Protein, nucleic acid, genetically modified bacterial cell, use of a population of cytotoxic lymphocytes, and methods for manufacturing a genetically modified cytotoxic lymphocyte.

Abstract

The present description provides proteins, such as antibodies, that include an antigen-binding portion that specifically binds to programmed death ligand 1 (pd-l1). Nucleic acids encoding the proteins and cells (e.g., genetically modified cytotoxic lymphocytes) containing such nucleic acids are also provided. In some embodiments, a method in question involves reducing the interaction between pd-l1 in a first cell and pd-1 in a second cell. In some cases, the contact is in vivo. For example, the methods and compositions provided can be used in the treatment of viral infection and cancer, such as the treatment of solid tumors through ACT or through administration of a protein in question that specifically binds to pd-l1.

Description

Protein, nucleic acid, genetically modified bacterial cell, use of a population of cytotoxic lymphocytes, and methods for manufacturing a genetically modified cytotoxic lymphocyte. Cross-reference to related applications.

[001] This application claims the benefit of the US Provisional Application. No. 62 / 359.612, filed on July 7, 2016, the entirety of which is expressly incorporated herein by reference. SEQUENCE LISTING

[002] This application contains a Sequence Listing that was submitted electronically in ASCII format and is hereby incorporated by reference in its entirety. Said ASCII copy, created on July 7, 2017, is named 116983-5024_ST25.txt and is 101,943 bytes in size. INTRODUCTION

[003] Adoptive Cell Transfer (ACT) is a treatment method in which autologous T cells from a patient are expanded, manipulated ex vivo, and then reintroduced into the patient to exert a response, for example, an antitumor response. Tumor-Infiltrating Lymphocytes (TILs) generally refer to a heterogeneous population of lymphocytes that can be found in the tumor microenvironment. The general rationale of ACT therapy using TILs is that the antitumor immune response can be enhanced by removing cells with antitumor potential from the immunosuppressive tumor microenvironment, expanding the cells in vitro, and then returning the expanded cell population to tumor sites to kill tumor cells and possibly other tumor-supporting cellular targets, such as vascular endothelial cells. Lee and Margolin, Curr. Oncol. Rep. 2012; 14(5) 468-474.

[004] Programmed death 1 (PD-1) is a well-described inhibitory receptor expressed on activated human T cells that, in cooperation with Petition 870260029606, dated 03 / 30 / 2026, page 12 / 366 / 344. Its ligands, Programmed Death Ligand 1 (PD-L1) and Programmed Death Ligand 2 (PD-L2), act as a checkpoint factor limiting T cell-mediated antitumor activity in a variety of human cancers, including melanoma. PD-1 is expressed by TILs and, as such, PD-L1 expression in the tumor microenvironment is inhibitory to cancer disease progression, including, for example, tumor growth.

[005] Consequently, there is a need in the art for new compositions and methods that interfere with the inhibitory effect of the PD-1-PD-L1 interaction, for example, in the context of ACT therapy using TILs. SUMMARY

[006] This disclosure provides proteins, such as antibodies, that include an antigen-binding moiety that specifically binds to Programmed Death Ligand 1 (PD-L1). Nucleic acids encoding the proteins and cells (e.g., genetically modified cytotoxic lymphocytes) containing such nucleic acids are also provided. In some embodiments, a method in question involves reducing the interaction between PD-L1 in a first cell and PD-1 in a second cell. For example, the methods and compositions provided can be used in the treatment of viral infection and cancer, such as in the treatment of solid tumors via ACT or via administration of a protein in question that specifically binds to PD-L1.

[007] The compositions and methods of the present disclosure may enable genetically modified cytotoxic lymphocytes, for example, activated T cells, TILs, and NK cells, to be propagated and introduced as a cell therapy that allows the secretion of a PD-L1 binding protein (e.g., an scFV, a maxibody) onto the genetically modified cytotoxic lymphocytes to be administered to the subject. Thus, the cytotoxic lymphocytes of the present disclosure are Petition 870260029606, dated 03 / 30 / 2026, page 13 / 366 / 344 capable of “releasing” themselves from the inhibitory effect of the PD-1 checkpoint, providing an enhanced anticancer effect in the subject to whom the genetically modified cytotoxic lymphocytes are administered. Specific release-binding proteins (e.g., anti-PD-L1 antibodies) can also be administered to an individual directly, e.g., intravenous (iv) or intratumoral injection.

[008] The disclosure provides a protein that specifically binds to PD-L1 and comprises an antigen-binding moiety comprising: (a) a first polypeptide comprising the 3 CDR amino acid sequences presented in SEQ ID NOs: 2-4, and a second polypeptide comprising the 3 CDR amino acid sequences presented in SEQ ID NOs: 6-8; or (b) a first polypeptide comprising the 3 CDR amino acid sequences presented in SEQ ID NOs: 10-12, and a second polypeptide comprising the 3 CDR amino acid sequences presented in SEQ ID NOs: 14-16, except that each of the three CDR amino acid sequences of the first and / or second polypeptides comprises two or fewer conservative amino acid substitutions with respect to the specified SEQ ID number.

[009] In some embodiments, the antigen-binding portion comprises a first polypeptide comprising the 3 CDR amino acid sequences presented in SEQ ID NOs: 2-4, and a second polypeptide comprising the 3 CDR amino acid sequences presented in SEQ ID NOs: 6-8.

[0010] In some embodiments, the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1, and the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 5.

[0011] In some embodiments, the antigen-binding portion comprises a first polypeptide comprising the 3 sequences of Petition 870260029606, dated 30 / 03 / 2026, p. 14 / 366 / 344 CDR amino acids shown in SEQ ID NOs: 10-12, and a second polypeptide comprising the 3 CDR amino acid sequences shown in SEQ ID NOs: 14-16.

[0012] In some embodiments, the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 9, and the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 13.

[0013] In some embodiments, the first polypeptide is a light chain, and the second polypeptide is a heavy chain.

[0014] In some embodiments, the protein that specifically binds to PD-L1 is a single-chain antibody (scFv), and the first and second polypeptides are fused directly or via a ligand to each other. In some embodiments, scFv comprises the amino acid sequence shown in SEQ ID NO: 17 or SEQ ID NO: 19.

[0015] In some embodiments, the protein that specifically binds to PD-L1 is a maxibody comprising an immunoglobulin Fc domain fused directly or via a ligand to the antigen-binding moiety. In some embodiments, the immunoglobulin Fc domain is an IgG1 Fc domain. In some embodiments, the protein comprises the amino acid sequence shown in SEQ ID NO: 18 or SEQ ID NO: 20. In some embodiments, the immunoglobulin Fc domain is an IgG4 Fc domain.

[0016] In some embodiments, the protein that binds specifically to PD-L1 is a humanized antibody.

[0017] This disclosure also provides a nucleic acid comprising a nucleotide sequence encoding the protein that specifically binds to PD-L1, as disclosed herein. In some embodiments, the nucleic acid comprises a promoter that is operably linked to the nucleotide sequence encoding the protein. In some Petition 870260029606, dated 03 / 30 / 2026, page 15 / 366 / 344 modalities, the prosecutor is a constitutive prosecutor. In some modalities, the prosecutor is an inducible prosecutor.

[0018] This disclosure also provides a cell comprising the nucleic acid encoding the protein that specifically binds to PD-L1. In some embodiments, the nucleic acid is integrated into the cell's genome. In some embodiments, the cell is a cytotoxic lymphocyte genetically modified to express and secrete the protein. In some embodiments, the cytotoxic lymphocyte is a T cell. In some embodiments, the T cell is a CD8+ T cell. In some embodiments, the T cell is a CD4+ helper T cell. In some embodiments, the T cell is derived from peripheral blood. In some embodiments, the cytotoxic lymphocyte is a natural killer (NK) cell. In some embodiments, the NK cell is derived from peripheral blood.

[0019] In some modalities, the cytotoxic lymphocyte is a tumor-infiltrating lymphocyte (TIL) derived from a subject's tumor.

[0020] In some forms, the TIL comprises a specific receptor for a tumor antigen.

[0021] In some modalities, the cytotoxic lymphocyte exhibits an increased level of expression of one or more activation antigens compared to a naive T cell. In some modalities, the one or more activation antigens are selected from CD25, CD26, CD27, CD28, CD38, CD40L, CD69, CD134, CD137, BTLA, PD-1, HVEM, LIGHT, and HLA-DR.

[0022] In some forms, the cytotoxic lymphocyte comprises a T cell receptor specific to a tumor-associated antigen.

[0023] This disclosure also provides a method comprising: genetically modifying a cytotoxic lymphocyte isolated from a subject's tumor by introducing into the cytotoxic lymphocyte nucleic acid encoding a protein that specifically binds to PD-L1, wherein the genetically modified cytotoxic lymphocyte expresses and secretes the protein Petition 870260029606, dated 03 / 30 / 2026, page 16 / 366 / 344, which specifically links to PD-L1; expanding the genetically modified cytotoxic lymphocyte to generate a population of genetically modified cytotoxic lymphocytes; and administering the population of genetically modified cytotoxic lymphocytes to the subject to treat the tumor.

[0024] In some embodiments, the genetically modified cytotoxic lymphocyte constitutively expresses the protein that specifically binds to PD-L1. In some embodiments, the genetically modified cytotoxic lymphocyte inducibly expresses the protein that specifically binds to PD-L1. In some embodiments, the nucleic acid integrates into the cytotoxic lymphocyte genome.

[0025] In some modalities, the cytotoxic lymphocyte is a T cell. In some modalities, the T cell is a CD8+ T cell. In some modalities, the T cell is a CD4+ helper T cell. In some modalities, the cytotoxic lymphocyte is a natural killer (NK) cell.

[0026] In some embodiments, the genetically modified cytotoxic lymphocyte comprises a specific receptor for a tumor antigen.

[0027] In some forms, the method involves isolating the cytotoxic lymphocyte from the subject before genetic modification.

[0028] In some embodiments of the method, the protein that specifically binds to PD-L1 and comprises an antigen-binding moiety comprises: (a) a first polypeptide comprising the 3 CDR amino acid sequences shown in SEQ ID NOs: 2-4, and a second polypeptide comprising the 3 CDR amino acid sequences shown in SEQ ID NOs: 6-8; or (b) a first polypeptide comprising the 3 CDR amino acid sequences shown in SEQ ID NOs: 10-12, and a second polypeptide comprising the 3 CDR amino acid sequences shown in SEQ ID NOs: 14-16, with the exception that each of the three CDR amino acid sequences of the first and / or second polypeptides comprises two or fewer substitutions of Petition 870260029606, dated 03 / 30 / 2026, p. 17 / 366 / 344 amino acid conservative with respect to the specified SEQ ID number.

[0029] In some embodiments of the method, the antigen-binding portion comprises a first polypeptide comprising the 3 CDR amino acid sequences presented in SEQ ID NOs: 2-4, and a second polypeptide comprising the 3 CDR amino acid sequences presented in SEQ ID NOs: 6-8.

[0030] In some embodiments of the method, the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1, and the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 5.

[0031] In some embodiments of the method, the antigen-binding portion comprises a first polypeptide comprising the 3 CDR amino acid sequences presented in SEQ ID NOs: 10-12, and a second polypeptide comprising the 3 CDR amino acid sequences presented in SEQ ID NOs: 14-16.

[0032] In some embodiments of the method, the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 9, and the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 13.

[0033] In some embodiments of the method, the first polypeptide is a light chain, and the second polypeptide is a heavy chain.

[0034] In some embodiments of the method, the protein is a single-chain antibody (scFv) and the first and second polypeptides are fused directly or through a ligand to each other.

[0035] In some embodiments of the method, scFv comprises the amino acid sequence presented in SEQ ID NO: 17 or SEQ ID NO: 19.

[0036] In some embodiments of the method, the protein is a maxibody comprising an Fc domain of immunoglobulin fused directly or via a ligand to the antigen-binding moiety. Petition 870260029606, dated 03 / 30 / 2026, p. 18 / 366 / 344

[0037] In some embodiments of the method, the Fc domain of the immunoglobulin is an Fc domain of IgG1.

[0038] In some embodiments of the method, the protein comprises the amino acid sequence shown in SEQ ID NO: 18 or SEQ ID NO: 20.

[0039] This disclosure also provides a method for manufacturing a genetically modified cytotoxic lymphocyte, the method comprising: genetically modifying a cytotoxic lymphocyte isolated from a subject having or suspected of having cancer by introducing into the cytotoxic lymphocyte the nucleic acid encoding the protein that specifically binds to PD-L1, wherein the genetically modified cytotoxic lymphocyte expresses and secretes the protein that specifically binds to PD-L1. In some embodiments, the genetically modified cytotoxic lymphocyte constitutively expresses the protein that specifically binds to PD-L1. In some embodiments, the genetically modified cytotoxic lymphocyte inducibly expresses the protein that specifically binds to PD-L1.

[0040] In some embodiments, the method involves expanding the cytotoxic lymphocyte in vitro to provide an expanded population of genetically modified cytotoxic lymphocytes.

[0041] In some forms, the method involves isolating the cytotoxic lymphocyte from the subject before genetically modifying it.

[0042] In some embodiments, isolation involves isolating the cytotoxic lymphocyte from a tumor in the subject. In some embodiments, isolation involves isolating the cytotoxic lymphocyte from the subject's peripheral blood.

