In some embodiments, an oligomerized binder comprises an IgG4 binding domain (e.g., ASESKYGPPCPPCPAVGQDTQEVIVVPHSLPFK (SEQ ID NO: 8)). In some embodiments, an oligomerized binder comprises a... Petition 870260069374, dated 07 / 13 / 2026, p. 35 / 131 / 75 amino acid sequence that can form a tetrameric coil (e.g., ASGGGGSGELAAIKQELAAIKKELAAIKWELAAIKQGAG (SEQ ID NO: 9)). In some embodiments, an oligomerized binder comprises an amino acid sequence that can form a tetrameric coil (e.g., ASGGGGGSGELAAIKQELAAIKKELAAIKWELAAIKQGAG (SEQ ID NO: 10)). REPORTER

[0087] In some embodiments, the retrovirus described herein may comprise a reporter (e.g., a reporter protein). In some embodiments, the retrovirus described herein may comprise a reporter (e.g., a reporter protein). As used herein, a reporter is generally a protein or gene that can be detected when expressed in a retrovirus and / or target cell. In some embodiments, the presence or absence of a reporter in a target cell or a subset of target cells in a cell population allows the ability to classify cells (e.g., using flow cytometry and / or fluorescence-activated cell sorting).

[0088] In some embodiments, a reporter is a fluorescent protein. A fluorescent protein can be a green fluorescent protein (GFP), a yellow fluorescent protein (YFP), or a red fluorescent protein (RFP). A fluorescent protein can be as described in U.S. Patent No. 7,060,869, entitled “Fluorescent protein sensors for detection of analytes”.

[0089] In some modalities, a reporter is a marker of antibiotic resistance. In some modalities, a marker of antibiotic resistance is a protein or gene that confers an advantage. Petition 870260069374, dated 07 / 13 / 2026, page 36 / 131 / 75 competitive with a target cell containing the marker. In some embodiments, the antibiotic resistance marker comprises a hygromycin resistance protein or gene, a kanamycin resistance protein or gene, an ampicillin resistance protein or gene, a strepthromycin resistance protein or gene, or a neomycin resistance protein or gene. CELLS

[0090] A cell, as described in this document, can be any bacterial, mammalian, or yeast cell. In some embodiments, a cell is a human, mouse, rat, or non-human primate cell. In some embodiments, a cell is a somatic cell or a reproductive cell. In some embodiments, a cell is an epithelial cell, a neural cell, a hormone-secreting cell, an immune cell, a secretory cell, a blood cell, an interstitial cell, or a germ cell. In some embodiments, a cell is an antigen-specific cell (e.g., a cell that binds to a specific antigen). In some embodiments, an antigen-specific cell is an immune cell. In some embodiments, an antigen-specific cell is a B cell or a T cell.In some embodiments, a cell is a target cell (for example, comprising a cognate protein or ligand capable of being targeted by a retrovirus described in this document).

[0091] A cell population, as described in this document, can be any bacterial, mammalian, or yeast cell population. In some embodiments, a cell population is a human, mouse, rat, or non-human primate cell population. In some embodiments, a cell population is a somatic cell population or a reproductive cell population. In some embodiments, a cell population comprises cells Petition 870260069374, dated 07 / 13 / 2026, page 37 / 131 / 75 epithelial cells, neural cells, hormone-secreting cells, immune cells, secretory cells, blood cells, interstitial cells, or germ cells. In some embodiments, a cell is an antigen-specific cell (e.g., a cell that binds to a specific antigen). In some embodiments, a population of antigen-specific cells comprises immune cells. In some embodiments, a population of antigen-specific cells comprises B cells and / or T cells. In some embodiments, a cell population comprises a homogeneous cell population. In some embodiments, a cell population comprises a heterogeneous cell population.

[0092] In some embodiments, a cell population is a population of cells isolated from an individual. An individual may be a human individual (e.g., a human individual suffering from a disease), a mouse individual, a rat individual, or a non-human primate individual. In some embodiments, a cell population is isolated from the blood or tumor of an individual.

[0093] In some embodiments, a cell population has been previously frozen and thawed (e.g., 1, 2, 3, 4, 5 or more freeze / thaw cycles). In some embodiments, a cell population is maintained in liquid culture medium. In some embodiments, a cell population has been passed 1, 2, 3, 4, 5 or more times, using any known method. In some embodiments, a cell population is maintained in liquid culture medium before being combined with a retrovirus or plurality of retroviruses. In some embodiments, a cell population is maintained in liquid culture medium after being combined with a retrovirus or plurality of retroviruses. In some embodiments, a cell population is maintained in liquid culture medium before being combined with a retrovirus or plurality of retroviruses. Petition 870260069374, dated 07 / 13 / 2026, page 38 / 131 / 75

[0094] In some embodiments, a cell population comprises any of the retroviruses described herein. In some embodiments, a subset of a cell population contains any of the retroviruses described herein. In some embodiments, a subset of a cell population contains the retrovirus within each cell of the subset (e.g., within the nucleus of each cell of the subset). In some embodiments, a cell population or a subset thereof expresses a reporter (e.g., a fluorescent protein or an antibiotic resistance marker). In some embodiments, a cell population or a subset thereof (e.g., containing a retrovirus) are isolated and / or classified based on the presence or absence of a reporter.In some embodiments, a subset of a cell population containing retroviruses described in this document is isolated and / or classified based on the presence or absence of a reporter virus from cells in the population that do not contain the retrovirus. In some embodiments, at least 50%, 60%, 70%, 80%, 90%, or 95% of a cell population prior to cell classification contains a retrovirus. In some embodiments, at least 70%, 80%, 90%, 95%, or 100% of a cell population contains a retrovirus after isolation and / or classification based on the presence or absence of a reporter virus. SCREENING METHODS

[0095] This document describes methods for screening a population of cells comprising: (i) providing a retrovirus comprising a viral envelope protein comprising at least one mutation that impairs its native function, a non-viral membrane-bound protein comprising a membrane-bound domain and an extracellular tagging domain, and a nucleic acid encoding a reporter; (ii) matching the retrovirus to a population of cells; and (iii) classifying the Petition 870260069374, dated 07 / 13 / 2026, page 39 / 131 / 75 cell population based on the presence or absence of the reporter. In some embodiments, the retrovirus (i) comprises a nucleic acid comprising a structure: S-ETD-MBD-IRES-R, wherein S encodes a signal sequence, ETD encodes an extracellular tagging domain; MBD encodes a membrane-bound domain, IRES encodes an internal ribosome entry site and R encodes a reporter; and (ii) a mutated viral envelope protein comprising at least one mutation that diminishes its native function.

[0096] As used in this document, the term “combine” (which, in some embodiments, is synonymous with the terms “provide” and “bring into contact”) generally refers to the act of bringing a retrovirus into close physical contact with a cell population, such that the extracellular marking domain of the retrovirus is able to bind to the cognate ligand present on a subset of cells in the population. In some embodiments, the combination of a retrovirus and a cell population occurs when a solution comprising the retrovirus and a solution comprising the cell population are mixed. In some embodiments, the combination of a retrovirus and a cell population occurs when a lyophilized retrovirus and a solution comprising the cell population are mixed.In some embodiments, the combination of a retrovirus and a cell population occurs when a lyophilized retrovirus and a lyophilized cell population are mixed and reconstituted with a solution. In some embodiments, the cells of the population are maintained in cell culture media, in a cell monolayer, and / or are fixed to a tissue culture plate or Petri dish.

[0097] Generally, a retrovirus and a population of cells are combined (e.g., physically combined or brought into contact) for a defined period of time. In some embodiments, a period of time is measured in seconds, minutes, hours, or days. In some Petition 870260069374, dated 07 / 13 / 2026, page 40 / 131 / 75 modalities, the time period is 0-30 seconds, 15-45 seconds, 30-60 seconds, 45-90 seconds, 60-90 seconds, or 60-120 seconds. In some modalities, a retrovirus and a population of cells are combined and brought into contact for 0-30 seconds, 15-45 seconds, 30-60 seconds, 45-90 seconds, 60-90 seconds, or 60-120 seconds. In some modalities, the time period is 1-2 minutes, 1-5 minutes, 1-10 minutes, 2-10 minutes, 5-10 minutes, 5-20 minutes, 10-20 minutes, 25-30 minutes, 25-60 minutes, 30-45 minutes, 30-40 minutes, 40-60 minutes, 50-70 minutes, or 60-120 minutes. In some modalities, a retrovirus and a population of cells are combined and brought into contact for 1-2 minutes, 1-5 minutes, 1-10 minutes, 2-10 minutes, 5-10 minutes, 5-20 minutes, 10-20 minutes, 25-30 minutes, 25-60 minutes, 30-45 minutes, 30-40 minutes, 40-60 minutes, 50-70 minutes, or 60-120 minutes.In some embodiments, a time period is 1-2 hours, 1-5 hours, 1-3 hours, 2-5 hours, 3-6 hours, 3-12 hours, 6-12 hours, 12-18 hours, 12-24 hours, 15-30 hours, 18-24 hours, 24-48 hours, 24-36 hours, or 36-50 hours. In some embodiments, a retrovirus and a population of cells are combined and brought into contact for 1-2 hours, 1-5 hours, 1-3 hours, 2-5 hours, 3-6 hours, 3-12 hours, 6-12 hours, 12-18 hours, 12-24 hours, 15-30 hours, 18-24 hours, 24-48 hours, 24-36 hours, or 36-50 hours. In some modalities, a time period is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 5-15 days. In some modalities, a retrovirus and a population of cells are combined and brought into contact for 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 5-15 days.

[0098] In some embodiments, a population of cells is classified based on the presence or absence of the reporter. In some embodiments, a subset of the cell population that contains the reporter (e.g., expresses the reporter) is classified from the remaining subset of the cell population that does not contain the reporter. In some embodiments, the classification of the cell population is performed using the Petition 870260069374, dated 07 / 13 / 2026, page 41 / 131 / 75 flow cytometry (e.g., fluorescence-activated cell sorting), next-generation genome sequencing (e.g., next-generation single-cell sequencing) or antibiotic selection.

[0099] In some embodiments, the step (ii) conditions that allow the retrovirus to have cell-to-cell interactions with a subset of the cell population comprise combining the retrovirus and the cell population in the presence of defined solutions, compositions, and at specific temperatures. In some embodiments, the retrovirus and the cell population are combined in the presence of a cell culture medium (e.g., RPMI or DMEM cell culture medium). In some embodiments, the retrovirus and the cell population are combined in the presence of a buffered saline solution. In some embodiments, a buffered saline solution is a phosphate-buffered saline solution or a HEPES-buffered saline solution. In some embodiments, a buffered saline solution comprises bovine serum albumin and / or EDTA.In some embodiments, the retrovirus and cell population are combined in the presence of a retroviral transduction enhancer (e.g., heparin sulfate, polybrene, protamine sulfate, or dextran). In some embodiments, the retrovirus and cell population are combined in (ii) a temperature ranging from 4°C to 42°C, 4°C to 8°C, 4°C to 10°C, 8°C to 15°C, 10°C to 20°C, 18°C ​​to 23°C, 20°C to 30°C, 25°C to 35°C, 30°C to 40°C, or 37°C to 42°C.

[00100] In some embodiments, the screening methods described herein further comprise washing the cell population between steps (ii) and (iii) with a washing solution. In some embodiments, a washing solution is any liquid solution that allows the maintenance of healthy cells (e.g., a solution comprising neutral pH, low to moderate levels of ionic strength). In some embodiments, Petition 870260069374, dated 07 / 13 / 2026, page 42 / 131 / 75: Washing the cell population removes excess and / or remaining retroviruses from the cell population. In some embodiments, the cell population is washed using a cell culture medium (e.g., RPMI or DMEM cell culture medium). In some embodiments, the cell population is washed using a buffered saline solution. In some embodiments, a buffered saline solution is a phosphate-buffered saline solution or a HEPES-buffered saline solution. In some embodiments, a buffered saline solution comprises bovine serum albumin and / or EDTA. In some methods, the cell population is washed at temperatures ranging from 4°C to 42°C, 4°C to 8°C, 4°C to 10°C, 8°C to 15°C, 10°C to 20°C, 18°C ​​to 23°C, 20°C to 30°C, 25°C to 35°C, 30°C to 40°C, or 37°C to 42°C.

[00101] In some embodiments, the cell population is maintained in liquid culture before being combined with the retrovirus. In some embodiments, the cell population is maintained in liquid culture after being combined with the retrovirus. In some embodiments, the cell population is maintained in liquid culture during the retrovirus combination step. In some embodiments, the cell population is attached to a cell culture plate or petri dish. In some embodiments, the cell population is maintained in a monolayer, an embryoid body, or any cell aggregate.

[00102] In some embodiments, the screening methods comprise the use of a plurality of retroviruses. In certain embodiments, a plurality of retroviruses comprises at least 102, 103, 104, 105, 106, 107, 108, 109, 1010, 1011, or 1012 unique retroviruses. In certain embodiments, there may be at least 102, 103, 104, 105, 106, 107, 108, 109, 1010, 1011, or 1012 copies of each unique retrovirus present in a plurality of retroviruses.

[00103] In some modalities, screening methods comprise screening a population of cells with at least two Petition 870260069374, dated 13 / 07 / 2026, page 43 / 131 / 75 different and unique retroviruses. In some embodiments, a unique different retrovirus comprises a different extracellular marking domain and / or a different reporter. In some embodiments, the screening methods comprise a first retrovirus and a second retrovirus, wherein the first and second retroviruses comprise different extracellular marking domains and / or different reporters. In some embodiments, the screening methods comprise screening a cell population with 2, 3, 4, 5, 6, 7, 8, 9, 10, 50, 100 or more different retroviruses. In some embodiments, the screening methods comprise screening a cell population with a retrovirus library. In some embodiments, a retrovirus library may comprise at least 102, at least 103, at least 104, at least 105, at least 106, at least 107, at least 108, at least 109, or at least 1010 unique retroviruses.Retrovirus Library.

[00104] Retrovirus libraries are described in this document, wherein a library comprises a plurality of unique retroviruses, wherein each unique retrovirus comprises a viral envelope protein comprising at least one mutation that diminishes its native function, a non-viral membrane-bound protein comprising a membrane-bound domain and an extracellular tagging domain, and a nucleic acid encoding a reporter; and wherein each unique retrovirus comprises a unique and distinct extracellular tagging domain. Cell libraries comprising retroviruses are also described in this document, wherein a library comprises a plurality of unique cells, wherein each unique cell comprises a unique retrovirus.