[0043] In some embodiments of the method, the cytotoxic lymphocyte is a T cell. In some embodiments of the method, the T cell is a CD8+ T cell. In some embodiments of the method, the T cell is a CD4+ helper T cell. In some embodiments of the method, the cytotoxic lymphocyte is a natural killer (NK) cell. Petition 870260029606, dated 03 / 30 / 2026, page 19 / 366 / 344

[0044] In some embodiments of the method, the nucleic acid integrates into the genome of the cytotoxic lymphocyte.

[0045] In some embodiments of the method, the cytotoxic lymphocyte exhibits an increased level of expression of one or more activation antigens compared to a naive T cell. In some embodiments of the method, one or more activation antigens are selected from CD25, CD26, CD27, CD28, CD38, CD40L, CD69, CD134, CD137, BTLA, PD-1, HVEM, LIGHT, and HLA-DR.

[0046] In some embodiments of the method, the genetically modified cytotoxic lymphocyte comprises a specific T-cell receptor for an antigen from a tumor in the subject.

[0047] This disclosure also provides a method for treating an individual who has or is suspected of having cancer, the method comprising: administering the protein that specifically binds to PD-L1 to the individual (e.g., subject or patient, including for example a mammal such as a human being).

[0048] In some embodiments of the method, administration involves introducing into the subject a nucleic acid that encodes the protein that binds specifically to PD-L1.

[0049] In some embodiments of the method, administration involves introducing into the subject a genetically modified cytotoxic lymphocyte that expresses and secretes the protein that binds specifically to PD-L1.

[0050] In some embodiments of the method, the genetically modified cytotoxic lymphocyte constitutively expresses the protein that specifically binds to PD-L1. In some embodiments of the method, the genetically modified cytotoxic lymphocyte inducibly expresses the protein that specifically binds to PD-L1. In some embodiments, the method comprises inducing the expression of the protein that specifically binds to Petition 870260029606, dated 03 / 30 / 2026, p. 20 / 366 / 344 PD-L1.

[0051] In some embodiments of the method, the cytotoxic lymphocyte is a T cell. In some embodiments of the method, the T cell is a CD8+ T cell. In some embodiments of the method, the T cell is a CD4+ helper T cell. In some embodiments of the method, the cytotoxic lymphocyte is a natural killer (NK) cell.

[0052] In some embodiments of the method, the cytotoxic lymphocyte exhibits an increased level of expression of one or more activation antigens compared to a naive T cell. In some embodiments of the method, one or more activation antigens are selected from CD25, CD26, CD27, CD28, CD38, CD40L, CD69, CD134, CD137, BTLA, PD-1, HVEM, LIGHT, and HLA-DR.

[0053] In some embodiments of the method, the genetically modified cytotoxic lymphocyte comprises a specific T-cell receptor for an antigen from a tumor in the subject.

[0054] The present disclosure also provides a method for reducing the interaction between PD-L1 in a first cell and PD-1 in a second cell, the method comprising: contacting PD-L1 in the first cell with the protein that specifically binds to PD-L1.

[0055] In some embodiments of the method, the first and second cells are introduced into an individual, and the contact involves administering the protein that specifically binds to PD-L1. In some embodiments of the method, the introduction involves systemic administration. In some embodiments of the method, the introduction involves local administration. In some embodiments of the method, local administration involves intratumoral administration. In some embodiments of the method, the individual has cancer. In some embodiments of the method, the individual has a solid tumor. BRIEF DESCRIPTION OF THE DRAWINGS Petition 870260029606, dated 03 / 30 / 2026, page 21 / 366 / 344

[0056] The invention can be better understood from the following detailed description when read in conjunction with the accompanying drawings. Included in the drawings are the following figures:

[0057] Figure 1 provides a schematic representation of the lentiviral plasmid used to produce 38A1-Fc, 19H9-Fc, and FMC63-Fc. The anti-PD-L1 maxibodies are encoded downstream of the U3 promoter of the MSCV promoter and upstream of an IRES-eGFP cassette.

[0058] Figure 2 provides a schematic representation of the retroviral plasmid used to produce 38A1-Fc, 19H9-Fc, and FMC63-Fc. The anti-PD-L1 maxibodies are encoded downstream of the U3 promoter from the MSCV promoter and upstream of an IRES-eGFP cassette.

[0059] Figure 3A-3B provides cell-based ELISA data to determine the affinity of 38A1-scFV-Fc and 19H9-scFV-Fc for PD-L1. 293-PD-L1 cells were stained with 19H9-scFV-Fc (panel A) or 38A1-scFV-Fc (panel B). Maxibodies were titrated from 100 nM to 0.01 nM in 293-PDL1, washed, and stained with HRP-labeled human anti-Fcy specific antibody. Binding was determined by optical density at 450 nm following the addition of TMB (3,3',5,5'-tetramethylbenzidine). 12D10-scFV-Fc was used as the negative control.

[0060] Figure 4A-4C provides data showing that 293PD-L1 cells bind anti-PD-L1 maxibodies secreted by Jurkat T cells. Jurkat T cells stably expressing FMC63-scFV-Fc (panel A), 38A1-scFV-Fc (panel B) or 19H9-scFV-Fc (panel C) were co-cultured at a 1:1 ratio for 16 hours. Cells were harvested and stained with a specific anti-human Fcy antibody labeled Alexa 647. Compared with the negative control maxibody (FMC63-scFV-Fc), between a 100-fold and 300-fold increase in mean fluorescence intensity (maxibody binding) was observed for 19H9-scFV-Fc and 38A1-scFV-Fc, respectively. Petition 870260029606, dated 03 / 30 / 2026, page 22 / 366 / 344

[0061] Figure 5A-5D provides data showing that 293PD-L1 cells bind anti-PD-L1 maxibodies secreted by tumor-infiltrating lymphocytes (TILs). The supernatant from TIL cell lines M1034 (panel A, panel B) and M1015 (panel C, panel D) stably expressing FMC63scFV-Fc (panel A, panel C) or 38A1-scFV-Fc (panel B, panel D) were concentrated 10-fold and used to stain 293-PD-L1. Maxibodies were detected using specific anti-human Fcy antibody labeled Alexa 647. Compared to the negative control maxibody (FMC63-scFV-Fc), we observed a greater than 50-fold increase in mean fluorescence intensity (maxibody binding) for 38A1-scFV-Fc.

[0062] Figure 6 provides data showing the ability of anti-PD-L1 maxibodies to limit PD-L1-mediated inhibition of NFAT activity. Jurkat T cells expressing PD1 and firefly luciferase downstream of the NFAT promoter were co-cultured in a 2:1 ratio with CHO cells expressing PD-L1 and a patented T-cell agonist protein (PD1 / PD-L1 Blockade Bioassay Kit, Promega catalog number CS187111) and one of 12D10-scFV-Fc (negative control; gray), 19H9-scFV-Fc (red), 38A1-scFV-Fc (blue) or the positive control PD1-specific antibody EH12.2H7 (Biolegend; green). Maxibodies were titrated from 25 pg / ml to 0.016 pg / ml. Jukat T cell activation (PD-L1 disinhibition) was measured as bioluminescent activity (Relative Luminescent Units; RLU) following the addition of 5'Fluoroluciferin.

[0063] Figure 7 provides sequences of the antigen-binding regions of newly generated 38A1 and 19H9 antibodies, as well as examples of scFV proteins (e.g., scFV and scFV-FC fusions) that include 38A1 or 19H9 antigen-binding regions.

[0064] Figure 8 represents a schematic of an example of an expression vector (e.g., lentivetor) that encodes a promoter. Petition 870260029606, dated 03 / 30 / 2026, p. 23 / 366 / 344 inducible.

[0065] Figure 9 represents a schematic of an example of an expression vector (e.g., lentivetor) that encodes an inducible promoter.

[0066] Figure 10 provides the empty vector sequence for the pLEV vector used as an exemplary vector in the present methods. pLV430G (Lentiviral Vector) (SEQ ID NO: 35) (A) and pCIGO-VSV.G (VSVG) (SEQ ID NO: 36) (B).

[0067] Figure 11A-11B provides the nucleotide sequence of the complete vector for pLV4301G PDLV scFV 38A1 (SEQ NO: 37) (A) and pLV4301G PDLV scFV 19H9 (SEQ ID NO: 38) (B).

[0068] Figure 12 provides data showing that 19H9 exhibits greater secretory capacity. A comparison of the secretory capacity of Jurkat cells overexpressing ScFV anti-PD-L1 clone 19H9 versus 38A1 is provided. The supernatant from Jurkat cells overexpressing ScFV anti-PD-L1 clone 19H9 and 38A1 were harvested and concentrated for the IgG ELISA assay to determine the concentration of ScFV anti-PD-L1. It was found that Jurkat cells clone 19H9 had greater secretory capacity when compared to 38A1 (9.82 versus 6.75 pg / cell).

[0069] Figure 13A-13B provides data showing that 38A1 exhibits greater binding capacity in Jurkat cells that overexpress PD-L1. The binding affinity of ScFV anti-PD-L1 clone 19H9 and 38A1 using EL4 PD-L1 cells was examined. EL4 PD-L1 cells were incubated with ScFV anti-PD-L1 clone 19H9 or 38A1 at concentrations of 1, 3, 10, 30, 100, and 300 ng / ml, and stained with Amcyan and goat anti-human FITC. Cells were washed with FACs buffer and analyzed by flow cytometry. Clone 38A1 exhibited greater binding capacity in Jurkat cells that overexpress PD-L1 in both percentages of PD-L1 positive cells (a) and Mean Fluorescence Intensity (MFI) (B). Petition 870260029606, dated 03 / 30 / 2026, page 24 / 366 / 344

[0070] Figure 14A-14B provides data showing that 38A1 exhibits greater binding capacity in melanoma tumor cells. A comparison of the binding affinity of ScFV anti-PD-L1 clone 19H9 and 38A1 using EL4 PD-L1 cells is provided. EL4 PD-L1 cells were incubated with ScFV anti-PD-L1 clone 19H9 or 38A1 at concentrations of 1, 3, 10, 30, 100, and 300 ng / ml, and stained with Amcyan and goat anti-human FITC. Cells were washed with FACs buffer and analyzed by flow cytometry. Clone 38A1 exhibited greater binding capacity in Jurkat cells overexpressing PD-L1 in both percentages of PD-L1 positive cells (A) and Mean Fluorescence Intensity (MFI) (B). To validate the binding of anti-PD-L1 ScFV in tumor cells, three melanoma tumor cells were treated with IFN-gamma (100 ng / ml) to enhance PD-L1 expression.After three days, cells were harvested with cell dissociation buffer, incubated with ScFV anti-PD-L1 clone 19H9 or 38A1 at concentrations of 100 ng / ml, and stained with goat anti-human FITC. Cells were washed with FACs buffer and analyzed by flow cytometry. We found that clone 38A1 exhibited higher binding affinity in both PD-L1 and MFI positive cell percentages. Overall, clone 38A1 has higher binding affinity but slightly less secretory capacity when compared to clone 19H9.

[0071] Figures 15A-15B provide data showing that 38A1 exhibits greater biological function than 19H9. To further determine the biological function of two anti-PD-L1 ScFV clones (19H9 and 38A1), a PD-L1 blocking assay was conducted, which can be used to determine the potency of anti-PD-1 or PD-L1 antibodies that block the interaction between PD-1 and PD-L1. The assay consists of two genetically engineered cell lines: PD-1 effector cells (jurkat T cells stably expressing human PD-1 and NFAT-induced luciferase) and PD-L1 aAPC / CHO-K1 cells stably expressing human PD-L1. Petition 870260029606, dated 03 / 30 / 2026, page 25 / 366 / 344 with one of the cognate TCRs that activate the cell surface protein. When two cell types were co-cultured, the interplay of PD-1 and PD-L1 inhibited TCR signaling and decreased luciferase activity. The addition of anti-PD-1 or PD-L1 blocking antibody helped to release the inhibitory signal, resulting in enhanced TCR signaling and NFAT-mediated luciferase activity. The luciferase signal (RLU) was found to be higher when blocked with anti-PD-L1 compared to anti-PD-L1, suggesting that blocking PD-L1 appears to be more effective than blocking PD-L1 in this context (A). As expected, ScFV anti-PD-L1 clone 38A1, which previously showed higher binding affinity, provided greater biological function due to the highly increased luciferase signal in both the purified (P) and non-purified (NP) ScFV scenarios (B).

[0072] Figure 16 provides the vector maps for pLV4301G PDLV scFV 38A1 (A) and pLV4301G PDLV scFV 19H9 (B).

[0073] Figure 17 provides examples of IgG1 (SEQ ID NO: 39), IgG2 (SEQ ID NO: 40), IgG3 (SEQ ID NO: 41), and IgG4 (SEQ ID NO: 42) sequences. DETAILED DESCRIPTION

[0074] This disclosure provides proteins, such as antibodies, that include an antigen-binding moiety that specifically binds to Programmed Death Ligand 1 (PD-L1). Nucleic acids encoding the proteins and cells (e.g., genetically modified cytotoxic lymphocytes) containing such nucleic acids are also provided. In some embodiments, a method in question involves reducing the interaction between PD-L1 in a first cell and PD-1 in a second cell. For example, the methods and compositions provided can be used in the treatment of viral infections and cancer, such as in the treatment of solid tumors via ACT or via administration of a protein in question that specifically binds to PD-L1. Petition 870260029606, dated 03 / 30 / 2026, p. 26 / 366 / 344

[0075] The compositions and methods of the present disclosure provide genetically modified cytotoxic lymphocytes, for example, activated T cells, TILs, and NK cells, which can be propagated and infused as a cell therapy, resulting in the secretion of a PD-L1 binding protein (e.g., an scFV, a maxibody, and the like) onto the genetically modified cytotoxic lymphocytes infused into the subject. In this way, the cytotoxic lymphocytes of the present disclosure are able to “release” themselves from the inhibitory effect of the PD-1 checkpoint, providing an enhanced anticancer effect. The specific binding proteins of the disclosure (e.g., anti-PD-L1 antibodies) can also be administered to an individual directly, for example, by intravenous (iv) or intratumoral injection.

[0076] Before the present invention is described in more detail, it should be understood that this invention is not limited to the particular embodiments described, and as such may, of course, vary. It should also be understood that the terminology used herein is for the purpose of describing only particular embodiments, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

[0077] When a range of values ​​is provided, it is understood that each intermediate value, up to the tenth of a unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limits of this range is also specifically disclosed. Each smaller range between any established value or intermediate value in an established range and any other established or intermediate value in which the established range is encompassed is within the invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range, and each range where each, none, or both of the limits are included in the smaller ranges is also encompassed within the invention. Petition 870260029606, dated 30 / 03 / 2026, p. 27 / 366 / 344 subject to any limit specifically excluded in the established range. Where the established range includes one or both of the limits, ranges excluding each or both of these included limits are also included in the invention.

[0078] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as usually understood by a person with ordinary professional knowledge in the art to which this invention pertains. Such terms are found defined and used in context in various standard references, illustratively including J. Sambrook and DW Russell, Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory Press; 4th Ed., 2012; FM Ausubel, Ed., Short Protocols in Molecular Biology, Current Protocols; 5th Ed., 2002; B. Alberts et al., Molecular Biology of the Cell, 4th Ed., Garland, 2002; DL Nelson and MM Cox, Lehninger's Principles of Biochemistry, 4th Ed., WHFreeman & Company, 2004; and Herdewijn, P. (Ed.), Oligonucleotide Synthesis: Methods and Applications, Methods in Molecular Biology, Humana Press, 2004. Although any methods and materials similar or equivalent to those described herein may be used in the practice or testing of the present invention, preferred methods and materials are described.

[0079] As used herein, each of the following terms has the meaning associated with it in this section.

[0080] The articles “um” and “uma” are used here to refer to one or more than one (i.e., at least one) of the grammatical object of the article. For example, “um elemento” means one element or more than one element.

[0081] “Approximately” as used herein when referring to a measurable value such as a quantity, a time duration, and the like, is intended to encompass variations of ±20% or ±10%, more preferably ±5%, even more preferably ±1% and, even more preferably, ±0.1% of the specified value, insofar as such variations are appropriate for carrying out the Petition 870260029606, dated 03 / 30 / 2026, page 28 / 366 / 344 methods disclosed.

[0082] The term “antitumor effect” as used herein refers to a biological effect that may be manifested by a decrease in tumor volume, a decrease in the number of tumor cells, a decrease in the number of metastases, an increase in life expectancy, or improvement of various physiological symptoms associated with the cancerous condition. An “antitumor effect” may also be manifested by the ability of the disclosed compositions and methods to prevent tumor occurrence in the first place.

[0083] The term “antibody” is used in the broadest sense and includes, for example, an intact immunoglobulin or an antigen-binding portion thereof that competes with the intact antibody for specific binding, unless otherwise specified. Antigen-binding portions can be produced by recombinant DNA techniques or by enzymatic or chemical cleavage of intact antibodies. Antigen-binding portions include Fab, Fab', F(ab')2, Fd, Fv, and domain antibodies (dAbs), and complementarity-determining region (CDR) fragments, single-chain antibodies (single-chain variable domain fragment; scFv), diabodies, triabodies, tetrabodies, and polypeptides containing at least one portion of an immunoglobulin sufficient to confer specific antigen binding to the polypeptide.The antibody includes a human antibody, a humanized antibody, a chimeric antibody, a monoclonal antibody, a polyclonal antibody, a recombinant antibody, an antigen-binding antibody fragment, a single-chain antibody, a maxibody (scFv fused by a ligand or direct binding to an Fc or an Fc fragment), a diabody, a triabody, a tetrabody, a Fab fragment, an F(fa')x fragment, a domain antibody, an IgD antibody, an IgE antibody, and an IgM antibody, and an IgG1 antibody, and an IgG2 antibody, and an IgG3 antibody, and an IgG4 antibody, and an IgG4 antibody having at least one mutation in the hinge region that... Petition 870260029606, dated 30 / 03 / 2026, p. 29 / 366 / 344 alleviates a tendency towards intra-chain disulfide H bonds.

[0084] A “Fab fragment” is a monovalent fragment having the VL, VH, CL, and CH1 domains; an F(ab')2 fragment is a bivalent fragment having two Fab fragments linked by a disulfide bridge in the hinge region; an Fd fragment has the VH and CH1 domains; an Fv fragment has the VL and VH domains of a single arm of an antibody; and a dAb fragment has a VH domain, a VL domain, or an antigen-binding fragment of a VH or VL domain.

[0085] A “single-chain antibody” (scFv) is an antibody in which a VL and a VH region are fused directly or joined via a linker (e.g., a synthetic sequence of amino acid residues) to form a continuous protein chain where the linker is long enough to allow the protein chain to fold back on itself and form a monovalent antigen-binding site (see, for example, Bird et al., 1988, Science 242: 423-26 and Huston et al., 1988, Proc. Diabodies are bivalent antibodies comprising two polypeptide chains, wherein each polypeptide chain comprises VH and VL domains joined by a linker that is too short to pair between two domains on the same chain, thus allowing each domain to pair with a complementary domain on another polypeptide chain (see, for example, Holliger et al., 1993, Proc. Natl. Acad. Sci. USA 90: 6444-48, and Poljak et al.(1994, Structure 2: 1121-23). ​​If the two polypeptide chains of a diabody are identical, then a diabody resulting from their pairing will have two identical antigen-binding sites. Polypeptide chains having different sequences can be used to fabricate a diabody with two different antigen-binding sites. Similarly, tribodies and tetrabodies are antibodies comprising three and four polypeptide chains, respectively, and forming three and four antigen-binding sites. Petition 870260029606, dated 03 / 30 / 2026, p. 30 / 366 / 344 antigen, respectively, which may be the same or different.

[0086] The complementarity-determining regions (CDRs) and scaffold region (FR) of a given antibody can be identified using the system described by Kabat et al. in Sequences of Proteins of Immunological Interest, 5th Ed., US Dept. of Health and Human Services, PHS, NIH, NIH Publication no. 91-3242, 1991. One or more CDRs can be incorporated into a molecule covalently or non-covalently to make it an antigen-binding protein. An antigen-binding protein can incorporate the CDR(s) as part of a larger polypeptide chain, can covalently link the CDR(s) to another polypeptide chain, or can incorporate the CDR(s) non-covalently. CDRs allow the antigen-binding protein to bind specifically to a particular antigen of interest.

[0087] The term “human antibody” includes all antibodies that have one or more variable and constant regions derived from human immunoglobulin sequences. In one embodiment, all of the variable and constant domains are derived from human immunoglobulin sequences (a fully human antibody). Human antibodies can be prepared in a variety of ways, including immunizing a mouse that is genetically modified to express human antibodies. One can engineer mouse strains deficient in producing mouse antibodies with large fragments of human Ig sites in the expectation that such mice would produce human antibodies in the absence of mouse antibodies. Large human Ig fragments can preserve the large diversity of variable genes as well as the appropriate regulation of antibody production and expression.By exploring the mouse mechanism for antibody diversification and selection, and the lack of tolerance for human proteins, the repertoire of human antibodies reproduced in these mouse strains may produce antibodies. Petition 870260029606, dated 03 / 30 / 2026, page 31 / 366 / 344, high-affinity fully human antibodies against any antigen of interest, including human antigens. Using hybridoma technology, antigen-specific human MAbs with the desired specificity can be produced and selected. Human antibodies can also be prepared by mining human antibody libraries expressed on phages, phagomids, ribosomes, or other particles.

[0088] A “humanized antibody” has a sequence that differs from the sequence of an antibody derived from a non-human species by one or more amino acid substitutions, deletions, and / or additions, such that the humanized antibody is less likely to induce an immune response, and / or induces a less severe immune response, when compared with the non-human species antibody when administered to a human subject. In one embodiment, certain amino acids in the backbone and constant domains of the heavy and / or light chains of the non-human species antibody are mutated to produce the humanized antibody. In another embodiment, the constant domain(s) of a human antibody is / are fused to the variable domain(s) of a non-human species.In another embodiment, one or more amino acid residues in one or more CDR sequences of a non-human antibody are changed to reduce the likelihood of immunogenicity of the non-human antibody when administered to a human subject, wherein the changed amino acid residues are not critical for the immunospecific binding of the antibody to its antigen, or the changes to the amino acid sequence that are manufactured are conservative changes, such that the binding of the humanized antibody to the antigen is not significantly worse than the binding of the non-human antibody to the antigen. Examples of methods for manufacturing humanized antibodies can be found in U.S. Pat. Nos. 6,054,297, 5,886,152, and 5,877,293, the disclosures of each of which are incorporated herein by reference. Petition 870260029606, dated 03 / 30 / 2026, p. 32 / 366 / 344

[0089] The term “chimeric antibody” refers to an antibody that contains one or more regions of one antibody and one or more regions of one or more other antibodies. A “CDR-grafted antibody” is an antibody comprising one or more CDRs derived from an antibody of a particular species or isotype and the scaffold of another antibody of the same or different species or isotype.

[0090] The term “Kassoc” or “Ka”, as used herein, is intended to refer to the association rate of a particular antibody-antigen interaction, whereas the term “Kdis” or “Kd”, as used herein, is intended to refer to the dissociation rate of a particular antibody-antigen interaction. The term “KD”, as used herein, is intended to refer to the dissociation constant, which is obtained from the ratio of Kd to Ka (i.e., Kd / Ka) and is expressed as a molar concentration (M). KD values ​​for antibodies can be determined using well-established methods in the art. In some embodiments, the method for determining the Kd of an antibody is using surface plasmon resonance, for example, using a biosensor system such as a Biacore® system.

[0091] As used herein, the term “high affinity” for an IgG antibody refers to an antibody having a Kd of 10⁻⁸ M or less, in some embodiments, 10⁻⁹ M or less, and in some embodiments, 10⁻¹⁰ M or less for a target antigen. However, “high affinity” binding may vary for other antibody isotypes. For example, “high affinity” binding for an IgM isotype refers to an antibody having a Kd of 10⁻⁷ M or less, in some embodiments, 10⁻⁸ M or less, and in some embodiments, 10⁻⁹ M or less.

[0092] The term “constitutive” includes a state in which a gene product is produced in a living cell under most or all of the cell’s physiological conditions.

[0093] A “coding region” of a gene includes the residues of Petition 870260029606, dated 03 / 30 / 2026, page 33 / 366 / 344 nucleotide of the coding strand of the gene and the nucleotides of the non-coding strand of the gene that are homologous with or complementary, respectively, to the coding region of an mRNA molecule that is produced by transcription of the gene. A “coding region” of an mRNA molecule also includes the nucleotide residues of the mRNA molecule that are combined with an anticodon region of a transfer RNA molecule during translation of the mRNA molecule or that encode a stop codon. The coding region may thus include nucleotide residues comprising codons for amino acid residues that are not present in the mature protein encoded by the mRNA molecule (e.g., amino acid residues in a protein export signal sequence).

[0094] By “tumor-infiltrating lymphocytes” or “TILs” is meant a population of cells originally obtained as white blood cells that have left a subject’s bloodstream and migrated into a tumor. TILs include, but are not limited to, cytotoxic CD8+ T cells (lymphocytes), CD4+ Th1 and Th17 T cells, natural killer cells, dendritic cells, and M1 macrophages. TILs include both primary and secondary TILs. “Primary TILs” are those obtained from patient tissue samples as outlined herein (sometimes referred to as “freshly harvested”), and “secondary TILs” are any TIL cell populations that have been expanded or proliferated as disclosed herein, including, but not limited to, bulky TILs and expanded TILs (“REP TILs”) as disclosed herein.

[0095] TILs can generally be defined biochemically, using cell surface markers, or functionally, by their ability to infiltrate tumors and effect treatment. TILs can generally be categorized by the expression of one or more of the following biomarkers: CD4, CD8, TCR αβ, CD27, CD28, CD56, CCR7, CD45Ra, Petition 870260029606, dated 03 / 30 / 2026, page 34 / 366 / 344 CD95, PD-1, and CD25. Additionally and alternatively, TILs can be functionally defined by their ability to infiltrate solid tumors upon reintroduction into a patient.