[00105] In some embodiments, the libraries include retroviral (e.g., lentiviral) libraries encoded by pMHC (peptide / MHC) for use in screening T cell populations. In such libraries, the pMHC displayed on the surface of the virus will allow infection of T cells from a Petition 870260069374, dated 07 / 13 / 2026, page 44 / 131 / 75 specific manner for TCR. Infected T cells can be collected and sequenced, allowing the identification of pMHC ligands that can infect a subset of a T cell population of interest and the ability to simultaneously screen TCR sequences and reactive pMHC ligands. In some embodiments, retroviral pMHC libraries comprise, at a minimum, random transfer vectors containing random pMHC labeling elements. In some embodiments, randomly derived libraries are generated using degenerate oligonucleotide primers. In some embodiments, targeted libraries that are specific for a single set of antigens (e.g., all possible viral or bacterial antigens for a specific target of interest – human immunodeficiency virus, tuberculosis TB, etc., or all possible neoantigens for a given individual) are generated.

[00106] In some embodiments, a library is capable of being screened against an antigen-specific cell population (e.g., B cells or T cells). In some embodiments, a library comprises at least 102, at least 103, at least 104, at least 105, at least 106, at least 107, at least 108, at least 109, or at least 1010 unique retroviruses. In some embodiments, a library comprising unique retroviruses that comprise extracellular targeting domains that are at least 5, at least 10, at least 15, at least 20, or at least 50 amino acids in length. In some embodiments, each different and unique extracellular targeting domain is generated via site-directed mutagenesis.

[00107] Retroviral or cellular libraries can vary in size from hundreds to hundreds of thousands, millions or more of retroviruses or single cells. In some embodiments, the libraries of the description comprise at least 500,000 retroviruses or single cells. The libraries of the invention Petition 870260069374, dated 07 / 13 / 2026, page 45 / 131 / 75 includes retroviral libraries and cellular libraries. A library is a synthetic collection (i.e., isolated, synthetically produced, free of components that are naturally found together in a cell, purified before being placed in the library) of members that have one common element and at least one distinct element. The library comprises one thousand or more (for example, at least: 1,000; 2,000; 3,000; 4,000; 5,000; 10,000; 50,000; 100,000; 500,000; 600,000; 700,000; 800,000; 900,000; 1,000,000; 2,000,000; 3,000,000; 4,000,000; or more) members. The upper limit of the library size is defined by the combination of domains or modules that provide distinction or diversity among the members. For example, a maximum limit might be 4,000,000 members. Thus, in some modalities, the library is highly diverse and includes at least 500,000 distinct members.A highly diverse library can have a diversity of 10⁶ or more. In some embodiments, a retrovirus library is generated using site-directed mutagenesis of a nucleic acid described in this document. In some embodiments, site-directed mutagenesis involves the use of primers and a low-fidelity RNA polymerase to allow random mutagenesis of a common nucleic acid, as described in this document. METHODS OF RELEASING NUCLEIC ACID INTO A CELL

[00108] Methods for delivering a nucleic acid to a cell are described in this document, comprising (i) providing a retrovirus, as described in this document, comprising the nucleic acid, a viral envelope protein comprising at least one mutation that impairs its native function, and a non-viral membrane-bound protein comprising an extracellular tagging domain capable of binding to a cognate ligand of the cell; and (ii) bringing the retrovirus into contact with the cell so that the retrovirus enters and infects the cell. In Petition 870260069374, dated 07 / 13 / 2026, p. 46 / 131 / 75 In some embodiments, the nucleic acid encodes an mRNA molecule, optionally where the mRNA is a gene of interest. In some embodiments, the nucleic acid encodes a double-stranded RNA, an antisense RNA, a microRNA, or any other RNA molecule. In some embodiments, the gene of interest encodes a protein. In some embodiments, the gene of interest encodes a therapeutic protein (e.g., a protein to compensate for an individual's disease condition).

[00109] In some embodiments, the nucleic acid is released into the cell when the retrovirus enters or infects the cell during step (ii). In some embodiments, the nucleic acid release methods described in this document do not require a transfection agent (e.g., a lipophilic transfection agent such as Lipofectin). DETECTION METHODS

[00110] This document describes methods for detecting an interaction between a retrovirus and a cell, comprising: (i) placing a sample comprising the retrovirus and a cell in contact with an antibody, wherein the retrovirus comprises a viral envelope protein comprising at least one mutation that impairs its native function, a non-viral membrane-bound protein comprising an extracellular labeling domain, and wherein the antibody binds to the extracellular labeling domain of the retrovirus; (ii) optionally removing the unbound antibody from the sample; and (iii) converting the sample into an image to detect whether the antibody-retrovirus complex is bound to the cell.

[00111] In some embodiments, the antibody additionally comprises at least one fluorescent marker. In some embodiments, a fluorescent marker is a xanthene derivative (e.g., fluorescein, rhodamine, Oregon green, eosin, and Texas red), a cyanine derivative (e.g., cyanine, indocarbocyanin, Petition 870260069374, dated 07 / 13 / 2026, page 47 / 131 / 75 oxacarbocyanin, thiacarbocyanin and merocyanin), naphthalene derivative (e.g., dansyl and prodane derivatives), coumarin derivative, oxadiazole derivative (e.g., pyridyloxazole, nitrobenzoxadiazole and benzoxadiazole), pyrene derivative (e.g., cascade blue), oxazine derivative (e.g., Nile red, Nile blue, cresyl violet and oxazine 170), acridine derivative (e.g., proflavine, acridine orange and acridine yellow), arylmethine derivative (e.g., auramine, crystal violet and malachite green) or tetrapyrrole derivative (e.g., porphine, phthalocyanine and bilirubin). The fluorescent marker can be non-covalently associated with the antibody or covalently linked to the antibody.

[00112] In some embodiments, the sample image is obtained in step (iii) using confocal or fluorescence microscopy. In some embodiments, detection methods can be performed using standard microscopy settings (e.g., confocal or fluorescence microscopes). In some embodiments, a sample is detected in an ultra-multiplexed format during imaging using standard confocal or epifluorescence microscopy. NUCLEIC ACIDS

[00113] As used in this document, the term “nucleic acids” generally refers to multiple linked nucleotides (i.e., molecules comprising a sugar (e.g., ribose or deoxyribose) linked to an interchangeable organic base, which is either a pyrimidine (e.g., cytosine (C), thymidine (T), or uracil (U)) or a purine (e.g., adenine (A) or guanine (G)). Nucleic acids include DNA, such as D-form DNA and L-form DNA and RNA, as well as various modifications thereof. Modifications include base modifications, sugar modifications, and backbone modifications.

[00114] It should be understood that the nucleic acids used in retroviruses and methods of the invention may be homogeneous or heterogeneous in Petition 870260069374, dated 13 / 07 / 2026, page 48 / 131 / 75 nature. As an example, they may be entirely DNA in nature or may consist of DNA and non-DNA monomers or sequences (e.g., LNA). Thus, any combination of nucleic acid elements can be used. Modification can make the nucleic acid more stable and / or less susceptible to degradation under certain conditions. For example, in some cases, nucleic acids are nuclease resistant. Methods for synthesizing nucleic acids, which include automated nucleic acid synthesis, are also known in the art.

[00115] Nucleic acids may include modifications in their bases. Modified bases include modified cytosines (such as 5-substituted cytosines (e.g., 5-methylcytosine, 5-fluorocytosine, 5-chlorocytosine, 5-bromocytosine, 5-iodocytosine, 5-hydroxycytosine, 5-hydroxymethylcytosine, 5-difluoromethylcytosine, and unsubstituted or substituted 5-alkynylcytosine)), 6-substituted cytosines, N4-substituted cytosines (e.g., N4-ethylcytosine), 5-azacytosine, 2-mercaptocytosine, isocyosine, pseudo-isocytosine, cytosine analogs with condensed ring systems (e.g., N,N'-propylenecytosine or phenoxazine), and uracil and its derivatives (e.g., 5-fluorouracil). 5-bromouracil, 5-bromovinyluracil, 4-thiouracil, 5-hydroxyuracil, 5-propynyluracil), modified guanines, such as 7-deazaguanine, substituted 7-deaza7-guanine (such as 7-deaza7(C2C6)alkynylguanine), substituted 7-deaza8-guanine, hypoxanthine, N2-substituted guanines (e.g.,N2-methylguanine), 5-amino-3-methyl-3H,6H-thiazolo[4,5-d]pyrimidine-2,7-dione, 2,6-diaminopurine, 2-aminopurine, purine, indole, adenine, substituted adenines (e.g., N6-methyladenine, 8-oxo-adenine), 8-substituted guanines (e.g., 8-hydroxyguanine and 8-bromoguanine), and 6-thioguanine. Nucleic acids may comprise universal bases (e.g., 3-nitropyrrole, P-base, 4-methylindole, 5-nitroindole, and K-base) and / or aromatic ring systems (e.g., fluorobenzene, difluorobenzene, benzimidazole, or dichloro). Petition 870260069374, dated 07 / 13 / 2026, page 49 / 131 / 75 benzimidazole, amide of 1-methyl-1H-[1,2,4]triazole-3-carboxylic acid). A specific base pair that can be incorporated into the oligonucleotides of the invention is a non-standard nucleobase pair dZ and dP reported by Yang et al. NAR, 2006, 34(21): 6095-6101. dZ, the pyrimidine analogue, is 6-amino-5-nitro-3-(1'-eD-2'-deoxyribofuranosyl)-2(1H)-pyridone and its Watson-Crick complement dP, the purine analogue, is 2-amino-8-(1'-eD-1'-deoxyribofuranosyl)-imidazo[1,2-a]-1,3,5-triazin-4(8H)-one. AMINO ACID REPLACEMENTS

[00116] In some embodiments, variations of amino acid residues are conservative amino acid substitutions. As used in this document, a “conservative amino acid substitution” refers to an amino acid substitution that does not alter the relative charge or size characteristics of the protein in which the amino acid substitution is made. Variants may be prepared according to methods for altering the polypeptide sequence known to one skilled in the art, as are found in references compiling such methods, for example, Molecular Cloning: A Laboratory Manual, J. Sambrook, et al., eds., Second Edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York, 1989, or Current Protocols in Molecular Biology, FM Ausubel, et al., eds., John Wiley & Sons, Inc., New York.Conservative amino acid substitutions include substitutions made between amino acids within the following groups: (a) M, I, L, V; (b) F, Y, W; (c) K, R, H; (d) A, G; (e) S, T; (f) Q, N; and (g) E, D.

[00117] The “percent identity” of the two amino acid sequences is determined using the algorithm of Karlin and Altschul Proc. Natl. Acad. Sci. USA 87:2264-68, 1990, modified as in Karlin and Altschul Proc. Natl. Acad. Sci. USA 90-5873-77-1993. This algorithm is incorporated into the NBLAST and XBLAST (version 2.0) programs of Altschul, et al. J. Mol. Biol. 215:403-10, 1990. BLAST protein searches can be Petition 870260069374, dated 07 / 13 / 2026, page 50 / 131 / 75 performed with the XBLAST program, score = 50, word length = 3 to obtain amino acid sequences homologous to the protein molecules of interest. Where there are spaces between two sequences, Gapped BLAST can be used as described in Altschul et al., Nucleic Acids Res. 25(17):3389-3402, 1997. When using the BLAST and Gapped BLAST programs, the default parameters of the respective programs (e.g., XBLAST and NBLAST) can be used. EXAMPLES EXAMPLE 1. GENERATION OF RETROVIRUSES THAT TARGET ANTIGEN-SPECIFIC T CELLS

[00118] Targeted lentiviruses were generated by polyethyleneimine (PEI) transfection of HEK293T cells with the following plasmids: an envelope plasmid encoding a mutated VSV-G envelope protein comprising K47Q and R354A mutations, at least one helper plasmid (pRRE, pRev, or psPAX2.1), and a transfer plasmid (FIG. 1). The transfer plasmids used encode a nucleic acid comprising a structure: S-ETD-MBD-IRES-R, wherein S encoded a B2M signal sequence (as provided by SEQ ID NO: 2), ETD encoded a variable extracellular labeling domain (e.g., testicular cancer antigen NYESO-1); MBD encoded a membrane-bound domain (e.g., MHC HLA-A2 domain), IRES encoded an internal ribosome entry site derived from encephalomyocarditis virus (EMCV), and R encoded a green fluorescent protein GFP reporter (FIG. 2).

[00119] The resulting viruses were harvested and purified by standard centrifugation techniques, prior to mixing (using pipette mixing) with T cell lines (e.g., Jurkat T cells) expressing T cell receptors (TCRs) specific for known pMHCs in the presence of hexadimethrin bromide. Petition 870260069374, dated 07 / 13 / 2026, page 51 / 131 / 75

[00120] Mixing HLA-A2-NYESO-1 pMHC display virus with Jurkat T cells expressing an IG4 T cell receptor (TCR) variant (SEQ ID NO: 27) that recognizes the displayed NYESO-1 with a binding affinity of ~26 pM resulted in efficient infection, with 41.9% of T cells expressing the GFP reporter after mixing (FIG. 3A). This result indicated that 41.9% of the T cells in this cell population were infected by the virus. Conversely, mixing HLA-A2-NYESO-1 pMHC display virus with cells that did not express an IG4 TCR resulted in minimal infection, with only 1.1% of T cells expressing the GFP reporter after mixing (FIG. 3B).

[00121] Mixing HLA-A2-NYESO-1 pMHC displaying viruses with T cells expressing different versions of the IG4 TCR (where the different versions of the IG4 TCR exhibit reduced binding to the NYESO1 antigen, compared to the IG4 TCR variant comprising SEQ ID NO: 27) demonstrated that the viruses were able to infect T cells even when the binding affinity between the NYESO-1 antigen and the IG4 TCR dropped to 32 μM (FIG. 4). A binding affinity of 32 μM between the NYESO-1 antigen and an IG4 TCR variant (SEQ ID NO: 24) provided 3.6% transduction; a binding affinity of 84 nM between the NYESO-1 antigen and an IG4 TCR variant (SEQ ID NO: 25) provided 17.6% transduction; and a binding affinity of 5 nM between the NYESO-1 antigen and a TCR IG4 variant (SEQ ID NO: 26) provided 18.1% transduction; when measuring GFP expression.