[0096] The term “cytotoxic lymphocyte” includes cytotoxic T cells (CTLs) (including cytotoxic CD8+ T lymphocytes and CD4+ helper T lymphocytes), natural killer (NK) cells, and natural killer (NK) cells. Cytotoxic lymphocytes may include, for example, peripheral blood-derived T cells that are positive for αβ TCR or positive for γδ TCR activated by tumor-associated antigens and / or transduced with tumor-specific chimeric antigen receptors or T cell receptors, and tumor-infiltrating lymphocytes (TILs). Cytotoxic lymphocytes generally kill cancerous cells, cells that are infected (particularly with viruses), or cells that are otherwise damaged or defective. A cytotoxic lymphocyte can also be referred to as a cytotoxic T cell, TC, cytotoxic T lymphocyte, CTL, killer T cell, cytolytic T cell, CD8+ T cell, or killer T cell; it is a T lymphocyte (a type of white blood cell).

[0097] The terms “fragmentation”, “fragment”, and “fragmented”, as used herein to describe processes for breaking up a tumor, include methods of mechanical fragmentation such as crushing, cutting, splitting, and morcellation of tumor tissue as well as any other method for breaking up the physical structure of tumor tissue.

[0098] The term “in vivo” refers to an event that occurs in the body of a subject.

[0099] The term “in vitro” refers to an event that occurs outside the body of a subject. In vitro assays encompass cell-based assays in which live or dead cells are used and may also encompass a cell-free assay in which no intact cells are used.

[00100] The term “anti-CD3 antibody” refers to an antibody or Petition 870260029606, dated 30 / 03 / 2026, p. 35 / 366 / 344 variant thereof, for example, a monoclonal antibody and including human, humanized, chimeric or murine antibodies that are directed against the CD3 receptor on the T cell antigen receptor of mature T cells. Anti-CD3 antibodies include OKT-3, also known as muromonab. Other anti-CD3 antibodies include, for example, otelixizumab, teplizumab, and visilizumab.

[00101] The term “OKT-3” (also referred to herein as “OKT3”) refers to a monoclonal antibody or biosimilar or variant thereof, including human, humanized, chimeric, or murine antibodies, directed against the CD3 receptor on the T cell antigen receptor of mature T cells, and includes commercially available forms such as OKT-3 (30 ng / mL, MACS GMP pure CD3, Miltenyi Biotech, Inc., San Diego, CA, USA) and muromonab or variants, conservative amino acid substitutions, glycoforms, or biosimilars thereof. The amino acid sequences of the heavy and light chains of muromonab are given in Table 1 (SEQ ID NO: 27 and SEQ ID NO: 28). A hybridoma capable of producing OKT-3 is deposited with the American Type Culture Collection and assigned the accession number ATCC CRL 8001. A hybridoma capable of producing OKT-3 is also deposited with the European Collection of Authenticated Cell Cultures (ECACC) and assigned the catalog number 86022706. TABLE 1. Amino acid sequences of muromonab. Identifier_____Sequence (One-Letter Amino Acid Symbols) SEQ ID NO' 27 Qvqlqqsgae larpgasvkm sckasgytft rytmhwvkqr pgqglewigy inpsrgytny, . \ , NQKFKDKATL TTDKSSSTAY MQLSSLTSED SAVYYCARYY DDHYCLDYWG QGTTLTVSSA Cadeia peSada deKTTAPSVYPL APVCGGTTGS SVTLGCLVKG YFPEPVTLTW NSGSLSSGVH TFPAVLQSDL Muromonab YTLSSSVTVT sstwpsqsit cnvahpasst kvdkkieprp kscdkthtcp pcpapellgg PSVFLFPPKP KDTLMISRTP EVTCVVVDVS HEDPEVKFNW YVDGVEVHNA KTKPREEQYN STYRVVSVLT VLHQDWLNGK EYKCKVSNKA LPAPIEKTIS KAKGQPREPQ VYTLPPSRDE LTKNQVSLTC LVKGFYPSDI AVEWESNGQP ENNYKTTPPV LDSDGSFFLY SKLTVDKSRW QQGNVFSCSV MHEALHNHYT QKSLSLSPGK 60 120 180 240 300 360 420 450 SEQ ID NO: 28 qivltqspai msaspgekvt mtcsasssvs ywwyqqksg tspkrwiydt sklasgvpah j . 1 ' J FRGSGSGTSY SLTISGMEAE DAATYYCQQW SSNPFTFGSG TKLEINRADT APTVSIFPPS ca.deia. leve de caneta xeve ^eSEQLTSGGAS VVCFLNNFYP KDINVKWKID GSERQNGVLN SWTDQDSKDS TYSMSSTLTL Muromonab tkdeyerhns ytceathkts tspivksfnr nec 60 120 180 213

[00102] The term “IL-2” (also referred to here as “IL2”) refers to the T-cell growth factor known as interleukin-2, and includes all forms of IL-2 including human and mammalian forms, Petition 870260029606, dated 30 / 03 / 2026, p. 36 / 366 / 344 conservative amino acid substitutions, glycoforms, biosimilars, and variants thereof. IL-2 is described, for example, in Nelson, J. Immunol. 2004, 172, 3983-88 and Malek, Annu. Rev. Immunol. 2008, 26, 453-79, disclosures of which are incorporated herein by reference. The amino acid sequence of recombinant human IL-2 suitable for use in the invention is given in Table 2 (SEQ ID NO: 3). For example, the term IL-2 encompasses human, recombinant forms of IL-2 such as aldesleukin (PROLEUCIN, commercially available from multiple suppliers in 22 million IU per single-use vial), as well as the commercially supplied recombinant IL-2 form from CellGenix, Inc., Portsmouth, NH, USA (CELLGRO GMP) or ProSpec-Tany TechnoGene Ltd., East Brunswick, NJ, USA (Cat. No. CYT-209-b) and other commercial equivalents from other suppliers.Aldesleucine (des-alanyl-1, serine-125 human IL-2) is a recombinant human non-glycosylated form of IL-2 with a molecular weight of approximately 15 kDa. The amino acid sequence of aldesleucine suitable for use in the invention is given in Table 2 (SEQ ID NO: 30). The term IL-2 also encompasses pegylated forms of IL-2, as described herein, including the pegylated IL-2 prodrug NKTR-214, available from Nektar Therapeutics, South San Francisco, CA, USA. NKTR214 and pegylated IL-2 suitable for use in the invention are described in US Patent Application Publication No. US 2014 / 0328791 A1 and International Patent Application Publication No. WO 2012 / 065086 A1, disclosures of which are incorporated herein by reference. Alternative forms of conjugated IL-2 suitable for use in the invention are described in U.S. Patents Nos. 4,766,106, 5,206,344, 5,089,261 and 4,902,502, disclosures of which are incorporated herein by reference.Suitable IL-2 formulations for use in the invention are described in U.S. Patent No. 6,706,289, the disclosure of which is incorporated herein by reference.

[00103] As used herein, interleukins include IL-2, IL-4, IL-7, IL-870260029606, dated 03 / 30 / 2026, p. 37 / 366 / 344 15, and IL-21. Exemplary sequences for these interleukins are provided in Table 2 below. TABLE 2. Amino acid sequences of interleukins. Sequence Identifier (Letter Aminoacid Symbol) SEQ ID NO: 29 MAPTSSSTKK TQLQLEHLLL DLQMILNGIN NYKNPKLTRM LTFKFYMPKK ATELKHLQCL 60 IL-2 human recombinante (rhIL-2) EEELKPLEEV RWITFCQSII LNLAQSKNFH STLT LRPRDLISNI NVIVLELKGS ETTFMCEYAD ETATIVEFLN 120 134 SEQ ID NO: 30 PTSSSTKKTQ LQLEHLLLDL QMILNGINNY KNPKLTRMLT FKFYMPKKAT ELKHLQCLEE 60 Aldesleucine (Proleucine®) ELKPLEEVLN ITFSQSIIST LAQSKNFHLR LT PRDLISNINV IVLELKGSET TFMCEYADET ATIVEFLNRW 120 132 SEQ ID NO: 31 MHKCDITLQE IIKTLNSLTE QKTLCTELTV TDIFAASKNT TEKETFCRAA TVLRQFYSHH 60 IL-4 recombinante humana (rhIL-4) EKDTRCLGAT MREKYSKCSS AQQFHRHKQL IRFLKRLDRN LWGLAGLNSC PVKEANQSTL ENFLERLKTI 120 130 SEQ ID NO: 32 MDCDIEGKDG KQYESVLMVS IDQLLDSMKE IGSNCLNNEF NFFKRHICDA NKEGMFLFRA 60 IL-7 recombinante humana (rhIL-7) ARKLRQFLKM KEQKKLNDLC NSTGDFDLHL FLKRLLQEIK LKVSEGTTIL TCWNKILMGT LNCTGQVKGR KEH KPAALGEAQP TKSLEENKSL 120 153 SEQ ID NO: 33 MNWVNVISDL KKIEDLIQSM HIDATLYTES DVHPSCKVTA MKCFLLELQV ISLESGDASI 60 IL-15 recombinanteHDTVENLIIL ANNSLSSNGN VTESGCKECE ELEEKNIKEF LQSFVHIVQM FINTS 115 humana (rhIL-15) SEQ ID NO: 34 MQDRHMIRMR QLIDIVDQLK NYVNDLVPEF LPAPEDVETN CEWSAFSCFQ KAQLKSANTG 60 IL-21 recombinante humana (rhIL-21) NNERIINVSI HLSSRTHGSE KKLKRKPPST DS NAGRRQKHRL TCPSCDSYEK KPPKEFLERF KSLLQKMIHQ 120 132

[00104] The term “IL-4” (also referred to here as “IL4”) refers to the cytokine known as interleukin 4, which is produced by Th2 T cells and by eosinophils, basophils, and mastoids. IL-4 regulates the differentiation of naive helper T cells (Th0 cells) into Th2 T cells. Steinke and Borish, Respir. Res. 2001, 2, 66-70. Upon activation by IL-4, Th2 T cells subsequently produce additional IL-4 in a positive feedback loop. IL-4 also stimulates B cell proliferation and MHC class II expression, and induces class switching for IgE and IgG1 expression from B cells. Suitable recombinant human IL-4 for use in the invention is commercially available from multiple suppliers, including ProSpec-Tany TechnoGene Ltd., East Brunswick, NJ, USA (Cat. No. CYT211) and ThermoFisher Scientific, Inc., Waltham, MA, USA (recombinant human IL-15 protein, Cat. No. Gibco CTP0043).The amino acid sequence of recombinant human IL-4 suitable for use in the invention is given in Table 2 (SEQ ID NO: 31).

[00105] The term “IL-7” (also referred to here as “IL7”) refers to Petition 870260029606, dated 03 / 30 / 2026, pp. 38 / 366 / 344, a glycosylated tissue-derived cytokine known as interleukin 7, which can be obtained from stromal and epithelial cells, as well as from dendritic cells. Fry and Mackall, Blood 2002, 99, 3892-904. IL-7 can stimulate T cell development. IL-7 binds to the IL-7 receptor, a heterodimer consisting of IL-7 receptor alpha and receptor gamma chains, which in turn sends a series of signals important for T cell development within the thymus and survival within the periphery. Recombinant human IL-4 suitable for use in the invention is commercially available from multiple suppliers, including ProSpecTany TechnoGene Ltd., East Brunswick, NJ, USA (Cat. No. CYT-254) and ThermoFisher Scientific, Inc., Waltham, MA, USA (recombinant human IL-15 protein, Cat. No. Gibco PHC0071).The amino acid sequence of recombinant human IL-7 suitable for use in the invention is given in Table 2 (SEQ ID NO: 32).

[00106] The term “IL-15” (also referred to herein as “IL15”) refers to the T-cell growth factor known as interleukin-15, and includes all forms of IL-2 including human and mammalian forms, conservative amino acid substitutions, glycoforms, biosimilars, and variants thereof. IL-15 is described, for example, in Fehniger and Caligiuri, Blood 2001, 97, 14-32, the publication of which is incorporated herein by reference. IL-15 shares β and γ signaling receptor subunits with IL-2. Recombinant human IL-15 is a single, non-glycosylated polypeptide chain containing 114 amino acids (and an N-terminal methionine) with a molecular mass of 12.8 kDa. Recombinant human IL-15 is commercially available from several suppliers, including ProSpecTany TechnoGene Ltd., East Brunswick, NJ, USA (Cat. No. CYT-230-b) and ThermoFisher Scientific, Inc., Waltham, MA, USA (recombinant human IL-15 protein, Cat. No. 34-8159-82).The amino acid sequence of recombinant human IL-15 suitable for use in the invention is given in Figure 1. Petition 870260029606, dated 03 / 30 / 2026, p. 39 / 366 / 344 Table 2 (SEQ ID NO: 33).

[00107] The term “IL-21” (also referred to herein as “IL21”) refers to the pleiotropic cytokine protein known as interleukin-21, and includes all forms of IL-21 including human and mammalian forms, conservative amino acid substitutions, glycoforms, biosimilars, and variants thereof. IL-21 is described, for example, in Spolski and Leonard, Nat. Rev. Drug. Disc. 2014, 13, 379-95, the publication of which is incorporated herein by reference. IL-21 is primarily produced by human natural killer T cells and activated CD4+ T cells. Recombinant human IL-21 is a single, non-glycosylated polypeptide chain containing 132 amino acids with a molecular mass of 15.4 kDa. Recombinant human IL-21 is commercially available from multiple suppliers, including ProSpec-Tany TechnoGene Ltd., East Brunswick, NJ, USA (Cat. No. CYT-408-b) and ThermoFisher Scientific, Inc., Waltham, MA, USA (recombinant human IL-21 protein, Cat. No. 14-8219-80).The amino acid sequence of recombinant human IL-21 suitable for use in the invention is given in Table 2 (SEQ ID NO: 34).

[00108] A “disease” includes a state of health in an animal in which the animal cannot maintain homeostasis, and in which if the disease is not improved then the animal’s health continues to deteriorate.

[00109] Conversely, a “disorder” in an animal includes a state of health in which the animal is able to maintain homeostasis, but in which the animal’s state of health is less favorable than it would be in the absence of the disorder. Left untreated, a disorder does not necessarily cause a further decrease in the animal’s state of health.

[00110] A disease or disorder is “relieved” if the severity of a symptom of the disease or disorder, the frequency with which such a symptom is experienced by a patient, or both, are reduced.

[00111] With respect to inventive methods, the term “tumor” or Petition 870260029606, dated 03 / 30 / 2026, page. 40 / 366 / 344 “cancer” can be any cancer, including any of the following: acute lymphocytic carcinoma, acute myeloid leukemia, alveolar rhabdomyosarcoma, bone cancer, brain cancer, breast cancer, cancer of the anus, anal canal, or anorectal region, eye cancer, intrahepatic bile duct cancer, joint cancer, cancer of the neck, gallbladder, or pleura, cancer of the nose, nasal cavity, or middle ear, vulvar cancer, chronic lymphocytic leukemia, chronic myeloid carcinoma, cervical cancer, glioma, Hodgkin's lymphoma, hypopharyngeal cancer, kidney cancer, laryngeal cancer, liver cancer, lung cancer, malignant mesothelioma, melanoma, multiple myeloma, nasopharyngeal cancer, non-Hodgkin's lymphoma, ovarian cancer, peritoneal, omental, and mesenteric cancer, pharyngeal cancer, prostate cancer, rectal cancer, kidney cancer, cancer of Skin cancer, soft tissue cancer, testicular cancer, thyroid cancer, ureter cancer, bladder cancerand cancer of the digestive tract such as, for example, esophageal cancer, gastric cancer, pancreatic cancer, stomach cancer, small intestine cancer, gastrointestinal carcinoid tumor, oral cavity cancer, colon cancer, and hepatobiliary cancer. In some forms, the cancer is melanoma. In some forms, the cancer is metastatic melanoma.

[00112] As used herein, the term “mammal” refers to any mammal, including, but not limited to, mammals of the order Rodentia, such as mice and hamsters, and mammals of the order Logomorpha, such as rabbits. In some embodiments, mammals are of the order Carnivora, including felines (cats) and canines (dogs). In some embodiments, mammals are of the order Artiodactyla, including bovines (cows) and swine (pigs), or of the order Persodactyla, including equines (horses). It is more preferred that mammals be of the order Primates, Ceboids, or Simoids (monkeys) or of the order Anthropoids (humans and howler monkeys). In some embodiments, the mammal is the human being.

[00113] The term “regression”, as well as the words that originate Petition 870260029606, dated 30 / 03 / 2026, p. 41 / 366 / 344. The term "regression," as used herein, does not necessarily imply 100% or complete regression. Instead, there are varying degrees of regression that a person of ordinary professional knowledge in the art would recognize as having a potential therapeutic benefit or effect. In this respect, the inventive methods may provide any amount of any level of cancer regression in a mammal. Furthermore, the regression provided by the inventive method may include the regression of one or more disease conditions or symptoms, for example, cancer. Also, for the purposes herein, "regression" may encompass delaying the onset of the disease, or delaying the onset of a symptom and / or delaying the onset of a condition thereof.

[00114] An “effective amount” or “therapeutically effective amount” of a composition includes that amount of the composition which is sufficient to provide a beneficial effect to the subject to whom the composition is administered. An “effective amount” of a delivery vehicle includes that amount which is sufficient to effectively bind or release a composition.

[00115] “Coding” includes the inherent property of specific nucleotide sequences in a polynucleotide, such as a gene, cDNA, or mRNA, to serve as templates for the synthesis of other polymers and macromolecules in biological processes having a defined nucleotide sequence (i.e., rRNA, tRNA, and mRNA) or a defined amino acid sequence and the resulting biological properties thereof. Thus, a gene codes for a protein if, for example, the transcription and translation of mRNA corresponding to this gene produces the protein in a cell or other biological system. Both the coding strand, the nucleotide sequence of which is identical to the mRNA sequence and is usually provided in sequence listings, and the non-coding strand, used as the template for the transcription of a gene or cDNA, can be referred to as encoding the protein or other product of this gene or cDNA. Petition 870260029606, dated 03 / 30 / 2026, p. 42 / 366 / 344

[00116] As used herein, “endogenous” includes any material from or produced within an organism, cell, tissue, or system.

[00117] As used herein, the term “exogenous” includes any material introduced from or produced outside an organism, cell, tissue, or system.

[00118] An “expression cassette” includes any nucleic acid construct capable of directing the expression of a gene / coding sequence of interest, which is operably linked to an expression cassette promoter. Such cassettes may be constructed into a “vector”, “vector construct”, “expression vector”, or “gene transfer vector”, in order to transfer the expression cassette into target cells. Thus, the term includes cloning and expression vehicles, as well as viral vectors.

[00119] As used herein, the term “fragment,” as applied to a nucleic acid or polypeptide, includes a subsequence of a larger nucleic acid or polypeptide. A “fragment” of a nucleic acid may have at least about 15 nucleotides in length; for example, at least about 50 nucleotides to about 100 nucleotides; at least about 100 to about 500 nucleotides; at least about 500 to about 1000 nucleotides; at least about 1000 to about 1500 nucleotides; or about 1500 to about 2500 nucleotides; or about 2500 nucleotides (and any integer value between these).A “fragment” of a polypeptide can be at least about 15 amino acids long; for example, at least about 50 amino acids to about 100 amino acids; at least about 100 to about 500 amino acids; at least about 500 to about 1000 amino acids; at least about 1000 to about 1500 amino acids; or about 1500 to about 2500 amino acids; or about 2500 amino acids (and any integer value in between).

[00120] As used herein, the terms “gene” and “recombinant gene” Petition 870260029606, dated 30 / 03 / 2026, pp. 43 / 366 / 344, includes nucleic acid molecules comprising an open reading frame encoding a polypeptide. Such natural allelic variations can typically result in 1 to 5% variation in the nucleotide sequence of a given gene. Alternative alleles can be identified by sequencing the gene of interest in several different individuals. This can be easily accomplished using hybridization probes to identify the same genetic locus in a variety of individuals. Any and all such nucleotide variations and resulting polymorphisms or amino acid variations that are the result of natural allelic variation and that do not alter functional activity are intended to be within the scope of the invention.

[00121] “Homologous” as used herein, includes the similarity of subunit sequence between two polymeric molecules, for example between two nucleic acid molecules, for example, two DNA molecules or two RNA molecules, or between two polypeptide molecules. When a subunit position in both of the two molecules is occupied by the same monomeric subunit, for example, if a position in each of the two DNA molecules is occupied by adenine, then they are homologous at this position. The homology between two sequences is a direct function of the number of matching or homologous positions, for example if half (for example, five positions in a ten-subunit polymer in length) of the positions in two compound sequences are homologous then the two sequences are 50% homologous, if 90% of the positions, for example 9 out of 10, are matching or homologous, the two sequences share 90% homology.As an example, the DNA sequences 5'-ATTGCC-3' and 5'-TATGGC-3' share 50% homology.

[00122] The term “inducible” includes a state in which a gene product is produced in a living cell in response to the presence of a signal in the cell. Petition 870260029606, dated 03 / 30 / 2026, p. 44 / 366 / 344

[00123] As used herein, “instructional material” includes a publication, a recording, a diagram, or any other means of expression that can be used to communicate the usefulness and / or use of a compound, composition, vector, or delivery system of the present disclosure in a kit according to the present disclosure, for example, a kit to effect the relief of the various diseases or disorders mentioned herein. Optionally, or alternatively, the instructional material may describe one or more methods for relieving the diseases or disorders in a cell or tissue of a mammal. The instructional material of the kit of the invention, for example, may be attached to a container containing the identified compound, composition, vector, or delivery system of the invention or be sent together with a container containing the identified compound, composition, vector, or delivery system.Alternatively, the instructional material may be sent separately from the container with the intention that the instructional material and the compound be used cooperatively by the recipient.

[00124] The term “nucleic acid” includes RNA or DNA molecules having more than one nucleotide in any form, including single-stranded, double-stranded, oligonucleotide, or polynucleotide. The term “nucleotide sequence” includes the arrangement of nucleotides in an oligonucleotide or polynucleotide in a single-stranded form of nucleic acid.

[00125] By “nucleic acid construct” is meant a nucleic acid sequence that has been constructed to comprise one or more functional units not found together in nature. Examples include circular, linear, double-stranded, extrachromosomal (plasmids), cosmid (plasmids containing lambda phage COS sequences), viral genomes including non-native nucleic acid sequences, and the like.

[00126] The term “operably connected” as used herein includes a Petition 870260029606, dated 03 / 30 / 2026, page 45 / 366 / 344 A polynucleotide in functional relation to a second polynucleotide, for example, a single-stranded or double-stranded nucleic acid portion comprising the two polynucleotides arranged within the nucleic acid portion in such a way that at least one of the two polynucleotides is capable of exerting a physiological effect by which it is distinguished, upon the other. By way of example, a promoter operably linked to the coding region of a gene is capable of promoting transcription of the coding region. The order specified when indicating operably linked is not important. For example, the phrases: “the promoter is operably linked to the nucleotide sequence” and “the nucleotide sequence is operably linked to the promoter” are used interchangeably here and are considered equivalent.In some cases, when the nucleic acid encoding the desired protein also comprises a promoter / regulatory sequence, the promoter / regulatory sequence is positioned at the 5' end of the desired protein coding sequence such that it directs the expression of the desired protein in a cell.

[00127] The terms “oligonucleotide”, “polynucleotide”, and “nucleic acid molecule”, used here interchangeably, refer to one of the polymeric forms of nucleotides of any length, ribonucleotides or deoxyribonucleotides. Thus, this term includes, but is not limited to, single-stranded, double-stranded, or multi-stranded DNA or RNA, genomic DNA, cDNA, DNA-RNA hybrids, or a polymer comprising purine and pyrimidine bases or other natural, chemically or biochemically modified, non-natural bases, or derivatized nucleotide bases.The polynucleotide backbone may comprise sugars and phosphate groups (as is typically found in RNA or DNA), or modified or substituted sugar or phosphate groups. Alternatively, the polynucleotide backbone may comprise a polymer of synthetic subunits such as phosphoramidites, and / or... Petition 870260029606, dated 03 / 30 / 2026, page 46 / 366 / 344 phosphorothioates, and thus may be a phosphoramidate oligodeoxynucleoside or a mixed phosphoramidate-phosphodiester oligomer. Peyrottes et al. (1996) Nucl. Acids Res. 24: 1841-1848; Chaturvedi et al. (1996) Nucl. Acids Res. 24: 2318-2323. The polynucleotide may comprise one or more L-nucleosides. A polynucleotide may comprise modified nucleotides, such as methylated nucleotides and nucleotide analogs, and may be interrupted by non-nucleotide components. If present, modifications to the nucleotide structure may be introduced before or after polymer assembly. A polynucleotide may comprise modified nucleotides, such as methylated nucleotides and nucleotide analogs, uracil, other sugars, and linking groups such as fluororibose and thioate, and nucleotide branches. The nucleotide sequence may be interrupted by non-nucleotide components.A polynucleotide can be further modified after polymerization, such as by conjugation with a labeling component. Other types of modifications included in this definition are caps, substitution of one or more of the naturally occurring nucleotides with an analog, and the introduction of a means to couple the polynucleotides to proteins, metal ions, labeling components, other polynucleotides, or a solid support. Whenever a polynucleotide or oligonucleotide is represented by a sequence of letters (uppercase or lowercase), such as “ATGCCTG”, it will be understood that the nucleotides are in the order of 5'03' from left to right and that “A” indicates deoxyadenosine, “C” indicates deoxycytidine, “G” indicates deoxyguanosine, and “T” indicates thymidine, “I” indicates deoxyinosine, “U” indicates uridine, unless otherwise indicated or obvious from the context.Unless otherwise stated, the terminology and atom numbering conventions will follow those published in Strachan and Read, Human Molecular Genetics 2 (Wiley-Liss, New York, 1999). Polynucleotides can be single, double, or... Petition 870260029606, dated 30 / 03 / 2026, p. 47 / 366 / 344 triplex, linear or circular, and can be of any length. In the polynucleotide debate, a sequence or structure of a particular polynucleotide can be described here according to the convention of providing the sequence in the 5' to 3' direction.

[00128] The term “recombinant”, as applied to a polynucleotide, means that the polynucleotide is the product of various combinations of cloning, restriction or ligation steps, and other procedures resulting in a construct distinct from and / or different from a polynucleotide found in nature. The terms respectively include replicas of the original polynucleotide construct and progeny of the original viral construct.