[00122] T cells expressing 1G4 exhibited T cell activation when transduced / infected with viruses displaying HLA-A2-NYESO-1, as evidenced by the upregulation of CD69 (FIG. 5A). On the other hand, viruses displaying HLA-A2-SL9 do not transduce / infect or activate T cells expressing 1G4 (FIG. 5B). EXAMPLE 2. GENERATION OF RETROVIRUSES THAT TARGET THE Petition 870260069374, dated 07 / 13 / 2026, page 52 / 131 / 75 IL-13 RECEPTOR

[00123] A lentivirus comprising an interleukin-13 (IL-13) extracellular tagging domain was generated, as described in Example 1. The IL-13 extracellular tagging domain consisted of full-length IL-13 protein attached to an IgG4 linkage protein agglutinator and a PDGFR transmembrane domain comprising a truncated cytoplasmic tail (PDGFR transmembrane domain: VVVISAILALVVLTIISLIILIMLWQKKPR (SEQ ID NO: 28)). When the resulting viruses were mixed with Jurkat cells expressing the IL-13Ra1 receptor, efficient transduction was observed, with 85.2% of the cells expressing the GFP reporter after mixing (FIG. 7A). When the same viruses were mixed with cells not expressing any IL-13 receptors, minimal infection was observed (FIG. 7B).

[00124] Lentiviruses expressing additional IL-13 were generated with alternative protein ligands to connect the extracellular labeling domain of IL-13 to the transmembrane domain of PDGFR. Equivalent volumes of all lentiviruses tested were mixed with Jurkat cells bearing the IL13Ra1 receptor and transduction rates were assessed by the GFP reporter (FIG. 12).

[00125] Short and long protein linkers were tested for their ability to enable cell-to-cell interactions between the extracellular labeling domain (IL-13) and the cognate ligand receptor (IL13Ra1). Lentiviruses comprising short linkers were marginally able to infect Jurkat cells, with agglutinant PDGFR (AVGQDTQEVIVVPHSLPFK (SEQ ID NO: 3)) enabling infection of 6.1% of cells; agglutinant GAPGAS (GAPGAS (SEQ ID NO: 5)) enabling infection of 1.0% of cells; agglutinant GAPGAS (GAPGAS (SEQ ID NO: 10)) enabling infection of 1.6% of cells. Lentiviruses comprising short linkers were marginally able to infect Petition 870260069374, dated 07 / 13 / 2026, p. 53 / 131 / 75 Jurkat cells, with PDGFR agglutinant (AVGQDTQEVIVVPHSLPFK (SEQ ID NO: 4)) enabling infection of 88.5% of the cells; GAPGAS agglutinant (GAPGAS (SEQ ID NO: In some embodiments, an oligomerized agglutinant comprises an amino acid sequence that can form a tetrameric coil (e.g., ASGGGGSGELAAIKQELAAIKKELAAIKWELAAIKQGAG (SEQ ID NO: 9)) enabling infection of 38.5% of the cells. EXAMPLE 3. GENERATION OF RETROVIRUSES THAT TARGET CD19

[00126] A lentivirus pseudotyped with an F protein from Nipah virus and a G protein from Nipah virus fused to an anti-CD19 scFv was able to transduce CD19+ Raji B cells (cells expressing CD19), with 14.5% of the cells expressing the GFP reporter after mixing (FIG. 9).

[00127] A lentivirus pseudotyped with VSV-mut (mutated VSV-G) and an anti-CD19 scFv fused to an IgG binding domain, a truncated PDGFR stem, and a PDGFR transmembrane domain was able to transduce Raji B CD19+ cells. Application of 1 pL of VSV-mut lentivirus (200x concentrated) to Raji B CD19+ cells yielded 10.0% infected cells (based on GFP reporter expression); 10 pL of VSV-mut yielded 10.7% infected cells. (FIG. 10). The same VSV-mut lentivirus construct did not transduce / infect Jurkat CD19- cells (cells that do not express CD19), demonstrating that the lentivirus is specific for cells expressing the cognate ligand of its extracellular marking domain (anti-CD19 scFv).

[00128] A lentivirus pseudotyped with VSV-wt (wild-type VSV-G) and an anti-CD19 scFv fused to an IgG binding domain, a truncated PDGFR stem, and a PDGFR transmembrane domain was able to transduce CD19+ Raji B cells and CD19- Jurkat cells. This comparative result demonstrates that the lentivirus comprising a mutated VSV-G Petition 870260069374, dated 07 / 13 / 2026, page 54 / 131 / 75 (in which mutations decrease the native function of the VSV-G protein) is selective to transduce / infect cells that express a cognate ligand targeted by the lentivirus extracellular marking domain. EXAMPLE 4. CAPACITY OF TARGETED LENTIVIRUS TO INDUCE T CELL SIGNALING

[00129] The viruses were evaluated to determine whether infection via TCR labeling resulted in evidence of TCR signaling. Although untargeted VSV-wt viruses efficiently infected T cells, they did not activate T cells, as assessed by CD69 expression levels, compared to controls (FIG. 13, left panel). However, when HLA-A2-NYESO-1 display viruses were used to target Jurkat T cells expressing high-affinity wild-type 1G4 TCR, CD69 upregulation was observed in transduced cells, indicating that TCR signaling occurred during infection (FIG. 13, right panel). These results were replicated by mixing HLA-A2-NYESO-1 display viruses with T cells expressing the low-affinity mutant 1G4 TCR constructs described in Example 1 (FIG. 14). EXAMPLE 5. LENTIVIRAL TRANSDUCTION ACROSS THE TCR IN PHYSIOLOGICAL AFFINITIES

[00130] A population of Jurkat T cells was purified based on IG4 TCR expression before being exposed to viruses exhibiting HLA-A2-NYESO-1. The viruses efficiently transduced the purified populations of Jurkat T cells expressing each of the 1G4 TCR affinity variants, based on GFP reporter expression (FIG. 15). A binding affinity of 32 μM between NYESO-1 antigen and an IG4 TCR variant provided 51.3% transduction; a binding affinity of 84 nM between NYESO-1 antigen and an IG4 TCR variant provided 84.8% transduction; a binding affinity of 5 nM between the Petition 870260069374, dated 07 / 13 / 2026, page 55 / 131 / 75: NYESO-1 antigen and an IG4 TCR variant provided 82.3% transduction; and a binding affinity of 26 nM between NYESO-1 antigen and an IG4 TCR variant provided 73.2% transduction.

[00131] The differences between the different IG4 TCR affinity variants were further investigated by performing a dose response to incubate varying amounts (0.5-10 μL of virus) of the virus exhibiting HLA-A2NYESO-1 with cells. Lentiviruses exhibiting NYESO-1 transduce IG4-expressing T cells, even with high viral load (FIG. 16A). On the other hand, lentiviruses exhibiting SL-1 (negative controls) do not transduce IG4-expressing T cells (SL-1 and IG4 TCR are not cognate binding partners).

[00132] The protein architecture of the membrane-bound NYESO-1 labeling protein was altered to test the ability of oligomerized NYESO-1 display constructs to transduce T cells. NYESO-1 displaying lentiviruses were generated with alternative protein linkers to connect the extracellular NYESO-1 labeling domain to the transmembrane domain (a protein binder comprising the IgG4 linkage (dimer); and an oligomerized binder comprising an amino acid sequence that can form a tetrameric coil (tetramer)). As demonstrated in Figure 17, lentiviruses expressing these alternative architectures were able to transduce T cells expressing the 26 pM and 32 μM IG4 TCR variants. EXAMPLE 6. VIRUS BINDING ASSAY

[00133] The viruses were pseudotyped either with (1) wild-type VSV-G (VSV-G); (2) measles virus F protein and receptor-blind H protein fused to an anti-CD19 scFv and a FLAG identifier (MVaCD19); (3) Nipah virus F protein and receptor-blind G protein fused to an anti-CD19 scFv and a FLAG identifier (NiV-aCD19); or (4) Nipah virus F and receptor-blind G protein with a FLAG identifier but no scFv (killed by NiV). Each of these viruses was mixed with Petition 870260069374, dated 07 / 13 / 2026, page 56 / 131 / 75 Raji CD19+ B cells and subsequently exposed to a fluorescently identified antibody against the FLAG identifier. As demonstrated in Figures 18A-18B, viruses that expressed an anti-CD19 scFv (MV-aCD19 and NiV-aCD19) bound to Raji B cells. Viruses that did not express an anti-CD19 scFv (VSV-G and dead NiV) did not bind to Raji B cells. EXAMPLE 7. SCREENING A RETROVIRUS LIBRARY AGAINST THE T-CELL POPULATION

[00134] A retrovirus library (107-1010 unique retroviruses) comprising a mutated VSV-G envelope protein, a nonviral membrane-bound protein comprising an MHC membrane-bound domain, a variable IL-13 extracellular labeling domain, and a GFP reporter.

[00135] First, a nucleic acid library encoding unique nonviral membrane-bound proteins comprising a membrane-bound MHC domain and a variable IL-13 extracellular labeling domain is prepared using PCR primers that include degenerate codons at positions known to interact with IL-13 receptors and induce random mutagenesis in the IL-13 extracellular labeling domain. The resulting nucleic acid constructs are assembled into viral transfer plasmids with fluorescent reporters by standard molecular cloning techniques. These plasmids (“transfer plasmids”), along with helper plasmids and an envelope plasmid encoding the mutated VSV-G envelope protein (or an equivalent pseudotype), are transfected into retroviruses to generate the retrovirus library.Viruses are purified and mixed with cell populations (e.g., T cell lines, HEK293 cell lines) expressing an IL-13 receptor of interest. The viruses are incubated with the cell populations at an appropriate temperature (e.g., 37°C) for an appropriate period of time (e.g., 1–48 hours). The mixture is... Petition 870260069374, dated 07 / 13 / 2026, page 57 / 131 / 75, performed in standard cell culture medium with hexadimethrin bromide. After 24-48 hours, cells are sorted based on GFP reporter expression. High-expression cells are retained, and the sorting process is repeated as needed. After these rounds of sorting, the retained cells are lysed, and cellular RNA and DNA are isolated for analysis using next-generation sequencing methods to determine which IL-13 variants were able to mediate viral entry. EXAMPLE 8. GENERATION OF ADDITIONAL RETROVIRUSES THAT TARGET ANTIGEN-SPECIFIC T CELLS

[00136] Additional targeted lentiviruses were generated using the protocols described in Example 1.

[00137] As shown in Figure 19, mixing (i) lentivirus comprising a mutated VSV-G envelope protein and pMHC displaying an SL9 peptide and (ii) 868 TCR-expressing T cells demonstrated that the viruses were able to transduce and infect T cells even at low amounts of added virus (~70% transduction at 1 pL of virus). Conversely, mixing these viruses with non-target Jurkat cells led to low levels of transduction (less than 5% up to 10 pL of added virus). A similar experiment, as shown in Figure 19, mixing (i) lentivirus comprising a mutated VSV-G envelope protein and pMHC displaying a cytomegalovirus (CMV) NLV peptide and (ii) TCR-expressing C7 T cells demonstrated that the viruses were able to transduce and infect T cells (~25% transduction at 10 pL of virus). On the other hand, mixing these viruses with off-target Jurkat cells led to low transduction levels (less than 5% up to 10 pL of added virus). EXAMPLE 9. GENERATION OF RETROVIRUSES COMPRISING DISULFIDE-STABILIZED TARGETED PMHCS Petition 870260069374, dated 07 / 13 / 2026, page 58 / 131 / 75

[00138] Additional targeted lentiviruses were generated using the protocols described in Example 1. These additional lentiviruses further comprised a disulfide located within the pMHC in order to stabilize the pMHC structure.

[00139] As shown in Figure 21, mixing (i) lentivirus comprising a mutated VSV-G envelope protein and a disulfide-stabilized pMHC displaying a tagging peptide and (ii) target cells expressing a cognate receptor demonstrated that the targeted viruses were able to transduce and infect target cells. On the other hand, mixing these targeted viruses with non-target cells did not cause transduction or caused very limited transduction (0.1%).

[00140] Specifically, a lentivirus comprising T cells expressing TCR C7 in the target transduced with disulfide-stabilized CMV NLV pMHC at a transduction rate of 21.8%; a lentivirus comprising AS01 cells in the target transduced with disulfide-stabilized EBV pMHC at a transduction rate of 4.8%; a lentivirus comprising T cells expressing TCR 868 in the target transduced with disulfide-stabilized SL9 pMHC at a transduction rate of 22.1%; and a lentivirus comprising T cells expressing TCR IG4 in the target transduced with disulfide-stabilized NYESO-1 pMHC at a transduction rate of 19.0%. EXAMPLE 10. TARGETED VIRUSES TRANSDUCE PRIMARY CELLS

[00141] A primary T cell lineage specific for GL9 (presented by HLA-A2) was specifically and efficiently transduced by viruses that have a mutated VSV-G envelope protein and display GL9 (Figures 22A-22B). Approximately 50% of primary T cells were transduced by these GL9-targeted viruses. On the other hand, these GL9-targeted viruses transduced only 0.3% of T cells expressing TCR IG4. The cells Petition 870260069374, dated 07 / 13 / 2026, page 59 / 131 / 75 T cells expressing TCR IG4 were specifically and efficiently transduced by viruses possessing a mutated VSV-G envelope protein and exhibiting NYESO-1 (55.9% transduction). Furthermore, the targeted virus infects primary cells more efficiently than a wild-type VSV-G virus. These results indicate that targeted viruses can even infect unstimulated primary cells.

[00142] Similarly, a primary NYESO-specific T cell lineage (presented by HLA-A2) was specifically and efficiently transduced by viruses that have a mutated VSV-G envelope protein and display NYESO-1 (Figures 23-24). On the other hand, GL9-targeted viruses were unable to efficiently transduce the NYESO-specific primary T cell lineage. Collectively, these data demonstrate that primary NYESO-1 reactive cells, including expanded primary cells, can be specifically infected by NYESO-targeted viruses. EXAMPLE 11. GENERATION OF A RETROVIRUS THAT INCLUDES THE CD80 DOMAIN

[00143] A pseudotyped virus with a mutated VSV-G envelope protein comprising an extracellular CD80 domain was generated using the protocol described in Example 1. This virus was able to specifically and efficiently infect Jurkat T cells (25.5% transduction) compared to B cells (0.0% transduction) (Figure 25).

[00144] Similarly, a pseudotyped virus with a mutated VSV-G envelope protein comprising a NYESO-1 pMHC and a CD80 extracellular domain was generated using the protocol described in Example 1. This virus was able to specifically and efficiently infect Jurkat T cells (13.5% transduction) compared to B cells (0.2% transduction) (Figure 25). The presence of the CD80 domain allowed the transduction of this virus into Jurkat T cells, as demonstrated by the inability to Petition 870260069374, dated 07 / 13 / 2026, p. 60 / 131 / 75 a pseudotyped virus with a mutated VSV-G envelope protein and comprising only NYESO-1 pMHC to infect these Jurkat T cells (0.9% transduction).