[00129] The term “Programmed Death Ligand 1 (PD-L1) binding protein” refers to a polypeptide (e.g., a fusion protein, an scFV, a maxibody, an antibody, and the like) that is capable of specifically binding to Programmed Death Ligand 1 (PD-L1) protein (aka CD274 or B7-H1) expressed on the surface of a cell.

[00130] The terms “polypeptide”, “peptide”, and “protein”, used herein interchangeably, refer to a polymeric form of amino acids of any length, which may include coded and non-coded amino acids, chemically or biochemically modified or derivatized amino acids, and polypeptides having modified peptide back chains. The term includes polypeptide chains modified or derivatized in any manner, including, but not limited to, glycosylation, formylation, cyclization, acetylation, phosphorylation, and the like. The term includes naturally occurring peptides, synthetic peptides, and peptides comprising one or more amino acid analogs. The term includes fusion proteins, including, but not limited to, fusion proteins with a heterologous amino acid sequence, fusions with heterologous and homologous leader sequences, with or without N-terminal methionine residues; immunologically labeled proteins; and the like. Petition 870260029606, dated 03 / 30 / 2026, page 48 / 366 / 344

[00131] The term “tumor-associated antigen” is a well-understood term in the art, and refers to molecules that are differentially overexpressed in tumor cells compared to non-cancerous cells of the same cell type. As used herein, “tumor-associated antigen” includes not only complete tumor-associated antigens that may be expressed on the cell surface, but also epitope-comprising portions (fragments) thereof that are recognized by T cells. A tumor-associated antigen (TAA) may be one found in nature, or it may be a synthetic version of a naturally occurring TAA, or it may be a variant of a naturally occurring TAA, for example, a variant that has enhanced immunogenic properties. The TAA may be a naturally occurring overexpressed protein or a mutated protein expressed only in tumor cells or other cells transformed into tumors.

[00132] The term “promoter” as used herein includes a DNA sequence operably linked to a nucleic acid sequence to be transcribed, such as a nucleic acid sequence encoding a desired molecule. A promoter is generally positioned upstream of a nucleic acid sequence to be transcribed and provides a site for specific binding by RNA polymerase and other transcription factors.

[00133] The terms “polypeptide,” “peptide,” and “protein” are used interchangeably herein to refer to polymers of amino acids of any length. The “polypeptides,” “proteins,” and “peptides” encoded by the “polynucleotide sequence” include native, full-size sequences, as with naturally occurring proteins, as well as functional subsequences, modified forms, or sequence variants, provided that the subsequence, modified form, or variant retains some degree of functionality of the native, full-size protein. In the methods and uses described herein, such polypeptides, proteins, and peptides encoded by the polynucleotide sequence may be, but not Petition 870260029606, dated 30 / 03 / 2026, pp. 49 / 366 / 344, requires that the products be identical to the defective endogenous protein, or one whose expression is insufficient or deficient in the treated mammal. The terms also encompass a modified amino acid polymer; for example, disulfide bond formation, glycosylation, lipidation, phosphorylation, methylation, carboxylation, deamidation, acetylation, or conjugation with a labeling component. Polypeptides such as anti-angiogenic polypeptides, neuroprotective polypeptides, and the like, when discussed in the context of delivering a gene product to a mammalian subject, and compositions for such, refer to the respective intact polypeptide, or any genetically engineered fragment or derivative thereof, retaining the desired biochemical function of the intact protein.

[00134] A “recombinant polypeptide” includes one that is produced upon the expression of a recombinant polynucleotide.

[00135] The term “specifically binds,” as used herein, for example, with respect to an antibody / antigen-binding region, includes an antibody / antigen-binding region that recognizes a specific antigen but does not substantially recognize or bind other molecules in a sample. For example, an antibody (e.g., an scFV) that specifically binds to an antigen of one species may also bind to this antigen of one or more other species. However, such cross-species reactivity alone does not alter the classification of an antibody as specific. As another example, an antibody that specifically binds to an antigen may also bind to different allelic forms of the antigen. However, such cross-reactivity alone does not alter the classification of an antibody as specific.

[00136] In some cases, the terms “specific binding” or “specifically ligand” may be used in reference to the interaction of an antibody, a protein, or a peptide with a second chemical species, meaning that the interaction is dependent on the presence of a structure. Petition 870260029606, dated 30 / 03 / 2026, p. 50 / 366 / 344 particular (for example, an antigenic determinant or epitope) in chemical species; for example, an antibody recognizes and binds to a specific protein structure rather than to proteins in general. If an antibody is specific for epitope “A”, the presence of a molecule containing epitope A (or free, unlabeled A), in a reaction containing labeled “A” and the antibody, will reduce the amount of labeled A bound to the antibody.

[00137] The term “synthetic antibody” as used herein includes an antibody that is generated using recombinant DNA technology, such as, for example, an antibody expressed by a bacteriophage. The term should also be interpreted to mean an antibody that has been generated by the synthesis of a DNA molecule encoding the antibody and that the DNA molecule expresses an antibody protein, or an amino acid sequence specifying the antibody, wherein the DNA or amino acid sequence has been obtained using synthetic DNA or amino acid sequencing technology that is available and well-known in the art.

[00138] “Variant,” as the term is used herein, includes a nucleic acid sequence or a peptide sequence that differs in sequence from a reference nucleic acid sequence or peptide sequence, respectively, but retains the essential biological properties of the reference molecule. Changes in the sequence of a nucleic acid variant may not alter the amino acid sequence of a peptide encoded by the reference nucleic acid, or may result in amino acid substitutions, additions, deletions, fusions, and truncations. Changes in the sequence of peptide variants are typically limited or conservative, so that the sequences of the reference and variant peptides are closely similar overall and, in many regions, identical. A variant and reference peptide may differ in amino acid sequence by one or more substitutions, additions, deletions, or in any combination.A variant of a nucleic acid or peptide can be a naturally occurring one such as... Petition 870260029606, dated 03 / 30 / 2026, page 51 / 366 / 344 an allelic variant, or it may be a variant that is not known to occur naturally. Non-naturally occurring variants of nucleic acids and peptides can be manufactured by mutagenesis techniques or by direct synthesis.

[00139] A “substitution” results from the exchange of one or more amino acids or nucleotides for different amino acids or nucleotides, respectively, when compared to an amino acid or nucleotide sequence of a polypeptide. If a substitution is conservative, the amino acid that is substituted in a polypeptide has similar structural or chemical properties (e.g., charge, polarity, hydrophobicity, and the like) to the amino acid that is replacing it.Naturally occurring conservative amino acid substitutions (“conservative amino acid substitutions”) usually result in the substitution of a first amino acid with a second amino acid from the same group as the first amino acid, where examples of amino acid groups are as follows: (1) acidic (negatively charged) amino acids such as aspartic acid and glutamic acid; (2) basic (positively charged) amino acids such as arginine, histidine, and lysine; (3) neutral polar amino acids such as glycine, serine, threonine, cysteine, tyrosine, asparagine, and glutamine; and (4) neutral nonpolar amino acids such as alanine, leucine, isoleucine, valine, proline, phenylalanine, tryptophan, and methionine. In some embodiments, polypeptide variants may have “non-conservative” changes, where the substituted amino acid differs in structural and / or chemical properties.

[00140] A “deletion” is defined as a change in the amino acid or nucleotide sequence in which one or more amino acids or nucleotide residues, respectively, are absent when compared to a naturally occurring amino acid or nucleotide sequence of a polypeptide or polynucleotide. In the context of a sequence of Petition 870260029606, dated 03 / 30 / 2026, page 52 / 366 / 344 polypeptide or polynucleotide, a deletion may involve the deletion of 2, 5, 10, up to 20, up to 30, or up to 50 or more amino acids or nucleotide residues, taking into account the extent of the polypeptide or polynucleotide sequence that is modified.

[00141] An “insertion” or “addition” is that change in an amino acid or nucleotide sequence that resulted in the addition of one or more amino acid or nucleotide residues, respectively, when compared to a naturally occurring amino acid or nucleotide sequence of a polypeptide or polynucleotide. “Insertion” generally refers to the addition of one or more amino acid residues within an amino acid sequence of a polypeptide (or nucleotide residues within a polynucleotide), while “addition” can be an insertion or refer to amino acid residues added to the N- or C-terminus of a polypeptide (or nucleotide residues added to the 5' or 3' ends of a polynucleotide). In the context of a polypeptide or polynucleotide sequence, an insertion or addition can be up to 10, up to 20, up to 30, or up to 50 or more amino acids (or nucleotide residues).

[00142] An “isolated” plasmid, nucleic acid, vector, or other substance refers to a preparation of the substance deprived of at least some of the other components present where the substance or a similar substance occurs naturally or from which it is initially prepared. Thus, for example, a substance may be prepared using a purification technique to enrich it from a source mixture. The enrichment may be measured on an absolute basis, such as weight per volume of solution, or it may be measured relative to a second, potentially interfering substance present in the source mixture. Increasing enrichments of the embodiments of this invention are increasingly more isolated. A plasmid, nucleic acid, vector, or other Petition 870260029606, dated 30 / 03 / 2026, p. 53 / 366 / 344 isolated substances are in some embodiments purified, for example, from about 80% to about 90% pure, at least about 90% pure, at least about 95% pure, at least about 98% pure, or at least about 99%, or more, pure.

[00143] A “vector” is capable of transferring gene sequences to target cells. Typically, “vector construct,” “expression vector,” and “gene transfer vector” mean any nucleic acid construct capable of directing the expression of a gene of interest and that can transfer gene sequences to target cells, which can be accomplished by genomic integration of all or a portion of the vector, or transient or heritable maintenance of the vector as an extrachromosomal element. Thus, the term includes cloning, and expression vehicles, as well as integration vectors.

[00144] The term “regulatory element” as used herein includes a nucleotide sequence that controls some aspect of the expression of nucleic acid sequences. Examples of regulatory elements illustratively include an enhancer, an internal ribosome entry site (IRES), an intron, an origin of replication, a polyadenylation signal (pA), a promoter, an enhancer, a transcription termination sequence, and an upstream regulatory domain, which contributes to the replication, transcription, and / or post-transcriptional processing of a nucleic acid sequence. In some cases, regulatory elements may also include cis-regulatory DNA elements as well as reversible elements (TEs). Those with common professional knowledge in the art are able to select and use these and other regulatory elements in an expression construct with no more than routine experimentation.Expression constructs can be generated using a recombinant genetic method or synthetically using well-known methodology.

[00145] A “control element” or “control sequence” is a Petition 870260029606, dated 03 / 30 / 2026, page 54 / 366 / 344 nucleotide sequence involved in an interaction of molecules contributing to the functional regulation of a polynucleotide, including replication, duplication, transcription, joining, translation, or degradation of the polynucleotide. Regulation can affect the frequency, rate, or specificity of the process, and can be enhancing or inhibitory in nature. Known control elements in the art include, for example, transcriptional regulatory sequences such as promoters and enhancers. A promoter is a region of DNA capable, under certain conditions, of binding RNA polymerase and initiating transcription of a coding region usually located downstream (in the 3' direction) of the promoter.

[00146] “Operatively linked” or “operably bound” refers to a juxtaposition of genetic elements, in which the elements are in a relationship that allows them to operate in the expected manner. For example, a promoter is operatively linked to a coding region if the promoter helps to initiate transcription of the coding sequence. There may be intervening residues between the promoter and the coding region as long as this functional relationship is maintained.

[00147] The terms “cancer,” “neoplasm,” “tumor,” and “carcinoma” are used here interchangeably to refer to cells that exhibit relatively autonomous growth, such that they display an aberrant growth phenotype distinguished by a significant loss of control of cell proliferation. Cancerous cells can be benign or malignant. Examples of various cancers include, but are not limited to, breast cancer, prostate cancer, ovarian cancer, cervical cancer, skin cancer, pancreatic cancer, colorectal cancer, kidney cancer, liver cancer, brain cancer, lymphoma, leukemia, lung cancer, and the like.

[00148] The phrase “tumor homologue” is intended for any tumor composed of tissue of the same type from which it develops. Additionally, a tumor may be homologous to TILs derived from said tumor. Petition 870260029606, dated 30 / 03 / 2026, page 55 / 366 / 344 tumor. For example, a melanoma tumor may be homologous to TILs derived from the melanoma tumor and / or TILs derived from a melanoma tumor may be used to treat the homologous melanoma tumor from which they were derived. In some embodiments, TILs derived from the homologous tumor may be used to treat the homologous tumor.

[00149] By “individual” or “host” or “subject” or “patient” is meant any mammalian subject for whom diagnosis, treatment, or therapy is desired, particularly human beings. Other subjects may include cattle, dogs, cats, guinea pigs, rabbits, rats, mice, horses, and so forth.

[00150] As used herein, the term “isolate,” when used in the context of an isolated compound, refers to a compound of interest that is in an environment different from that in which the compound naturally occurs. “Isolate” is intended to include compounds that are within samples that are substantially enriched with the compound of interest and / or in which the compound of interest is partially or substantially purified.

[00151] As used herein, the term “substantially pure” refers to a compound that is removed from its natural environment and is at least 60% free, 75% free, or 90% free of other components with which it is naturally associated.

[00152] Techniques for determining nucleic acid and amino acid “sequence identity” are known in the art. Typically, such techniques include determining the mRNA nucleotide sequence for a gene and / or determining the amino acid sequence encoded by it, and comparing these sequences with a second nucleotide or amino acid sequence. In general, “identity” refers to an exact nucleotide-to-nucleotide or amino acid-to-amino acid match of two polynucleotide or polypeptide sequences, respectively. Two or more sequences Petition 870260029606, dated 03 / 30 / 2026, p. 56 / 366 / 344 (polynucleotide or amino acid) can be compared by determining their “percent identity”. The percent identity of two sequences, whether nucleic acid or amino acid sequences, is the number of exact matches between two aligned sequences divided by the length of the shorter sequence and multiplied by 100. An approximate alignment for nucleic acid sequences is provided by the local homology algorithm of Smith and Waterman, Advances in Applied Mathematics, 2: 482-489 (1981). This algorithm can be applied to amino acid sequences using the counting matrix developed by Dayhoff, Atlas of Protein Sequences and Structure, MO Dayhoff ed., 5 suppl. 3: 353-358, National Biomedical Research Foundation, Lavarton, DC, USA, and standardized by Gribskov, Nucl. Acids Res. 14(6): 6745-6763 (1986).

[00153] An example of an implementation of this algorithm for determining the percent identity of a sequence is provided by the Genetics Computer Group (Madison, WI) in the utility application “BestFit”. The default parameters for this method are described in the Wisconsin Sequence Analysis Package Program Manual, Version 8 (1995) (available from Genetics Computer Group, Madison, WI). Another method for establishing percent identity in the context of the present invention is to use the MPSRCH package of copyrighted programs acquired by the University of Edinburgh, developed by John F. Collins and Shane S. Sturrok, and distributed by IntelliGenetics, Inc. (Mountain View, CA). From this package set, the Smith-Waterman algorithm can be used where default parameters are used for the counting table (e.g., interval opening penalty of 12, interval extension penalty of one, and an interval of six).From the generated data, the “Match” value reflects the “sequence identity”. Other suitable programs for calculating the percentage identity or similarity between sequences are generally known in the art; for example, another alignment program is BLAST, which is used. Petition 870260029606, dated 30 / 03 / 2026, page 57 / 366 / 344 with default parameters. For example, BLASTN and BLASTP can be used using the following default parameters: genetic code = default; filter = none; strand = both; cut = 60; expectation = 10; Matrix = BLOSUM62; Descriptions = 50 sequences; sorted by = HIGH SCORE; Databases = non-redundant, GenBank + EMBL + DDBJ + PDB + GenBank CDS translations + Swiss protein + Spupdate + PIR. Details of these programs can be found at the internet address located by placing http: / / in front of blast.ncbi.nlm.nih.gov / Blast.cgi.

[00154] Alternatively, in the context of polynucleotides, homology can be determined by hybridizing polynucleotides under conditions that form stable duplexes between homologous regions, followed by digestion with specific single-strand nuclease(s), and determining the size of the digested fragments.

[00155] Two DNA sequences, or two polypeptide sequences, are “substantially homologous” to each other when the sequences exhibit at least about 80% to 85%, at least about 85% to 90%, at least about 90% to 95%, or at least about 95% to 98% sequence identity with respect to a defined length of the molecules, as determined using the methods above. As used herein, substantially homologous also refers to sequences showing complete identity with the specified DNA or polypeptide sequence. DNA sequences that are substantially homologous can be identified in a Southern hybridization experiment under, for example, severe conditions, as defined for this particular system. Defining the appropriate hybridization conditions is within the professional knowledge of the technique. See, for example, Sambrook and Russel, Molecular Cloning: A Laboratory Manual Third Edition, (2001) Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY.

[00156] A first polynucleotide is “derived from” a second Petition 870260029606, dated 30 / 03 / 2026, p. 58 / 366 / 344 polynucleotide if it has the same or substantially the same nucleotide sequence as a region of the second polynucleotide, its cDNA, complements thereof, or if it demonstrates sequence identity as described above. This term is not intended to require or imply that the polynucleotide must be obtained from the cited source (although such is encompassed), but rather may be obtained by any suitable method.

[00157] A first polypeptide (or peptide) is “derived from” a second polypeptide (or peptide) if it is (i) encoded by a first polynucleotide derived from a second polynucleotide, or (ii) demonstrates sequence identity to the second polypeptide as described above. This term is not intended to require or imply that the polynucleotide must be obtained from the cited source (although such is encompassed), but rather may be made by any suitable method. The term “in combination with” as used herein refers to uses where, for example, a first therapy is administered during the entire course of administration of a second therapy; where the first therapy is administered during a period of time that overlaps with the administration of the second therapy, for example where the administration of the first therapy begins before the administration of the second therapy and the administration of the first therapy ends before the administration of the second therapy ends;where the administration of the second therapy begins before the administration of the first therapy and the administration of the second therapy ends before the administration of the first therapy ends; where the administration of the first therapy begins before the administration of the second therapy begins and the administration of the second therapy ends before the administration of the first therapy ends; where the administration of the second therapy begins before the administration of the first therapy begins and the administration of the first therapy ends before the administration of the second therapy ends. As such, “in combination” can also refer to the regimen; Petition 870260029606, dated 30 / 03 / 2026, p. 59 / 366 / 344 involving the administration of two or more therapies. “In combination with” as used here also refers to the administration of two or more therapies that may be administered in the same or different formulations, by the same or different routes, and in the same or different dosage forms.

[00158] The terms “treatment,” “treating,” “to treat,” and the like, refer to obtaining a desired pharmacological and / or physiological effect. The effect may be prophylactic in terms of completely or partially preventing a disease or symptom thereof and / or may be therapeutic in terms of a partial or complete cure for a disease and / or adverse effect attributable to the disease. “Treatment,” as used herein, encompasses any treatment of a disease in a mammal, particularly in a human being, and includes: (a) preventing the disease from occurring in a subject who may be predisposed to the disease but has not yet been diagnosed as having it; (b) inhibiting the disease, that is, halting its development or progression; and (c) alleviating the disease, that is, causing regression of the disease and / or alleviating one or more symptoms of the disease. “Treatment” is also intended to encompass the release of an agent so as to provide a pharmacological effect, even in the absence of a disease or condition.For example, "treatment" encompasses the release of a composition that can evoke an immune response or confer immunity in the absence of a disease condition, for example, in the case of a vaccine.

[00159] Any and all publications (including patents and patent application publications) mentioned herein are incorporated herein by reference to disclose and describe the methods and / or materials in connection with which the publications are cited.

[00160] The publications disclosed here are provided for publication prior to the filing date of this application. Furthermore, the publication dates provided may differ from the actual publication dates. Petition 870260029606, dated 30 / 03 / 2026, page 60 / 366 / 344 may need to be independently verified. To the extent that such publications may present a definition that conflicts with an explicit or implicit definition or disclosure of this disclosure, the definition or disclosure of this disclosure controls.

[00161] As will become evident to those with professional knowledge in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has separate components and features that can be easily separated from or combined with the features of any of the other diverse embodiments without departing from the scope or spirit of the present invention. Any method cited can be carried out in the order of events cited or in any other order that is logically possible. Compositions Proteins (e.g., antibodies) that specifically bind to PD-L1

[00162] Proteins are provided (e.g., antibodies) that specifically bind to PD-L1, nucleic acids that encode the proteins, and cells that include a protein in question and / or a nucleic acid that encodes a protein in question. Throughout this disclosure, a “protein that specifically binds to PD-L1” that includes an antigen-binding region as described here is also referred to as a “PD-L1-binding protein”.

[00163] Two novel recombinant antibodies are provided (hereinafter referred to as “38A1” and “19H9”), both of which specifically bind to human Programmed Death Ligand 1 (PD-L1). Human PD-L1, NCBI Accession NP_054862 (Version NP_054862.1 GI: 7661534), is a 290 aa protein having the amino acid sequence (which includes a putative signal peptide at aa 1-18 and an ectodomain at amino acids 19-238): MRIFAVFIFMTYWHLLNAFTVTVPKDLYVVEYGSNMTIECKFPVEKQ LDLAALIVYWEMEDKNIIQFVHGEEDLKVQHSSYRQRARLLKDQLSL Petition 870260029606, dated 03 / 30 / 2026, page 61 / 366 / 344 GNAALQITDVKLQDAGVYRCMISYGGADYKRITVKVNAPYNKINQRI LVVDPVTSEHELTCQAEGYPKAEVIWTSSDHQVLSGKTTTTNSKREE KLFNVTSTLRINTTTNEIFYCTFRRLDPEENHTAELVIPELPLAHPPNER THLVILGAILLCLGVALTFIFRLRKGRMMDVKKCGIQDTNSKKQSDTH LEET (SEQ ID NO: 21) PD-L1 is also known as CD274 and B7-H1, and is expressed on the surface of a cell, for example, a tumor cell.

[00164] Sequence details, including CDR sequences, and additional information related to antibodies 38A1 and 19H9 are presented in Figure 7. As such, in some cases, a protein in question that specifically binds to PD-L1 has an antigen-binding portion that includes a first polypeptide that includes the 3 CDR amino acid sequences presented in SEQ ID NOs: 2-4 (light chain CDRs L1, L2, and L3, respectively, of scFV 38A1), and a second polypeptide that includes the 3 CDR amino acid sequences presented in SEQ ID NOs: 68 (heavy chain CDRs H1, H2, and H3, respectively, of scFV 38A1).In some cases, a protein in question that specifically binds to PD-L1 has an antigen-binding portion that includes a first polypeptide containing the 3 CDR amino acid sequences presented in SEQ ID numbers: 2-4 (light chain CDRs L1, L2, and L3, respectively, of scFV 38A1), and a second polypeptide containing the 3 CDR amino acid sequences presented in SEQ ID numbers: 6-8 (heavy chain CDRs H1, H2, and H3, respectively, of scFV 38A1), with the exception that the first and / or second polypeptide may include one or more conservative amino acid substitutions with respect to the specified SEQ ID number, provided that the protein specifically binds to PD-L1. In some cases, the first and / or second polypeptide may include two or fewer (e.g., one or fewer) conservative amino acid substitutions within each amino acid stretch that corresponds to the specified SEQ ID numbers, provided that... Petition 870260029606, dated 30 / 03 / 2026, p. 62 / 366 / 344, states that the protein specifically binds to PD-L1. For example, such a protein in question may in some cases include two or fewer (e.g., one or fewer) conservative amino acid substitutions within each CDR.

[00165] In some cases, the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1 (light chain 38A1), and the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 5 (heavy chain 38A1) (for example, see Figure 7). In some cases, the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1, and the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 5, with the exception that the first and / or second polypeptides may include one or more conservative amino acid substitutions with respect to the specified SEQ ID numbers, provided that the protein specifically binds to PD-L1.In some cases, the first and / or second polypeptides may include two or fewer (e.g., one or fewer) conservative amino acid substitutions within each amino acid stretch corresponding to the specified SEQ ID numbers, provided that the protein specifically binds to PD-L1. For example, such a protein may in some cases include two or fewer (e.g., one or fewer) conservative amino acid substitutions within each CDR. In some embodiments, the first polypeptide comprises the CDRs cited in SEQ ID numbers 2, 3, and 4, wherein the protein specifically binds to PD-L1. In some embodiments, the second polypeptide comprises the CDRs cited in SEQ ID numbers 6, 7, and 8, wherein the protein specifically binds to PD-L1. In some embodiments, the PD-L1-binding protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9.In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits binding capacity. Petition 870260029606, dated 03 / 30 / 2026, p. 63 / 366 / 344 greater or increased in melanoma when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, the biological function includes blocking the interaction of PD-1 and PD-L1. In some embodiments, the biological function includes inhibition of the PD-1 and PD-L1 signaling pathway. Light chain - 38A1 antibody SYVLTQPPSVSVAPGQTARITCGGNIGRKIVHWYQQRPGQAPVLVIY YDTDRPAGIPERFSGSNSGNMATLTISTVGAGDEADYYCQVWDTGSD HVVFGGGTKLTVL (SEQ ID NO: 1) CDR1(CDR-L1): NIGRKI (SEQ ID NO: 2) CDR2(CDR-L2): YDT (SEQ ID NO: 3) CDR3(CDR-L3): QVWDTGSDHVV (SEQ ID NO: 4) Heavy chain - 38A1 antibody EVQLVESGGGLVQPGGSLRLSCAASGFTFSNYAMSWVRQAPGKGLE WVSTISGSGGTTYYADSVKGRFTISRDNSKNTLYLQMNSLRVEDTAV YYCAKDWFRSSSPDAFDIWGQGTTVTVSA (SEQ ID NO: 5) CDR1(CDR-H1): GFTFSNYA (SEQ ID NO: 6) CDR2(CDR-H2): ISGSGGTT (SEQ ID NO: 7) CDR3(CDR-H3): AKDWFRSSSPDAFDI (SEQ ID NO: 8)

[00166] In some embodiments, increased binding capacity is measured (i) by determining the percentage of PD-L1 positive cells detected in a flow cytometry assay using a protein of Petition 870260029606, dated 30 / 03 / 2026, page 64 / 366 / 344 PD-L1 binding labeled with or detectable by a fluorescent label, and (ii) comparing the number of PD-L1 positive cells obtained with the PD-L1 binding protein with a control antibody or comparing with 19H9, wherein an increase in the percentage of PD-L1 positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).