[00145] Collectively, these data show that the presence of CD80 on the surface of the virus mediates specific T cell infection and demonstrates that CD80 can be used to target viruses to T cells. EXAMPLE 12. MURINE ANTI-CD3 ANTIBODY MEDIATES INFECTION OF TCR-TRANSDUCED 58-CELLS

[00146] The display of antibodies that are specific for the murine TCR constant region (H57 antibody) or murine CD3 (2C11 antibody) on the surface of a virus allowed the viruses to infect mouse T cell lines. A virus comprising a mutated VSV-G viral envelope protein and the anti-TCR antibody provided 11.0% transduction of 58α-β- mouse T hybridoma cells; and a virus comprising a mutated VSV-G viral envelope protein and the anti-CD3 antibody provided 12.8% transduction of 58α-β- mouse T hybridoma cells. EXAMPLE 13. GENERATION OF A VIRUS COMPRISING THE G PROTEIN OF THE DEAD COCAL VIRUS

[00147] A lentivirus was pseudotyped with a G protein of cocal virus (dead cocal; amino acid comprising SEQ ID NO: 53) comprising mutations to reduce its infectivity. These mutations, in K64Q and R371A of the cocal virus G protein, were analogous to the mutations used in the dead variant of VSV described in Example 1. The dead cocal virus additionally comprised an displayed scFv anti-CD19 antibody.

[00148] This killed cocal virus was able to transduce Raji CD19+ B cells (8.6% transduction), as shown in FIG. 27, in a manner similar to a lentivirus comprising killed VSV protein and the anti-CD19 scFv antibody shown. Petition 870260069374, dated 07 / 13 / 2026, page 61 / 131 / 75

[00149] These data demonstrate that the viral labeling strategy is highly robust and that any viral envelope protein (e.g., mutated VSV-G, mutated Nipah envelope, mutated measles envelope, mutated cocal viral envelope) that can be mutated to reduce its infectivity can be used effectively. OTHER MODALITIES

[00150] All verified features in this descriptive report can be combined in any combination. Each verified feature in this descriptive report can be replaced by an alternative feature that serves the same, equivalent, or similar purpose. Thus, unless expressly stated otherwise, each described feature is only an example of a generic series of equivalent or similar features.

[00151] From the above description, one skilled in the art can easily determine the essential features of the present invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various uses and conditions. Thus, other embodiments are also within the claims. EQUIVALENTS

[00152] Although several inventive embodiments have been described and illustrated in this document, those skilled in the art will readily imagine a variety of other means and / or structures to perform the function and / or obtain the results and / or one or more of the advantages described in this document, and each of these variations and / or modifications is considered to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily recognize that all parameters, dimensions, materials, and configurations described in this document are intended to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend on the specific application or applications for which the inventive teachings are intended. Petition 870260069374, dated 07 / 13 / 2026, pp. 62 / 131 / 75 are used. Those skilled in the art will recognize, or will be able to verify using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It should therefore be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended and equivalent claims, the inventive embodiments may be practiced in a manner other than that specifically described and claimed. The inventive embodiments of the present description are directed to each individual feature, system, article, material, kit and / or method described herein.Furthermore, any combination of two or more resources, systems, articles, materials, kits and / or methods, provided that these resources, systems, articles, materials, kits and / or methods are not mutually inconsistent, is included within the inventive scope of the present description.

[00153] All definitions, as defined and used in this document, should be understood as controlling dictionary definitions, definitions in documents incorporated by reference and / or common meanings of the defined terms.

[00154] All references, patents and patent applications described in this document are incorporated by reference with respect to the subject matter for which each is cited, which in some cases may encompass the entire document.

[00155] The indefinite articles “a” and “an,” as used in this document in the descriptive report and claims, unless clearly stated otherwise, should be understood to mean “at least one.”

[00156] The phrase “and / or”, as used in this document in the descriptive report and claims, should be understood as meaning “one or both” of the elements thus combined, that is, elements that are Petition 870260069374, dated 07 / 13 / 2026, p. 63 / 131 / 75 present conjuncturally in some cases and disjuncturally in others. Several elements listed with “and / or” should be interpreted in the same way, that is, “one or more” of the elements thus joined. Other elements may optionally be present in addition to the elements specifically identified by the “and / or” clause, whether or not they are related to those specifically identified elements. Thus, as a non-limiting example, a reference to “A and / or B”, when used in conjunction with open language, such as “which includes” may refer, in one way, only to A (optionally including elements other than B); in another way, to B only (optionally including elements other than A); in yet another way, to A and B (optionally including other elements); etc.

[00157] As used in this document in the descriptive report and claims, “or” should be understood as having the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” should be interpreted as being inclusive, i.e., including at least one, but also including more than one, of a number or list of elements, and optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of” or “exactly one of”, or, when used in claims, “consisting of”, refer to the inclusion of exactly one element of a number or list of elements.In general, the term “or”, as used in this document, should only be interpreted as indicating exclusive alternatives (i.e., “either one or the other, but not both”) when preceded by terms of exclusivity, such as “any one”, “one of”, “only one of” or “exactly one of”, “consisting essentially of”, when used in the claims, should have its common meaning as used in the field of patent law.

[00158] As used in this document in the descriptive report and Petition 870260069374, dated 13 / 07 / 2026, p. 64 / 131 / 75, in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood as meaning at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each of the elements specifically listed in the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows for elements to be optionally present in addition to the elements specifically identified in the list of elements to which the phrase “at least one” refers, whether or not they are related to those specifically identified elements.Thus, as a non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B" or, equivalently, "at least one of A and / or B") may refer, in one embodiment, to at least one, optionally including more than one, A, without B present (and optionally including other entities besides B); in another embodiment, to at least one, optionally including more than one, B, without A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A and at least one, optionally including more than one, B (and optionally including other elements); etc.

[00159] It should also be understood that, unless clearly stated otherwise, in any methods claimed in this document that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited. SEQUENCES >Kappa leader sequence, amino acid (SEQ ID NO: 1): METDTLLLWVLLLWVPGSTG >B2M signal peptide sequence, amino acid (SEQ ID Petition 870260069374, dated 07 / 13 / 2026, pp. 65 / 131 / 75 NO: 2): MSRSVALAVLALLSLSGLEA >Short PDGFR stem, amino acid (SEQ ID NO: 3): AVGQDTQEVIVVPHSLPFK >Long PDGFR stem, amino acid (SEQ ID NO: 4): ASAKPTTTPAPRPPTPAPTIASQPLSLRPEAARPAAGGAVHTRGLDFAK >Short flexible linker, amino acid (SEQ ID NO: 5): GAPGAS >Long flexible linker, amino acid (SEQ ID NO: 6): GAPGSGGGGSGGGGSAS >Short flexible linker, amino acid (SEQ ID NO: 7): GGGGS >IgG4 binding domain, amino acid (SEQ ID NO: 8): ASESKYGPPCPPCPAVGQDTQEVIVVPHSLPFK >Tetrameric coil, amino acid (SEQ ID NO: 9): ASGGGGSGELAAIKQELAAIKKELAAIKWELAAIKQGAG >Dimeric coiled spiral, amino acid (SEQ ID NO: 10): ASESKYGPPCPPCP > Wild-type VSV-G envelope protein (with leader sequence), DNA sequence (SEQ ID NO: 11): atgaagtgccttttgtacttagcctttttattcattggggtgaattgcaagttcaccatagttttt ccacacaaccaaaaaggaaactggaaaaatgttccttctaattaccattattgcccgtcaagctcagatttaaatt ggcataatgacttaataggcacagccatacaagtcaaaatgcccaagagtcacaaggctattcaagcagacgg ttggatgtgtcatgcttccaaatgggtcactacttgtgatttccgctggtatggaccgaagtatataacacagtcca tccgatccttcactccatctgtagaacaatgcaaggaaagcattgaacaaacgaaacaaggaacttggctgaat ccaggcttccctcctcaaagttgtggatatgcaactgtgacggatgccgaagcagtgattgtccaggtgactcct caccatgtgctggttgatgaatacacaggagaatgggttgattcacagttcatcaacggaaaatgcagcaattac atatgccccactgtccataactctacaacctggcattctgactataaggtcaaagggctatgtgattctaacctcat ttccatggacatcaccttcttctcagaggacggagagctatcatccctgggaaaggagggcacagggttcaga agtaactactttgcttatgaaactggaggcaaggcctgcaaaatgcaatactgcaagcattggggagtcagact Petition 870260069374, of 13 / 07 / 2026, p. 66 / 131 / 75 cccatcaggtgtctggttcgagatggctgataaggatctctttgctgcagccagattccctgaatgcccagaagg gtcaagtatctctctccatctcagacctcagtggatgtaagtctaattcaggacgttgagaggatcttggattatt ccctctgccaagaaacctggagcaaaatcagagcgggtcttctctccagtggatctcagctatcttgctc ctaaaaacccaggaaccggtcttgctttcaccataatcaatggtaccctaaaatactttgagaccagatacatca gagtcgatattgctgctccaatcctcaagaatggtcggaatgatgatgatgaactaccacagaaagggaactg tgggatgactgggcaccatatgaagacgtggaaattgacccaatggagttctgaggaccagttcaggatata agttcctttatacatgatgacatgtatgttggactccgatctctctctcttagctcaggcgacgagtt atcctcacattcaagacgctgcttcgcaacttcctgatgatgagagtttattttggtgatactgggctatccaaaa atccaatcgagcttgtagaaggttggttcagtagttggaaaagctctattgcctcttttttcttcatagggttaatc > Wild-type VSV-G envelope protein (with leader sequence), amino acid sequence (SEQ2): ID NO: 12 MKCLLYLAFLFIGVNCKFTIVFPHNQKGNWKNVPSNYH YCPSSSSDLNWHNDLIGTAIQVKMPKSHKAIQADGWMCHASKWVTTC DFRWYGPKYITQSIRSFTPSVEQCKESIEQTKQGTWLNPGFPPQSCGY ATVTDAEAVIVQVTPHHVLVDEYTGEWVDSQFINGKCSNYICPTVHN STTWHSDYKVKGLCDSNLISMDITFFSEDGELSSLGKEGTGFRSNYFA YETGGKACKMQYCKHWGVRLPSGVWFEMADKDLFAAARFPECPEG SSISAPSQTSVDVSLIQDVERILDYSLCQETWSKIRAGLPISPVDLSYLA PKNPGTGPAFTIINGTLKYFETRYIRVDIAAPILSRMVGMISGTTTEREL WDDWAPYEDVEIGPNGVLRTSSGYKFPLYMIGHGMLDSDLHLSSKA QVFEHPHIQDAASQLPDDESLFFGDTGLSKNPIELVEGWFSSWKSSIAS FFFIIGLIIGLFLVLRVGIHLCIKLKHTKKRQIYTDIEMNRLGK > Wild-type VSV-G envelope protein, amino acid sequence (SEQ ID NO: 13): KFTIVFPHNQKGNWKNVPSNYHYCPSSSDLNWHNDLIG TAIQVKMPKSHKAIQADGWMCHASKWVTTCDFRWYGPKYITQSIRS FTPSVEQCKESIEQTKQGTWLNPGFPPQSCGYATVTDAEAVIVQVTPH Petition 870260069374, dated 07 / 13 / 2026, page 67 / 131 / 75 HVLVDEYTGEWVDSQFINGKCSNYICPTVHNSTTWHSDYKVKGLCD SNLISMDITFFSEDGELSSLGKEGTGFRSNYFAYETGGKACKMQYCKH WGVRLPSGVWFEMADKDLFAAARFPECPEGSSISAPSQTSVDVSLIQD VERILDYSLCQETWSKIRAGLPISPVDLSYLAPKNPGTGPAFTIINGTLK YFETRYIRVDIAAPILSRMVGMISGTTTERELWDDWAPYEDVEIGPNG VLRTSSGYKFPLYMIGHGMLDSDLHLSSKAQVFEHPHIQDAASQLPD DESLFFGDTGLSKNPIELVEGWFSSWKSSIASFFFIIGLIIGLFLVLRVGI HLCIKLKHTKKRQIYTDIEMNRLGK > VSV-G envelope protein (with leader sequence), DNA sequence (SEQ ID NO: 14): atgaagtgccttttgtacttagcctttttattcattggggtgaattgcaagttcaccatagttttt ccacacaaccaaaaaggaaactggaaaaatgttccttctaattaccattattgcccgtcaagctcagatttaaatt ggcataatgacttaataggcacagccttacaagtcaaaatgccccagagtcacaaggctattcaagcagacgg ttggatgtgtcatgcttccaaatgggtcactacttgtgatttccgctggtatggaccgaagtatataacacagtcca tccgatccttcactccatctgtagaacaatgcaaggaaagcattgaacaaacgaaacaaggaacttggctgaat ccaggcttccctcctcaaagttgtggatatgcaactgtgacggatgccgaagcagtgattgtccaggtgactcct caccatgtgctggttgatgaatacacaggagaatgggttgattcacagttcatcaacggaaaatgcagcaattac atatgccccactgtccataactctacaacctggcattctgactataaggtcaaagggctatgtgattctaacctcat ttccatggacatcaccttcttctcagaggacggagagctatcatccctgggaaaggagggcacagggttcaga agtaactactttgcttatgaaactggaggcaaggcctgcaaaatgcaatactgcaagcattggggagtcagact cccatcaggtgtctggttcgagatggctgataaggatctctttgctgcagccagattccctgaatgcccagaagg gtcaagtatctctgctccatctcagacctcagtggatgtaagtctaattcaggacgttgagaggatcttggattatt ccctctgccaagaaacctggagcaaaatcagagcgggtcttccaatctctccagtggatctcagctatcttgctcctaaaaacccaggaaccggtcctgctttcaccataatcaatggtaccctaaatactttgagaccagatacatca gagtcgatattgctgctccaatcctcaagaatggtcggaatgatcagtggaactaccacagaagccgaactg tgggatgactgggcaccatatgagacgtggaattggaactcgcgacgacagattgacatta agtttcctttatacatgattggacatggtatgttggactccgatcttcatcttagctcaaagctcaggtgttcgaac atcctcacattcaagacgctgcttcgcaacttcctgatgagagtttattttggtgatactgggctatccaaaa atccaatcgagcttgtagaaggttggttcagtagttggaaaagctctattgcctctttttcttatcatagggttaatc Petition 870260069374, of 13 / 07 / 2026, p. 68 / 131 / 75 attggactattcttggttctccgagttggtatccatctttgcattaaattaaagcacaccaagaaaagacagatttat acagacatagagatgaaccgacttggaaagtaa > VSV-G envelope protein (com sequência líder), amino acid sequence (SEQ5: NO): NO MKCLLYLAFLFIGVNCKFTIVFPHNQKGNWKNVPSNYH YCPSSSDLNWHNDLIGTALQVKMPQSHKAIQADGWMCHASKWVTT CDFRWYGPKYITQSIRSFTPSVEQCKESIEQTKQGTWLNPGFPPQSCGY ATVTDAEAVIVQVTPHHVLVDEYTGEWVDSQFINGKCSNYICPTVHN STTWHSDYKVKGLCDSNLISMDITFFSEDGELSSLGKEGTGFRSNYFA YETGGKACKMQYCKHWGVRLPSGVWFEMADKDLFAAARFPECPEG SSISAPSQTSVDVSLIQDVERILDYSLCQETWSKIRAGLPISPVDLSYLA PKNPGTGPAFTIINGTLKYFETRYIRVDIAAPILSRMVGMISGTTTEAEL WDDWAPYEDVEIGPNGVLRTSSGYKFPLYMIGHGMLDSDLHLSSKA QVFEHPHIQDAASQLPDDESLFFGDTGLSKNPIELVEGWFSSWKSSIAS FFFIIGLIIGLFLVLRVGIHLCIKLKHTKKRQIYTDIEMNRLGK > Proteína de envelope VSV-G I41L / K47Q / R354A, sequência de aminoácido (SEQ ID NO: 16): KFTIVFPHNQKGNWKNVPSNYHYCPSSSDLNWHNDLIG TALQVKMPQSHKAIQADGWMCHASKWVTTCDFRWYGPKYITQSIRS FTPSVEQCKESIEQTKQGTWLNPGFPPQSCGYATVTDAEAVIVQVTPH HVLVDEYTGEWVDSQFINGKCSNYICPTVHNSTTWHSDYKVKGLCD SNLISMDITFFSEDGELSSLGKEGTGFRSNYFAYETGGKACKMQYCKH WGVRLPSGVWFEMADKDLFAAARFPECPEGSSISAPSQTSVDVSLIQD VERILDYSLCQETWSKIRAGLPISPVDLSYLAPKNPGTGPAFTIINGTLK YFETRYIRVDIAAPILSRMVGMISGTTTEAELWDDWAPYEDVEIGPNG VLRTSSGYKFPLYMIGHGMLDSDLHLSSKAQVFEHPHIQDAASQLPD DESLFFGDTGLSKNPIELVEGWFSSWKSSIASFFFIIGLIIGLFLVLRVGI HLCIKLKHTKKRQIYTDIEMNRLGK > VSV-G envelope protein K47Q / R354A, sequence of Petition 870260069374, dated 07 / 13 / 2026, page 69 / 131 / 75 amino acid (SEQ ID NO: 17): KFTIVFPHNQKGNWKNVPSNYHYCPSSDLNWHNDLIG TAIQVKMPQSHKAIQADGWMCHASKWVTTCDFRWYGPKYITQSIRS FTPSVEQCKESIEQTKQGTWLNPGFPPQSCGYATVTDAEAVIVQVTPH HVLVDEYTGEWVDSQFINGKCSNYICPTVHNSTTWHSDYKVKGLCD SNLISMDITFFSEDGELSSLGKEGTGFRSNYFAYETGGKACKMQYCKH WGVRLPSGVWFEMADKDLFAAARFPECPEGSSISAPSQTSVDVSLIQD VERILDYSLCQETWSKIRAGLPISPVDLSYLAPKNPGTGPAFTIINGTLK YFETRYIRVDIAAPILSRMVGMISGTTTEAELWDDWAPYEDVEIGPNG VLRTSSGYKFPLYMIGHGMLDSDLHLSSKAQVFEHPHIQDAASQLPD DESLFFGDTGLSKNPIELVEGWFSSWKSSIASFFFIIGLIIGLFLVLRVGI HLCIKLKHTKKRQIYTDIEMNRLGK > Exemplary wild-type measles envelope protein (with leader sequence), DNA sequence (SEQ ID NO: 18): ATGGGCAGCCGGATCGTGATCAACCGGGAGCACCTG ATGATCGACCGGCCCTACGTGCTGCTGGCCGTGCTGTTCGTGATGT TCCTGAGCCTGATCGGCTTGCTAGCCATTGCTGGAATCCGGCTGCA CAGAGCCGCCATCTACACCGCCGAGATCCACAAGAGCCTGAGCAC CAACCTGGACGTGACCAACAGCATCGAGCATCAGGTCAAGGACGT GCTGACCCCCCTGTTTAAGATCATCGGCGACGAAGTGGGCCTGCG GACCCCCCAGAGATTCACCGACCTGGTCAAGTTCATCAGCGACAA GATCAAGTTCCTGAACCCCGACCGGGAGTACGACTTCCGGGACCT GACCTGGTGCATCAACCCCCCCGAGCGGATCAAGCTGGACTACGA CCAGTACTGCGCCGATGTGGCCGCCGAGGAACTGATGAATGCATT GGTGAACTCAACTCTACTGGAGACCAGAACAACCAATCAGTTCCT AGCTGTCTCAAAGGGAAACTGCTCAGGGCCCACTACAATCAGAGG TCAATTCTCAAACATGTCGCTGTCCCTGTTAGACTTGTATTTAGGTC GAGGTTACAATGTGTCATCTATAGTCACTATGACATCCCAGGGAAT GTATGGGGGAACTTACCTAGTGGAAAAGCCTAATCTGAGCAGCAA Petição 870260069374, de 13 / 07 / 2026, pág. 70 / 131 / 75 AAGGTCAGAGTTGTCACAACTGAGCATGTACCGAGTGTTTGAAGT AGGTGTTATCAGAAATCCGGGTTTGGGGGCTCCGGTGTTCCATATG ACAAACTATCTTGAGCAACCAGTCAGTAATGATCTCAGCAACTGT ATGGTGGCTTTGGGGGAGCTCAAACTCGCAGCCCTTTGTCACGGG GAAGATTCTATCACAATTCCCTATCAGGGATCAGGGAAAGGTGTC AGCTTCCAGCTCGTCAAGCTAGGTGTCTGGAAATCCCCAACCGAC ATGCAATCCTGGGTCCCCTTATCAACGGATGATCCAGTGATAGACA GGCTTTACCTCTCATCTCACAGAGGTGTTATCGCTGACAACCAAGC AAAATGGGCTGTCCCGACAACACGAACAGATGACAAGTTGCGAAT GGAGACATGCTTCCAACAGGCGTGTAAGGGTAAAATCCAAGCACT CTGCGAGAATCCCGAGTGGGCACCATTGAAGGATAACAGGATTCC TTCATACGGGGTCTTGTCTGTTGATCTGAGTCTGACAGTTGAGCTT AAAATCAAAATTGCTTCGGGATTCGGGCCATTGATCACACACGGTT CAGGGATGGACCTATACAAATCCAACCACAACAATGTGTATTGGC TGACTATCCCGCCAATGAAGAACCTAGCCTTAGGTGTAATCAACA CATTGGAGTGGATACCGAGATTCAAGGTTAGTCCCtatCTCTTCAcaG TCCCAATTAAGGAAGCAGGCGGAGACTGCCATGCCCCAACATACC TACCTGCGGAGGTGGATGGTGATGTCAAACTCAGTTCCAATCTGGT GATTCTACCTGGTCAAGATCTCCAATATGTTTTGGCAACCTACGAT ACTTCCcgGGTTGAACATGCTGTGGTTTATTACGTTTACAGCCCAAG CCGCTCATTTTCTTACTTTTATCCTTTTAGGTTGCCTATAAAGGGGGTCCCCATCGAATTACAAGTGGAATGCTTCACATGGGACCAAAAAC TCTGGTGCCGTCACTTCTGTGTGCTTGCGGACTCAGAATCTGGTGG ACATATCACTCACTCTGGGATGGTGGGCATGGGAGTCAGCTGCAC AGTCACCCGGGAAGATGGAACCAATGACTACAAAGACGATGACG ACAAGTGA > Exemplary wild-type measles envelope protein, amino acid sequence (SEQ ID NO: 19): MGSRIVINREHLMIDRPYVLLAVLFVMFLSLIGLLAIAGI Petition 870260069374, dated 07 / 13 / 2026, p. 71 / 131 / 75 RLHRAAIYTAEIHKSLSTNLDVTNSIEHQVKDVLTPLFKIIGDEVGLRT PQRFTDLVKFISDKIKFLNPDREYDFRDLTWCINPPERIKLDYDQYCAD VAAEELMNALVNSTLLETRTTNQFLAVSKGNCSGPTTIRGQFSNMSLS LLDLYLGRGYNVSIVTMTSQGMYGGTYLVEKPNLSSKRSELSQLSM YRVFEVGVIRNPGLGAPVFHMTNYLEQPVSNDLSNCMVALGELKLA ALCHGEDSITIPYQGSGKGVSFQLVKLGVWKSPTDMQSWVPLSTDDP VIDRLYLSSHRGVIADNQAKWAVPTTRTDDKLRMETCFQQACKGKIQ ALCENPEWAPLKDNRIPSYGVLSVDLSLTVELKIKIASGFGPLITHGSG MDLYKSNHNNVYWLTIPPMKNLALGVINTLEWIPRFKVSPYLFTVPIK EAGGDCHAPTYLPAEVDGDVKLSSNLVILPGQDLQYVLATYDTSRVE HAVVYYVYSPSRSFSYFYPFRLPIKGVPIELQVECFTWDQKLWCRHFC VLADSESGGHITHSGMVGMGVSCTVTREDGTNDYKDDDDK > Proteína de envelope de sarampo mutante exemplificadora, sequencia de DNA (SEQ ID NO: 20): ATGGGCAGCCGGATCGTGATCAACCGGGAGCACCTG ATGATCGACCGGCCCTACGTGCTGCTGGCCGTGCTGTTCGTGATGT TCCTGAGCCTGATCGGCTTGCTAGCCATTGCTGGAATCCGGCTGCA CAGAGCCGCCATCTACACCGCCGAGATCCACAAGAGCCTGAGCAC CAACCTGGACGTGACCAACAGCATCGAGCATCAGGTCAAGGACGT GCTGACCCCCCTGTTTAAGATCATCGGCGACGAAGTGGGCCTGCG GACCCCCCAGAGATTCACCGACCTGGTCAAGTTCATCAGCGACAA GATCAAGTTCCTGAACCCCGACCGGGAGTACGACTTCCGGGACCT GACCTGGTGCATCAACCCCCCCGAGCGGATCAAGCTGGACTACGA CCAGTACTGCGCCGATGTGGCCGCCGAGGAACTGATGAATGCATT GGTGAACTCAACTCTACTGGAGACCAGAACAACCAATCAGTTCCT AGCTGTCTCAAAGGGAAACTGCTCAGGGCCCACTACAATCAGAGG TCAATTCTCAAACATGTCGCTGTCCCTGTTAGACTTGTATTTAGGTC GAGGTTACAATGTGTCATCTATAGTCACTATGACATCCCAGGGAAT GTATGGGGGAACTTACCTAGTGGAAAAGCCTAATCTGAGCAGCAA Petição 870260069374, de 13 / 07 / 2026, pág. 72 / 131 / 75 AAGGTCAGAGTTGTCACAACTGAGCATGTACCGAGTGTTTGAAGT AGGTGTTATCAGAAATCCGGGTTTGGGGGCTCCGGTGTTCCATATG ACAAACTATCTTGAGCAACCAGTCAGTAATGATCTCAGCAACTGT ATGGTGGCTTTGGGGGAGCTCAAACTCGCAGCCCTTTGTCACGGG GAAGATTCTATCACAATTCCCTATCAGGGATCAGGGAAAGGTGTC AGCTTCCAGCTCGTCAAGCTAGGTGTCTGGAAATCCCCAACCGAC ATGCAATCCTGGGTCCCCTTATCAACGGATGATCCAGTGATAGACA GGCTTTACCTCTCATCTCACAGAGGTGTTATCGCTGACAACCAAGC AAAATGGGCTGTCCCGACAACACGAACAGATGACAAGTTGCGAAT GGAGACATGCTTCCAACAGGCGTGTAAGGGTAAAATCCAAGCACT CTGCGAGAATCCCGAGTGGGCACCATTGAAGGATAACAGGATTCC TTCATACGGGGTCTTGTCTGTTGATCTGAGTCTGACAGTTGAGCTT AAAATCAAAATTGCTTCGGGATTCGGGCCATTGATCACACACGGTT CAGGGATGGACCTATACAAATCCAACCACAACAATGTGTATTGGC TGACTATCCCGCCAATGAAGAACCTAGCCTTAGGTGTAATCAACA CATTGGAGTGGATACCGAGATTCAAGGTTAGTCCCGCGCTCTTCAA TGTCCCAATTAAGGAAGCAGGCGGAGACTGCCATGCCCCAACATA CCTACCTGCGGAGGTGGATGGTGATGTCAAACTCAGTTCCAATCTG GTGATTCTACCTGGTCAAGATCTCCAATATGTTTTGGCAACCTACG ATACTTCCGCGGTTGAACATGCTGTGGTTTATTACGTTTACAGCCC AAGCCGCTCATTTTCTTACTTTTATCCTTTTAGGTTGCCTATAAAGGGGGTCCCCATCGAATTACAAGTGGAATGCTTCACATGGGACCAAA AACTCTGGTGCCGTCACTTCTGTGTGCTTTGCGGACTCAGAATCTGG TGGACATATCACTCACTCTGGGATGGTGGGCATGGGAGTCAGCTG CACAGTCACCCGGGAAGATGGAACCAATGACTACAAAGACGATGA CGACAAGTGA > Mutant measles envelope protein example, amino acid sequence (SEQ ID NO: 21): MGSRIVINREHLMIDRPYVLLAVLFVMFLSLIGLLAIAGI Petition 870260069374, dated 07 / 13 / 2026, p. 73 / 131 / 75 RLHRAAIYTAEIHKSLSTNLDVTNSIEHQVKDVLTPLFKIIGDEVGLRT PQRFTDLVKFISDKIKFLNPDREYDFRDLTWCINPPERIKLDYDQYCAD VAAEELMNALVNSTLLETRTTNQFLAVSKGNCSGPTTIRGQFSNMSLS LLDLYLGRGYNVSIVTMTSQGMYGGTYLVEKPNLSSKRSELSQLSM YRVFEVGVIRNPGLGAPVFHMTNYLEQPVSNDLSNCMVALGELKLA ALCHGEDSITIPYQGSGKGVSFQLVKLGVWKSPTDMQSWVPLSTDDP VIDRLYLSSHRGVIADNQAKWAVPTTRTDDKLRMETCFQQACKGKIQ ALCENPEWAPLKDNRIPSYGVLSVDLSLTVELKIKIASGFGPLITHGSG MDLYKSNHNNVYWLTIPPMKNLALGVINTLEWIPRFKVSPALFNVPIK EAGGDCHAPTYLPAEVDGDVKLSSNLVILPGQDLQYVLATYDTSAVE HAVVYYVYSPSRSFSYFYPFRLPIKGVPIELQVECFTWDQKLWCRHFC VLADSESGGHITHSGMVGMGVSCTVTREDGTNDYKDDDDK > Proteína de envelope de Nipah mutante exemplificadora, sequencia de DNA (SEQ ID NO: 22): ATGAAGAAGATCAACGAGGGCCTGCTGGACAGCAAG ATCCTGAGCGCCTTCAACACCGTGATTGCCCTGCTGGGCTCTATCG TGATCATCGTGATGAACATCATGATCATCCAGAACTACACCCGGTC CACCGACAACCAGGCCGTGATTAAGGATGCTCTGCAGGGAATCCA GCAGCAGATCAAAGGCCTGGCCGACAAGATCGGCACAGAGATCG GCCCTAAGGTGTCCCTGATCGACACCAGCAGCACCATCACAATCC CCGCCAATATCGGACTGCTGGGAAGCAAGATCAGCCAGAGCACCG CCAGCATCAACGAGAACGTGAACGAGAAGTGCAAGTTCACCCTGC CTCCACTGAAGATCCACGAGTGCAACATCAGCTGCCCCAATCCTCT GCCATTCAGAGAGTACAGACCCCAGACAGAGGGCGTGTCCAATCT CGTGGGCCTGCCTAACAACATCTGCCTGCAGAAAACCAGCAACCA GATCCTGAAGCCTAAGCTGATCTCCTACACACTGCCCGTCGTGGGC CAGAGCGGCACCTGTATTACAGATCCTCTGCTGGCCATGGACGAG GGCTACTTTGCCTACAGCCACCTGGAAAGAATCGGCAGCTGTAGC CGGGGAGTGTCCAAGCAGAGAATCATCGGCGTGGGCGAAGTGCTG Petição 870260069374, de 13 / 07 / 2026, pág. 74 / 131 / 75 GATAGAGGCGACGAAGTGCCCAGCCTGTTCATGACCAATGTGTGG ACCCCTCCTAATCCTAACACCGTGTACCACTGCAGCGCCGTGTACA ACAACGAGTTCTACTACGTGCTGTGCGCCGTGTCCACAGTGGGCG ACCCTATCCTGAACAGCACCTATTGGAGCGGCAGCCTGATGATGA CCAGACTGGCCGTGAAGCCCAAGAGCAATGGCGGCGGATACAACC AGCATCAGCTGGCCCTGCGGTCCATCGAGAAGGGCAGATACGACA AAGTGATGCCTTACGGCCCCAGCGGCATCAAGCAAGGCGATACCC TGTACTTTCCCGCCGTGGGATTTCTCGTGCGGACCGAGTTCAAGTA CAACGACAGCAACTGCCCCATCACCAAGTGCCAGTACAGCAAGCC CGAGAACTGCAGACTGAGCATGGGCATCAGACCCAACAGCCACTA CATCCTGAGAAGCGGCCTGCTGAAGTACAACCTGAGCGACGGCGA GAACCCCAAGGTGGTGTTCATCGAGATCAGCGACCAGCGGCTGTC TATCGGCAGCCCCTCCAAGATCTACGACTCTCTGGGCCAGCCAGTG TTCTACCAGGCCAGCTTTAGCTGGGACACCATGATCAAGTTCGGCG ACGTGCTGACCGTGAATCCCCTGGTGGTCAACTGGCGGAACAATA CCGTGATCAGCCGGCCTGGCCAGTCTCAGTGCCCCAGATTCAATAC CTGTCCTGCCATTTGCGCCGAAGGCGTGTACAATGACGCCTTCCTG ATCGATCGGATCAACTGGATCTCTGCCGGCGTGTTCCTGGACTCTA ATGCCACAGCCGCCAATCCTGTGTTCACCGTGTTCAAGGACAATGA GATCCTGTATCGGGCCCAGCTGGCCTCCGAGGACACAAATGCCCA GAAAACAATCACCAACTGCTTTCTGCTCAAGAACAAGATCTGGTGCATCAGCCTGGTGGAAATCTACGACCCGGCGACAACGTGATCAG GCCCAAGCTGTTCGCCGTGAAGATCCCTGAGCAGTGTACAGGCGG CGGAGGATCTGGCGGAGGTGGAAGCGGAGGCGGTGGATCTGCTAG CGATTACAAGGATGAAGCGGACGGTGGATCTGCTAG CGATTACAAGGATGACGGACGATAAGTGA > Protective envelope development, municipality development amino acid sequence (SEQ ID NO: 23): MKKINEGLLDSKILSAFNTVIALLGSIVIIMIIQNYT RSTDNQAVIKDALQGIQQQIKGLADKIGTEIGPKVSLIDTSSTITIPANIG Petition 870260069374, of 13 / 07 / 2026, p. 75 / 131 / 75 LLGSKISQSTASINENVNEKCKFTLPPLKIHECNISCPNPLPFREYRPQT EGVSNLVGLPNNICLQKTSNQILKPKLISYTLPVVGQSGTCITDPLLAM DEGYFAYSHLERIGSCSRGVSKQRIIGVGEVLDRGDEVPSLFMTNVWT PPNPNTVYHCSAVYNNEFYYVLCAVSTVGDPILNSTYWSGSLMMTRL AVKPKSNGGGYNQHQLALRSIEKGRYDKVMPYGPSGIKQGDTLYFPA VGFLVRTEFKYNDSNCPITKCQYSKPENCRLSMGIRPNSHYILRSGLLK YNLSDGENPKVVFIEISDQRLSIGSPSKIYDSLGQPVFYQASFSWDTMI KFGDVLTVNPLVVNWRNNTVISRPGQSQCPRFNTCPAICAEGVYNDA FLIDRINWISAGVFLDSNATAANPVFTVFKDNEILYRAQLASEDTNAQ KTITNCFLLKNKIWCISLVEIYDTGDNVIRPKLFAVKIPEQCTGGGGSG GGGSGGGGSASDYKDDDDK > IG4 TCR (Variant that binds to NYESO-1 antigen with a binding affinity of 32 gM), amino acid sequence (SEQ ID NO: 24): MSIGLLCCAALSLLWAGPVNAGVTQTPKFQVLKTGQS MTLQCAQDMNHEYMSWYRQDPGMGLRLIHYSVGAGITDQGEVPNG YNVSRSTTEDFPLRLLSAAPSQTSVYFCASSYVGNTGELFFGEGSRLT VLEDLKNVFPPEVAVFEPSEAEISHTQKATLVCLATGFYPDHVELSW WVNGKEVHSGVSTDPQPLKEQPALNDSRYCLSSRLRVSATFWQNPR NHFRCQVQFYGLSENDEWTQDRAKPVTQIVSAEAWGRADCGFTSES YQQGVLSATILYEILLGKATLYAVLVSALVLMAMVKRKDSRGGSAT NFSLLKQAGDVEENPGPMETLLGLLILWLQLQWVSSKQEVTQIPAAL SVPEGENLVLNCSFTDSAIYNLQWFRQDPGKGLTSLLLIQSSQREQTS GRLNASLDKSSGSSTLYIAASQPGDSATYLCAVRPTSGGSYIPTFGRGT SLIVHPYIQNPDPAVYQLRDSKSSDKSVCLFTDFDSQTNVSQSKDSDV YITDKTVLDMRSMDFKSNSAVAWSNKSDFACANAFNNSIIPEDTFFPS PESSCDVKLVEKSFETDTNLNFQNLSVIGFRILLLKVAGFNLLMTLRL WSSAAA > IG4 TCR (Variant that binds to NYESO-1 antigen with a binding affinity of 84 nM), amino acid sequence (SEQ ID NO: 25): Petition 870260069374, dated 07 / 13 / 2026, page 76 / 131 / 75 MSIGLLCCAALSLLWAGPVNAGVTQTPKFQVLKTGQS MTLQCAQDMNHEYMSWYRQDPGMGLRLIHYSVGAQTTDQGEVPNG YNVSRSTIEDFPLRLLSAAPSQTSVYFCASSYLGNTGELFFGEGSRLTV LEDLKNVFPPEVAVFEPSEAEISHTQKATLVCLATGFYPDHVELSWW VNGKEVHSGVSTDPQPLKEQPALNDSRYCLSSRLRVSATFWQNPRNH FRCQVQFYGLSENDEWTQDRAKPVTQIVSAEAWGRADCGFTSESYQ QGVLSATILYEILLGKATLYAVLVSALVLMAMVKRKDSRGGSATNFS LLKQAGDVEENPGPMETLLGLLILWLQLQWVSSKQEVTQIPAALSVP EGENLVLNCSFTDSAIYNLQWFRQDPGKGLTSLLLIQSSQREQTSGRL NASLDKSSGSSTLYIAASQPGDSATYLCAVRPMIGGTYIPTFGRGTSLI VHPYIQNPDPAVYQLRDSKSSDKSVCLFTDFDSQTNVSQSKDSDVYIT DKTVLDMRSMDFKSNSAVAWSNKSDFACANAFNNSIIPEDTFFPSPES SCDVKLVEKSFETDTNLNFQNLSVIGFRILLLKVAGFNLLMTLRLWSS AAA > IG4 TCR (Variant that binds to NYESO-1 antigen with a binding affinity of 5 nM), amino acid sequence (SEQ ID NO: 26): MSIGLLCCAALSLLWAGPVNAGVTQTPKFQVLKTGQS MTLQCAQDMNHEYMSWYRQDPGMGLRLIHYSVGAGTTDRGEVPNG YNVSRSTIEDFPLRLLSAAPSQTSVYFCASSYVGDTGELFFGEGSRLTV LEDLKNVFPPEVAVFEPSEAEISHTQKATLVCLATGFYPDHVELSWW VNGKEVHSGVSTDPQPLKEQPALNDSRYCLSSRLRVSATFWQNPRNH FRCQVQFYGLSENDEWTQDRAKPVTQIVSAEAWGRADCGFTSESYQ QGVLSATILYEILLGKATLYAVLVSALVLMAMVKRKDSRGGSATNFS LLKQAGDVEENPGPMETLLGLLILWLQLQWVSSKQEVTQIPAALSVP EGENLVLNCSFTDSAIYNLQWFRQDPGKGLTSLLLIQSSQREQTSGRL NASLDKSSGSSTLYIAASQPGDSATYLCAVRPLLDGTYIPTFGRGTSLI VHPYIQNPDPAVYQLRDSKSSDKSVCLFTDFDSQTNVSQSKDSDVYIT DKTVLDMRSMDFKSNSAVAWSNKSDFACANAFNNSIIPEDTFFPSPES SCDVKLVEKSFETDTNLNFQNLSVIGFRILLLKVAGFNLLMTLRLWSS Petition 870260069374, dated 07 / 13 / 2026, page 77 / 131 / 75 AAA > IG4 TCR (Variant that binds to NYESO-1 antigen with a binding affinity of 26 pM), amino acid sequence (SEQ ID NO: 27): MSIGLLCCAALSLLWAGPVNAGVTQTPKFQVLKTGQS MTLQCAQDMNHEYMSWYRQDPGMGLRLIHYSVAIQTTDQGEVPNG YNVSRSTIEDFPLRLLSAAPSQTSVYFCASSYLGNTGELFFGEGSRLTV LEDLKNVFPPEVAVFEPSEAEISHTQKATLVCLATGFYPDHVELSWW VNGKEVHSGVSTDPQPLKEQPALNDSRYCLSSRLRVSATFWQNPRNH FRCQVQFYGLSENDEWTQDRAKPVTQIVSAEAWGRADCGFTSESYQ QGVLSATILYEILLGKATLYAVLVSALVLMAMVKRKDSRGGSATNFS LLKQAGDVEENPGPMETLLGLLILWLQLQWVSSKQEVTQIPAALSVP EGENLVLNCSFTDSAIYNLQWFRQDPGKGLTSLLLITPWQREQTSGRL NASLDKSSGSSTLYIAASQPGDSATYLCAVRPLLDGTYIPTFGRGTSLI VHPYIQNPDPAVYQLRDSKSSDKSVCLFTDFDSQTNVSQSKDSDVYIT DKTVLDMRSMDFKSNSAVAWSNKSDFACANAFNNSIIPEDTFFPSPES SCDVKLVEKSFETDTNLNFQNLSVIGFRILLLKVAGFNLLMTLRLWSS AAA > 868 TCR (Cadeia Beta-P2A-Cadeia Alfa), amino acid sequence (SEQ ID NO: 31): MSIGLLCCAALSLLWAGPVNADAGVTQSPTHLIKTRGQ QVTLRCSPKQGHDTVSWYQQALGQGPQFIFQYYEEEERQRGNFPDRF SGHQFPNYSSELNVNALLLGDSALYLCASSDTVSYEQYFGPGTRLTVT EDLKNVFPPEVAVFEPSEAEISHTQKATLVCLATGFYPDHVELSWWV NGKEVHSGVSTDPQPLKEQPALNDSRYCLSSRLRVSATFWQDPRNHF RCQVQFYGLSENDEWTQDRAKPVTQIVSAEAWGRADCGFTSESYQQ GVLSATILYEILLGKATLYAVLVSALVLMAMVKRKDSRGGSATNFSL LKQAGDVEENPGPMETLLGLLILWLQLQWVSSKEVEQNSGPLSVPEG AIASLNCTYSDRGSQSFFWYRQYSGKSPELIMFIYSNGDKEDGRFTAQ LNKASQYISLLIRDSKLSDSATYLCAVRTNSGYALNFGKGTSLLVTPHI Petição 870260069374, de 13 / 07 / 2026, pág. 78 / 131 / 75 QKPDPAVYQLRDSKSSDKSVCLFTDFDSQTNVSQSKDSDVYITDKTV LDMRSMDFKSNSAVAWSNKSDFACANAFNNSIIPEDTFFPSPESSCDV KLVEKSFETDTNLNFQNLSVIGFRILLLKVAGFNLLMTLRLWSS >CMV C7 TCR, sequence amino ID NO:3: MGTRLLFWVAFCLLGADHTGAGVSQSPSNKVTEKGKDVELRCDPISG HTALYWYRQRLGQGLEFLIYFQGNSAPDKSGLPSDRFSAERTGESVST LTIQRTQQEDSAVYLCASSQTQLWETQYFGPGTRLLVLEDLKNVFPPESG VAVFEPSEAEISHTQKATLVCLATGFYPDHVELSWWVNGKEVHSGVS TDPQPLKEQPALNDSRYCLSSSRLRVSATFWQNPRNHFRCQVQFYGLS ENDEWTQDRAKPVTQIVSAEAWGRADCGFTSESYQQGVLSATILYEI LLGKATLYAVLVSALVLMAMVKRKDSRGGSATNFSLLKQAGDVEEN PGPMEKNPLAAPLLILWFHLDCVSSILNVEQSPQSLHVQEGDSTNFTC SFPSSNFYALHWYRWETAKSPEALFVMTLNGDEKKKGRISATLNTKE GYSYLYIKGSQPEDSATYLCAFITGNQFYFGTGTSLTVIPNIQNPDPAV YQLRDSKSSDKSVCLFTDFDSQTNVSQSKDVYITDKTVLDMRMSMD FKSNSAVAWSNKSDFACANAFNNSIIPEDTFFPSPESSCDVKLVEKSFE TLDNFLAVNGRAQLQVLKVLKVL > SL9 pMHC (bolded SL9 peptide portion), amino acid sequence (SEQ ID NO: 35): MSRSVALAVLALLSLSGLEASLYNTVATLGGGASGGGGSGGGGSIQR TPKIQVYSRHPAENGKSNFLNCYVSGFHPSDIEVDLLKNGERIEKVEH SDLSFSKDWSFYLLYYTEFTPTEKDEYACRVNHVTLSQPKIVKWDRD MGGGGSGGGGSGGGGSGGGGSHSMRYFFTSVSRPGRGEPRFIAVGY VDDTQFVRFDSDAASQRMEPRAPWIEQEGPEYWDGETRKVKAHSQT HRVDLGTLRGAYNQSEAGSHTVQRMYGCDVGSDWRFLRGYHQYAY DGKDYIALKEDLRSWTAADMAAQTTKHKWEAAHVAEQLRAYLEGT CVEWLRRYLENGKETLQRTDAPKTHMTHHAVSDHEATLRCWALSFY PAEITLTWQRDGEDQTQDTELVETRPAGDGTFQKWAAVVVPSGQEQ RYTCHVQHEGLPKPLTLRWEPSSQPTIPIVGIIAGLVLFGAVITGAVVA Petition 870260069374, dated 07 / 13 / 2026, pp. 79 / 131 / 75 AVMWRRKSS > SL9 pMHC (SL9 peptide portion in bold), amino acid sequence (SEQ ID NO: 37): MSRSVALAVLALLSLSGLEANLVPMVATVGASGGSGG GSGGGGSIQRTPKIQVYSRHPAENGKSNFLNCYVSGFHPSDIEVDLLK NGERIEKVEHSDLSFSKDWSFYLLYYTEFTPTEKDEYACRVNHVTLSQ PKIVKWDRDMGGGGSGGGGSGGGGSGGGGSHSMRYFFTSVSRPGRG EPRFIAVGYVDDTQFVRFDSDAASQRMEPRAPWIEQEGPEYWDGETR KVKAHSQTHRVDLGTLRGAYNQSEAGSHTVQRMYGCDVGSDWRFL RGYHQYAYDGKDYIALKEDLRSWTAADMAAQTTKHKWEAAHVAE QLRAYLEGTCVEWLRRYLENGKETLQRTDAPKTHMTHHAVSDHEAT LRCWALSFYPAEITLTWQRDGEDQTQDTELVETRPAGDGTFQKWAA VVVPSGQEQRYTCHVQHEGLPKPLTLRWEPSSQPTIPIVGIIAGLVLFG AVITGAVVAAVMWRRKSS > MHC disulfide trap comprising the Y84C mutation (in bold) and linker position 2 being a C (in bold); shown with the HGH Signal Peptide (underlined) and the GL9 peptide (italicized), amino acid sequence (SEQ ID NO: 39): MATGSRTSLLLAFGLLCLPWLQEGSA GILGFVFTL GCSGGSGGGSGGG GSIQRTPKIQVYSRHPAENGKSNFLNCYVSGFHPSDIEVDLLKNGERIE KVEHSDLSFSKDWSFYLLYYTEFTPTEKDEYACRVNHVTLSQPKIVK WDRDMGGGGSGGSGSGGSGSGGGSGGSHSMRYFFTSVSRPGRGEPR FIAVGYVDDTQFVRFDSDAASQRMEPRAPWIEQEGPEYWDGETRKV KAHSQTHRVDLGTLRGCYNQSEAGSHTVQRMYGCDVGSDWRFLRG YHQYAYDGKDYIALKEDLRSWTAADMAAQTTKHKWEAAHVAEQL RAYLEGTCVEWLRRYLENGKETLQRTDAPKTHMTHHAVSDHEATLR CWALSFYPAEITLTWQRDGEDQTQDTELVETRPAGDGTFQKWAAVV VPSGQEQRYTCHVQHEGLPKPLTLRWEPSSQPTIPIVGIIAGLVLFGAVI TGAVVAAVMWRRKSS Petition 870260069374, dated 07 / 13 / 2026, page 80 / 131 / 75 > GL9 pMHC (portion of the GL9 peptide in bold), amino acid sequence (SEQ ID NO: 41): MSRSVALAVLALLSLSGLEASLYNTVATLGGGASGGGGSGGGGSIQR TPKIQVYSRHPAENGKSNFLNCYVSGFHPSDIEVDLLKNGERIEKVEH SDLSFSKDWSFYLLYYTEFTPTEKDEYACRVNHVTLSQPKIVKWDRD MGGGGSGGGGSGGGGSGGGGSHSMRYFFTSVSRPGRGEPRFIAVGY VDDTQFVRFDSDAASQRMEPRAPWIEQEGPEYWDGETRKVKAHSQT HRVDLGTLRGAYNQSEAGSHTVQRMYGCDVGSDWRFLRGYHQYAY DGKDYIALKEDLRSWTAADMAAQTTKHKWEAAHVAEQLRAYLEGT CVEWLRRYLENGKETLQRTDAPKTHMTHHAVSDHEATLRCWALSFY PAEITLTWQRDGEDQTQDTELVETRPAGDGTFQKWAAVVVPSGQEQ RYTCHVQHEGLPKPLTLRWEPSSQPTIPIVGIIAGLVLFGAVITGAVVA AVMWRRKSS > CD80, sequência de aminoácido (SEQ ID NO: 43): MGHTRRQGTSPSKCPYLNFFQLLVLAGLSHFCSGVIHVTKEVKEVAT LSCGHNVSVEELAQTRIYWQKEKKMVLTMMSGDMNIWPEYKNRTIF DITNNLSIVILALRPSDEGTYECVVLKYEKDAFKREHLAEVTLSVKAD FPTPSISDFEIPTSNIRRIICSTSGGFPEPHLSWLENGEELNAINTTVSQDP ETELYAVSSKLDFNMTTNHSFMCLIKYGHLRVNQTFNWNTTKQEHFP DNLLPSWAITLISVNGIFVICCLTYCFAPRCRE > CD86,amino acid sequence (SEQ ID NO: 45): MDPQCTMGLSNILFVMAFLLSGAAPLKIQAYFNETADLPCQFANSQN QSLSELVVFWQDQENLVLNEVYLGKEKFDSVHSKYMGRTSFDSDSW TLRLHNLQIKDKGLYQCIIHHKKPTGMIRIHQMNSELSVLANFSQPEIV PISNITENVYINLTCSSIHGYPEPKKMSVLLRTKNSTIEYDGVMQKSQD NVTELYDVSISLSVSFPDVTSNMTIFCILETDKTRLLSSPFSIELEDPQPP PDHIPWITAVLPTVIICVMVFCLILWKWKKKKR > Mouse Fab H57-597 anti-TCR Clone Beta antibody (light chain-P2A-heavy chain, transmembrane domain, Petition 870260069374, dated 07 / 13 / 2026, page 81 / 131 / 75 PDGFR), amino acid sequence: (SEQ ID NO: 47): METDTLLLWVLLLWVPGSTGADYKDDDDKDIQMTQSPSSLPASLGD RVTINCQASQDISNYLNWYQQKPGKAPKLLIYTNKLADGVPSRFSG SGSGRDSSFTISSLESEDIGSYCQQYYNYPWTFGPGTKLEIKRADAKP TVSIFPPSSEQLGTGSATLVCFVNNFYPKDINVKWKVDGSEKRDGVLQ SVTDQDSKDSTYSLSSTLSLTKADYERHNLYTCEVTHKTSTAAIVKTL NRNECGSGATNFSLLKQAGDVEENPGPMVPCTLLLLLAAALAPTQTR AEVQLVESGGGLVQPGKSLKLSCEASGFTFSGYGMHWVRQAPGRGL ESVAYITSSINIKYADAVKGRFTVSRDNAKNLLFLQMNILKSEDTAM YYCARFDWDKNYWGQGTMVTVSSAKTTAPSVYPLAPACCDSTTSTTN TVTLGCLVKGYFPEPPVTVIWNSGALTSGVHTFPSVLHSGLYSLSSSVT VPSSTWPSQTVTCNVAHPASSTTVDLKIEAVGQDTQEVIVVPHSLPFC VVVISAILVLTVLTQPRWMLKPO 145-2C11 anti-TCR Clone Beta de camundongo (light chain-P2A-heavy chain, PDGFR transmembrane domain), amino acid sequence: 49): METDTLLLWVLLLWVPGSTGADYKDDDDKYELIQPSSASVTVGETV KITSCGDQLPKNFAYWFQQKSDKNILLLIYMDNKRPSGIPERFSGSTSG TTATLTISGAQPEDEAAYYCLSSYGDNNDLVFGSGTQLTVLRGPKSSP KVTVFPPSPEELRTNKATLVCLVNDFYPGSATVTWKANGATINDGVK TTKPSKQGQNYMTSSYLSLTADQWKSHNRVSCQVTHEGETVEKSLSP AECLGSGATNFSLLKQAGDVEENPGPMVPCTLLLLLLAAALAPTQTRA EVYLVESGGDLVQPGSSLKVSCAASGFTFSDFWMYWVRQAPGKGLE WVGRIKNIPNNYATEYADSVRGRFTISRDDSRNSIYLQMNRLRVDDT AIYYCTRAGRFDHFDYWGQGTMVTVSSATTTAPSVYPLAPACDSTTS TTDTVTLGCLVKGYFPEPVTVSWNSGALTSGVHTFPSVLHSGLYSLSS SVTVPSSTWPKQPITCNVAHPASSTKVDKKIEPRAVGQDTQEVIVVPH SLPFKVVVISAILALVVLTIISLIILIMLWQKKPR* >Cocal virus glycoprotein, amino acid sequence: Petition 870260069374, dated 07 / 13 / 2026, page 82 / 131 / 75 (SEQ ID NO: 51): MNFLLLTFIVLPLCSHAKFSIVFPQSQKGNWKNVPSSYHYCPSSSDQN WHNDLLGITMKVKMPKTHKAIQADGWMCHAAKWITTCDFRWYGP KYITHSIHSIQPTSEQCKESIKQTKQGTWMSPGFPPQNCGYATVTDSV AVVVQATPHHVLVDEYTGEWIDSQFPNGKCETEECETVHNSTVWYS DYKVTGLCDATLVDTEITFFSEDGKKESIGKPNTGYRSNYFAYEKGD KVCKMNYCKHAGVRLPSGVWFEFVDQDVYAAAKLPECPVGATISAP TQTSVDVSLILDVERILDYSLCQETWSKIRSKQPVSPVDLSYLAPKNPG TGPAFTIINGTLKYFETRYIRIDIDNPIISKMVGKISGSQTERELWTEWFP YEGVEIGPNGILKTPTGYKFPLFMIGHGMLDSDLHKTSQAEVFEHPHL AEAPKQLPEEETLFFGDTGISKNPVELIEGWFSSWKSTVVTFFFAIGVFI LLYVVARIVIAVRYRYQGSNNKRIYNDIEMSRFRK* >Cocal virus glycoprotein, DNA sequence: (SEQ ID NO: 52): ATGAACTTTCTGCTGCTCACGTTTATCGTACTCCCGTTGTGCTCTCA TGCGAAATTTTCAATAGTCTTTCCTCAGTCCCAGAAAGGGAATTGG AAAAATGTTCCCTCCAGTTACCACTATTGTCCCTCCTCCTCTGACC AAAACTGGCACAATGACTTGCTCGGGATTACAATGAAAGTAAAGA TGCCGAAAACCCATAAAGCCATACAGGCGGATGGGTGGATGTGTC ACGCTGCGAAGTGGATCACTACATGCGATTTCCGGTGGTATGGCCC TAAGTACATTACACACTCTATCCATAGCATACAGCCGACATCAGA GCAATGCAAAGAGAGTATTAAACAGACCAAACAAGGGACATGGA TGAGCCCTGGCTTTCCACCTCAGAATTGTGGGTACGCGACCGTCAC GGATAGTGTCGCTGTTGTGGTGCAGGCCACGCCACATCACGTACTC GTAGATGAATATACTGGTGAATGGATCGACTCCCAATTCCCGAAT GGGAAATGTGAGACGGAAGAGTGCGAAACAGTGCATAACTCAAC CGTTTGGTATTCCGATTACAAGGTTACTGGTCTTTGCGACGCCACC CTCGTGGATACCGAGATCACGTTTTTTAGTGAGGATGGCAAGAAA GAGTCAATAGGCAAACCTAATACTGGCTACCGGAGTAACTATTTC Petição 870260069374, de 13 / 07 / 2026, pág. 83 / 131 / 75 GCTTACGAGAAGGGTGACAAGGTATGTAAAATGAACTATTGCAAG CATGCGGGAGTGCGACTCCCCAGTGGGGTATGGTTCGAATTTGTTG ACCAAGACGTATACGCCGCTGCGAAGTTGCCAGAATGCCCCGTAG GCGCGACCATTTCAGCACCTACCCAAACGCTTCCGTTGACCTT GATACTGGATGTAGAGCGAATCCTGGACTACAGCTCTGCCAGGA AACGTGGTCAAAAAATAAGAAGTAAGCAGCCAGTTTCACCCGTGGA TCTGTCTTATCTGGCCAAAAAACCCGGGCACGGGCCCTGCTTTT ACCATAATTAACGGAACGCTTAAATACTTCGAAACCCGCTACATTA GAATCGATATAGACAATCCCTATTATCAGCAAGATGGTAGGGAAGA TATCTGGGTCTCAAACGGAGCGAGAATTGTGGACGGAGTGGTTCC CTTATGAGGGAGTGGAAATTGGGCCCAACGGGATCCTCAAGACCC CAACGGGTTACAAGTTCCCTCTGTTTATGATCGGGCCATGGCATGTT GGACAGTGACTTGCACAAAACATCTCAGGCAGAGGTTTTCGAACA TCCACATTTGGCGGAGGCGCCCAAGCAACTTCCAGAAGAAGAAAC TCTCTTCTTTGGAGATACAGGCATTTCAAAAAATCCTGTAGAACTG ATAGAAGGGTGTTCTCTTCCTGGAAATCAATCCGTTTCTTTTTT TCTTTGCAATAGGCGTATTTATACTCCTGTACGTCGTAGCCCGCAT TGTGATCGCAGTACGATACAGATACCAGGGCAGTAACAATAAACG CATATATAATGACATCGAAATGTCAAGGTTCCGAAAGtga > Cocal-morto (mutations to eliminate native tropism in bold in protein sequence;These are K64Q and R371A, counting from the start codon), amino acid sequence: (SEQ ID NO: 53): MNFLLLTFIVLPLCSHAKFSIVFPQSQKGNWKNVPSSYHYCPSSSDQN WHNDLLGITMKVKMPQTHKAIQADGWMCHAAKWITTCDFRWYGP KYITHSIHSIQPTSEQCKESIKQTKQGTWMSPGFPPQNCGYATVTDSV AVVVQATPHHVLVDEYTGEWIDSQFPNGKCETEECETVHNSTVWYS DYKVTGLCDATLVDTEITFFSEDGKKESIGKPNTGYRSNYFAYEKGD KVCKMNYCKHAGVRLPSGVWFEFVDQDVYAAAKLPECPVGATISAP TQTSVDVSLILDVERILDYSLCQETWSKIRSKQPVSPVDLSYLAPKNPG; Petition 870260069374, dated 07 / 13 / 2026, page 84 / 131 / 75 TGPAFTIINGTLKYFETRYIRIDIDNPIISKMVGKISGSQTEAELWTEWF PYEGVEIGPNGILKTPTGYKFPLFMIGHGMLDSDLHKTSQAEVFEHPH LAEAPKQLPEEETLFFGDTGISKNPVELIEGWFSSWKSTVVTFFFAIGV FILLYVVARIVIAVRYRYQGSNNKRIYNDIEMSRFRK >Dead Cocal (mutations to ablate native tropism), DNA sequence: (SEQ ID NO: 54): ATGAACTTTCTGCTGCTCACGTTTATCGTACTCCCGTTGTGCTCTCA TGCGAAATTTTCAATAGTCTTTCCTCAGTCCCAGAAAGGGAATTGG AAAAATGTTCCCTCCAGTTACCACTATTGTCCCTCCTCCTCTGACC AAAACTGGCACAATGACTTGCTCGGGATTACAATGAAAGTAAAGA TGCCGcagACCCATAAAGCCATACAGGCGGATGGGTGGATGTGTCA CGCTGCGAAGTGGATCACTACATGCGATTTCCGGTGGTATGGCCCT AAGTACATTACACACTCTATCCATAGCATACAGCCGACATCAGAG CAATGCAAAGAGAGTATTAAACAGACCAAACAAGGGACATGGAT GAGCCCTGGCTTTCCACCTCAGAATTGTGGGTACGCGACCGTCACG GATAGTGTCGCTGTTGTGGTGCAGGCCACGCCACATCACGTACTCG TAGATGAATATACTGGTGAATGGATCGACTCCCAATTCCCGAATG GGAAATGTGAGACGGAAGAGTGCGAAACAGTGCATAACTCAACC GTTTGGTATTCCGATTACAAGGTTACTGGTCTTTGCGACGCCACCC TCGTGGATACCGAGATCACGTTTTTTAGTGAGGATGGCAAGAAAG AGTCAATAGGCAAACCTAATACTGGCTACCGGAGTAACTATTTCG CTTACGAGAAGGGTGACAAGGTATGTAAAATGAACTATTGCAAGC ATGCGGGAGTGCGACTCCCCAGTGGGGTATGGTTCGAATTTGTTGA CCAAGACGTATACGCCGCTGCGAAGTTGCCAGAATGCCCCGTAGG CGCGACCATTTCAGCACCTACCCAAACGTCCGTTGACGTCTCCTTG ATACTGGATGTAGAGCGAATCCTGGACTACAGTCTCTGCCAGGAA ACGTGGTCAAAAATAAGAAGTAAGCAGCCAGTTTCACCCGTGGATCTGTCTTATCTGGCGCCAAAAAACCCGGGCACGGGCCCTGCTTTTA CCATAATTAACGGAACGCTTAAATACTTCGAAACCCGCTACATTAG Petition 870260069374, of 13 / 07 / 2026, p. 85 / 131 / 75 AATCGATATAGACAATCCCTATTATCAGCAAGATGGTAGGGAAGAT ATCTGGGTCTCAAACGGGGCCGAATTGTGGACGGAGTGGTTCCCT TATGAGGGAGTGGAAATTGGGCCCAACGGGATCCTCAAGACCCCA ACGGGTTACAAGTTCCCTCTGTTTATGTCGGCCATGGCATGGC ACAGTGACTTGCACAAAACATCTCAGGCAGAGGTTTTCGAACATC CACATTTGGCGGAGGCGCCCAAGCAACTTCCAGAAGAAAACTC TCTTCTTTGGAGATACAGGCATTTCAAAAAATCCTGTAGAACTGAT AGAAGGGTGGTTCTCTTCCTGGAAATCAACGGTCACGTTTCTTTC TTTGCAATAGGCGTATTTATACTCCTGTACGTCGTAGCCCGCATTG TGATCGCAGTACGATACAGATACCAGGGCAGTAACAATAAACGCA TATATAATGACATCGAAATGTCAAGGTTCCGAAAGtga. Petition 870260069374, of 13 / 07 / 2026, p. 86 / 131

Claims

1 / 6 CLAIMS 1. Retrovirus, characterized in that it comprises a lentivirus, the lentivirus comprising: (a) a nucleic acid; (b) a viral envelope comprising (i) a VSV-G (vesicular stomatitis virus) envelope protein comprising an amino acid sequence at least 95% identical to SEQ ID NO: 13, wherein the VSV-G envelope protein comprises one or more amino acid mutations at position 47 (lysine, K) and / or at position 354 (arginine, R), wherein the amino acid mutation(s) decrease(s) the native viral tropism of the VSV-G envelope protein compared with the non-mutated VSV-G envelope protein; and a non-viral membrane-bound protein comprising a membrane-bound domain and an extracellular labeling domain that is capable of binding to a ligand expressed on the surface of a T cell or B cell.

2. Retrovirus, according to claim 1, characterized in that the nucleic acid encodes an mRNA, a double-stranded DNA, an antisense RNA, a microRNA, a gene of interest or a protein.

3. Retrovirus, according to claim 1, characterized in that one or more amino acid mutations comprise an amino acid mutation at position K47 or at position R354.

4. Retrovirus, according to claim 1, characterized in that one or more amino acid mutations comprise an amino acid mutation at position K47 and at position R354.

5. Retrovirus, according to claim 1, characterized in that one or more amino acid mutations comprise a K47A or K47Q amino acid substitution and / or an R354A or R354Q amino acid substitution.

6. Retrovirus, according to claim 1, characterized by the fact that the extracellular labeling domain comprises a protein, a peptide or an antibody.

7. Retrovirus, according to claim 6, characterized in that the extracellular labeling domain comprises an interleukin-13 protein domain, a CD80 protein domain, a full-length antibody, an antibody fragment, a nanobody, a single-chain antibody (scFv), an anti-CD19 antibody, an anti-TCR antibody, or an anti-CD3 antibody.

8. Retrovirus, according to claim 1, characterized in that the ligand comprises a T cell receptor (TCR), a cytokine receptor, a cytokine, a T cell surface marker, CD3, CD19 or CD20.

9. Composition for use in delivering a nucleic acid to a cell, characterized in that the cell is a T cell or a B cell, the composition comprising: (a) a lentivirus, the lentivirus comprising: a nucleic acid and a viral envelope comprising (i) a VSV-G envelope protein comprising an amino acid sequence at least 95% identical to SEQ ID NO: 13, wherein the VSV-G envelope protein comprises one or more amino acid mutations at position 47 (lysine, K) and / or at position 354 (arginine, R), wherein the amino acid mutation(s) decrease(s) the native viral tropism of the VSV-G envelope protein compared with the non-mutated VSV-G envelope protein; and (ii) a non-viral membrane-bound protein comprising a transmembrane domain and an extracellular labeling domain that binds to a ligand expressed on the surface of a T cell or a B cell;and (b) bring the lentivirus into contact with the T cell or B cell, thereby releasing the nucleic acid to the T cell or B cell.; 10. Composition, according to claim 9, Petition 870260069374, dated 07 / 13 / 2026, page 88 / 131 3 / 6 characterized in that the nucleic acid encodes an mRNA, a double-stranded DNA, an antisense RNA, a microRNA, a gene of interest or a protein.

11. Composition according to claim 9, characterized in that one or more amino acid mutations comprise an amino acid mutation at position K47 or at position R354.

12. Composition according to claim 9, characterized in that one or more amino acid mutations comprise an amino acid mutation at position K47 and at position R354.

13. Composition according to claim 9, characterized in that one or more amino acid mutations comprise a K47A or K47Q amino acid substitution and / or an R354A or R354Q amino acid substitution.

14. Composition according to claim 9, characterized in that the extracellular labeling domain comprises a protein, a peptide or an antibody.

15. Composition, according to claim 14, characterized in that the extracellular labeling domain comprises an interleukin-13 protein domain, a CD80 protein domain, a full-length antibody, an antibody fragment, a nanobody, an scFv, an anti-CD19 antibody, an anti-TCR antibody, or an anti-CD3 antibody.

16. Composition according to claim 9, characterized in that the ligand comprises a T cell receptor (TCR), a cytokine receptor, a cytokine, a T cell surface marker, CD3, CD19 or CD20.

17. Composition for use in delivering a nucleic acid to a cell, characterized in that it comprises a lentivirus, the lentivirus comprising: (a) a nucleic acid; (b) a viral envelope comprising (i) a VSV-G envelope protein comprising an amino acid sequence at least 95% identical to SEQ ID NO: 13, wherein the VSV-G envelope protein comprises one or more amino acid mutations at position 47 (lysine, K) and / or at position 354 (arginine, R), wherein the amino acid mutation(s) decrease(s) the native viral tropism of the VSV-G envelope protein compared with the non-mutated VSV-G envelope protein; and (ii) a nonviral membrane-bound protein comprising a transmembrane domain and an extracellular labeling domain comprising an anti-CD3 antibody.

18. Composition according to claim 17, characterized in that the nucleic acid encodes an mRNA, a double-stranded DNA, an antisense RNA, a microRNA, a gene of interest or a protein.

19. Composition according to claim 17, characterized in that one or more amino acid mutations comprise an amino acid mutation at position K47 or at position R354.

20. Composition according to claim 17, characterized in that one or more amino acid mutations comprise an amino acid mutation at position K47 and at position R354.

21. Composition, according to claim 17, characterized in that one or more amino acid mutations comprise a K47A or K47Q amino acid substitution and / or an R354A or R354Q amino acid substitution. Petition 870260069374, dated 13 / 07 / 2026, pp. 90 / 131 5 / 6 22. Composition, according to claim 17, characterized in that the viral envelope further comprises a non-viral membrane protein comprising a transmembrane domain and an extracellular labeling domain comprising a full-length antibody, an antibody fragment, a nanobody, a scFv or an anti-TCR antibody.

23. Composition according to claim 17, characterized in that the viral envelope further comprises a non-viral membrane protein comprising a CD80 protein comprising an extracellular CD80 domain and a transmembrane domain.

24. Composition for use in delivering a nucleic acid to a cell, characterized in that the cell is a T cell, the composition comprising: (a) a lentivirus, the lentivirus comprising: a nucleic acid and a viral envelope comprising (i) a VSV-G envelope protein comprising an amino acid sequence at least 95% identical to SEQ ID NO: 13, wherein the VSV-G envelope protein comprises one or more amino acid mutations at position 47 (lysine, K) and / or at position 354 (arginine, R), wherein the amino acid mutation(s) decrease(s) the native viral tropism of the VSV-G envelope protein compared with the non-mutated VSV-G envelope protein; and (ii) a non-viral membrane-bound protein comprising a transmembrane domain and an extracellular labeling domain comprising an anti-CD3 antibody; (b) to bring the lentivirus into contact with the T cell, thereby releasing the nucleic acid to the T cell.

25. Composition according to claim 24, characterized in that the nucleic acid encodes an mRNA, a double-stranded DNA, an antisense RNA, a microRNA, a gene of interest or a protein.

26. Composition according to claim 24, characterized in that one or more amino acid mutations comprise an amino acid mutation at position K47 or at position R354.

27. Composition according to claim 24, characterized in that one or more amino acid mutations comprise an amino acid mutation at position K47 and at position R354.

28. Composition according to claim 24, characterized in that one or more amino acid mutations comprise a K47A or K47Q amino acid substitution and / or an R354A or R354Q amino acid substitution.

29. Composition according to claim 24, characterized in that the viral envelope further comprises a non-viral membrane-bound protein comprising a transmembrane domain and an extracellular labeling domain comprising a full-length antibody, an antibody fragment, a nanobody, a scFv or an anti-TCR antibody.

30. Composition, according to claim 24, characterized in that the viral envelope further comprises a non-viral membrane-bound protein comprising a CD80 protein comprising an extracellular CD80 domain and a transmembrane domain. Petition 870260069374, dated 13 / 07 / 2026, pp. 92 / 131

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