[00167] In some cases, a protein in question that specifically binds to PD-L1 has an antigen-binding portion that includes a first polypeptide that includes the 3 CDR amino acid sequences presented in SEQ ID NOs: 10-12 (light chain CDRs L1, L2, and L3, respectively of scFV 19H9), and a second polypeptide that includes the 3 CDR amino acid sequences presented in SEQ ID NOs: 14-16 (heavy chain CDRs H1, H2, and H3, respectively of scFV 19H9). In some cases, a given protein that binds specifically to PD-L1 has an antigen-binding portion that includes a first polypeptide containing the 3 CDR amino acid sequences presented in the SEQ ID NOs: 10-12 (L1, L2, and L3 light chain CDRs, respectively of scFV 19H9), and a second polypeptide containing the 3 amino acid sequences Petition 870260029606, dated 03 / 30 / 2026, p. 65 / 366 / 344 CDRs presented in SEQ ID numbers 14-16 (heavy chain CDRs H1, H2, and H3, respectively, of scFV 19H9), with the exception that the first and / or second polypeptides may include one or more conservative amino acid substitutions with respect to the specified SEQ ID numbers, provided that the protein specifically binds to PD-L1. In some cases, the first and / or second polypeptides may include two or fewer (e.g., one or fewer) conservative amino acid substitutions within each amino acid stretch corresponding to the specified SEQ ID numbers, provided that the protein specifically binds to PD-L1. For example, such a protein may in some cases include two or fewer (e.g., one or fewer) conservative amino acid substitutions within each CDR. In some embodiments, the first polypeptide comprises the CDRs cited in SEQ ID numbers 10, 11, and 12, and in which the protein specifically binds to PD-L1.In some embodiments, the second polypeptide comprises the CDRs cited in SEQ ID NOS: 14, 15, and 16, and the protein specifically binds to PD-L1. In some embodiments, the PD-L1-binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. Light chain - 19H9 antibody NFMLTQPHSVSESLGKTVTISCTGSSGSIARKFVQWYQQRPGSSPTTVI YENNQRPSGVSDRFSGSIGSSSNSASLTISGLKTEDEADYYCQSYDSSN VVFGGGTKVTVL (SEQ ID NO: 9) CDR1(CDR-L1): SGSIARKF (SEQ ID NO: 10) CDR2(CDR-L2): ENN (SEQ ID NO: 11) CDR3(CDR-L3): QSYDSSNVV (SEQ ID NO: 12) Petition 870260029606, dated 03 / 30 / 2026, p. 66 / 366 / 344 Heavy chain - 19H9 antibody QVQLQESGGGLVKPGGSLRLSCAASGFTFSSYSMNWVRQAPGKGLE WVSGINTAGDTHYPESVKGRFTISRDNARNSLNLQMNSLRAEDTAVY YCVRERVEREYSGYDAFDIWGQGTTVTVSA (SEQ ID NO: 13) CDR1(CDR-H1): GFTFSSYS (SEQ ID NO: 14) CDR2(CDR-H2): INTAGDT (SEQ ID NO: 15) CDR3(CDR-H3): VRERVEREYSGYDAFDI (SEQ ID NO: 16)

[00168] In some embodiments, the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 9 (19H9 light chain), and the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 13 (19H9 heavy chain) (e.g., see Figure 7). In some embodiments, the first polypeptide comprises the amino acid sequence 90%, 95%, or 98% identical to the amino acid sequence shown in SEQ ID NO: 9 (19H9 light chain), and the second polypeptide comprises the amino acid sequence 90%, 95%, or 98% identical to the amino acid sequence shown in SEQ ID NO: 13 (19H9 heavy chain).In some cases, the first polypeptide comprises the amino acid sequence presented in SEQ ID NO: 9, and the second polypeptide comprises the amino acid sequence presented in SEQ ID NO: 13, with the exception that the first and / or second polypeptides may include one or more conservative amino acid substitutions with respect to the specified SEQ ID numbers, provided that the protein specifically binds to PD-L1. In some cases, the first and / or second polypeptides may include two or fewer (e.g., one or fewer) conservative amino acid substitutions within each amino acid stretch corresponding to the specified SEQ ID numbers, provided that the protein specifically binds to PD-L1. For example, such a protein in question may in some cases include two or fewer (e.g., one). Petition 870260029606, dated 30 / 03 / 2026, p. 67 / 366 / 344 or less) conservative amino acid substitutions within each CDR.

[00169] In some embodiments, a question protein that specifically binds to PD-L1 is a single-chain antibody (scFv) (discussed above). As such, in some cases, a question protein that specifically binds to PD-L1 is an scFv, and the first and second polypeptides of the antigen-binding portion, as described above (e.g., in this section), are fused together (and are therefore part of the same polypeptide). Examples of suitable scFvs include, but are not limited to, those presented in SEQ ID Nos: 17 and 19 (see Figure 7). In some cases, the first and second polypeptides of an scFv are separated from each other by a ligand (e.g., a flexible ligand). Several ligands will be known to a person with common professional knowledge of the art, and any convenient ligand may be used.A flexible linker may include, for example, an amino acid sequence for a hinge region derived from an immunoglobulin heavy chain. A flexible linker may be positioned, for example, between an antigen-binding portion (an antigen-binding domain) of an antibody (e.g., an scFv) and an Fc domain of the immunoglobulin. A variety of flexible linkers are known in the art, including, for example, flexible linkers including one or more amino acids Gly, Ser, Asn, and / or Asp. In some embodiments, the flexible linker is GGGGS. In some embodiments, the flexible linker l is (GGGGS)n (SEQ ID NO: 35), where n is an integer between 1 and 10. In some embodiments, the flexible linker is GGGGS. In some embodiments, the flexible linker is GGGGSGGGGS (SEQ ID NO: 36). In some embodiments, the flexible linker is GGGGSGGGGSGGGGS (SEQ ID NO: 37). In some embodiments, the flexible binder is GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 38).In some modalities, the flexible binder is GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 39). In some modalities, the flexible binder comprises a Wing and. Petition 870260029606, dated 03 / 30 / 2026, p. 68 / 366 / 344 Pro (AP) terminal c. In some embodiments, the flexible binder is GGGSGG GGSGGGGSGAP (SEQ ID NO: 40).

[00170] The flexible scFvs ligands of SEQ ID NOs: 17 and 19 are in bold and underlined in Figure 7. In some cases, a protein in question that specifically binds to PD-L1 includes an amino acid sequence having 80% or more sequence identity (e.g., 85% or more, 90% or more, 95% or more, 98% or more, 99% or more, or 100% sequence identity) with the amino acid sequence shown in either of the SEQ ID NOs: 17 and 19 (e.g., see Figure 7).

[00171] In some modalities, scFv comprises the following sequence: EVQLVESGGGLVQPGGSLRLSCAASGFTFSNYAMSWVRQAPGKGLE WVSTISGSGGTTYYADSVKGRFTISRDNSKNTLYLQMNSLRVEDTAV YYCAKDWFRSSSPDAFDIWGQGTTVTVSAGGGGSGGGSGGGGSGA PSYVLTQPPSVSVAPGQTARITCGGNNIGRKIVHWYQQRPGQAPVLVI YYDTDRPAGIPERFSGSNSGNMATLTISTVGAGDEADYYCQVWDTGS DHVVFGGGTKLTVL (SEQ ID NO: 17).

[00172] In some modalities, the scFv comprises the following sequence: QVQLQESGGGLVKPGGSLRLSCAASGFTFSSYSMNWVRQAPGKGLE WVSGINTAGDTHYPESVKGRFTISRDNARNSLNLQMNSLRAEDTAVY YCVRERVEREYSGYDAFDIWGQGTTVTVSAGGGGSGGGGSGGGGSG APNFMLTQPHSVSESLGKTVTISCTGSSGSIARKFVQWYQQRPGSSPTT VIYENNQRPSGVSDRFSGSIGSSSNSASLTISGLKTEDEADYYCQSYDS SNVVFGGGTKVTVL (SEQ ID NO: 19).

[00173] In some forms, a protein in question that is Petition 870260029606, dated 03 / 30 / 2026, p. 69 / 366 / 344 specifically links to PD-L1 (e.g., an scFv) and is fused directly or via a ligand to an Fc domain (or a fragment thereof) (e.g., an Fc of IgG1, an Fc of IgG2, an Fc of IgG3, an Fc of IgG4, or a fragment thereof) to provide a maxibody. In some cases, Fc is an Fc domain of IgG1. In some cases, an IgG1 Fc domain has the sequence: CPPCPAPEFEGGPSVFLFPPKPKDTLMetISRTPEVTCVVVDVSQEDPEV QFNWYVDGVEVHNAKTKPREEQFQSTYRVVSVLTVLHQDWLNGKE YKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMetTKNQVSL TCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVD KSRWQEGNVFSCSVMetHEALHNHYTQKSLSLSLGK (SEQ ID NO: 22)

[00174] In some modalities, Fc is an IgG4 Fc domain. In some cases, an IgG4 FC domain has the sequence: CPPCPAPEFEGGPSVFLFPPKPKDTLMetISRTPEVTCVVVDVSQEDPEV QFNWYVDGVEVHNAKTKPREEQFQSTYRVVSVLTVLHQDWLNGKE YKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMetTKNQVSL TCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVD KSRWQEGNVFSCSVMetHEALHNHYTQKSLSLSLGK (SEQ ID NO: 23)

[00175] In some embodiments, a protein in question that binds specifically to PD-L1 is a humanized antibody. In some cases, a protein in question that binds specifically to PD-L1 is an scFv (for example, as described above) fused to an Fc domain (or a fragment thereof) (for example, an IgG1 Fc, an IgG2 Fc, an IgG3 Fc, an IgG4 Fc, or a fragment thereof).In some cases, a protein in question that specifically binds to PD-L1 includes an amino acid sequence having 80% or more sequence identity (e.g., 85% or more, 90% or more, 95% or more, 98% or more, 99% or more, or 100% sequence identity) with the amino acid sequence shown in any of the SEQ ID NOs: 18 and 20 (e.g., see a. Petition 870260029606, dated 03 / 30 / 2026, p. 70 / 366 / 344 Figure 7).

[00176] In some embodiments, the protein in question that specifically binds to PD-L1 comprises: MGSTAILALLLAVLQGVSAEVQLVESGGGLVQPGGSLRLSCAASGFT FSNYAMSWVRQAPGKGLEWVSTISGSGGTTYYADSVKGRFTISRDNS KNTLYLQMNSLRVEDTAVYYCAKDWFRSSSPDAFDIWGQGTTVTVS AGGGGSGGGGSGGGGSGAPSYVLTQPPSVSVAPGQTARITCGGNNIG RKIVHWYQQRPGQAPVLVIYYDTDRPAGIPERFSGSNSGNMATLTIST VGAGDEADYYCQVWDTGSDHVVFGGGTKLTVLGPRANFVYKSGPR PKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVD VSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQ DWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEM TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFL YSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 18).

[00177] In some embodiments, the protein in question that specifically binds to PD-L1 comprises: MGSTAILALLLAVLQGVSAQVQLQESGGGLVKPGGSLRLSCAASGFT FSSYSMNWVRQAPGKGLEWVSGINTAGDTHYPESVKGRFTISRDNAR NSLNLQMNSLRAEDTAVYYCVRERVEREYSGYDAFDIWGQGTTVTV SAGGGGSGGGGSGGGGSGAPNFMLTQPHSVSESLGKTVTISCTGSSGS IARKFVQWYQQRPGSSPTTVIYENNQRPSGVSDRFSGSSIGSSSANSASLTI SGLKTEDEADYYCQSYDSSNVVFGGGTKVTVLGPRANFVYKSGPRPK SCDKTHTCPPCPAPELLGGPSVFLFPKPKDTLMISRTPEVTCVVVDVS HEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQD WLNGKEYKCKVSNKALPAPIEKTISKAGGQPREPQVYTLPPSREEMT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLY SKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 20). Petition 870260029606, de 30 / 03 / 2026, pág. 71 / 366 / 344

[00178] A PD-L1 binding protein in question (e.g., an scFV) may be fused to a fusion partner. Examples of fusion partners for a PD-L1 binding protein in question (e.g., scFV) include but are not limited to: (A) a ligand for an NK activating receptor (e.g., ULBP1 ectodomain), (b) the Fc domain of any human immunoglobulin (e.g., IgG4 or IgG1) and its variants (e.g., monomeric hinge mutant, FcR binding mutant), (c) an autodimerizing protein (e.g., leucine zipper protein), (d) domains 3 and 4 of human CD4 (3 / 4), and (e) the Carboxy Terminal Peptide (CTP) of Human Chorionic Gonadotropin (hCG).

[00179] The example sequences of the fusion partners above are as follows, and include self-dimerizing leucine zipper proteins, human CD4 domains 3 and 4 (3 / 4), and Carboxy Terminal Peptide (CTP) of Human Chorionic Gonadotropin (hCG).

[00180] In some embodiments, the self-dimerizing leucine zipper protein comprises: RSGSSRMetKQIEDKIEEILSKIYHIENEIARIKKLIGERGTSSRG (SEQ ID NO: 24)

[00181] In some modalities, domains 3 and 4 of the human CD4 (3 / 4) comprise ASSIVYKKEGEQVEFSFPLAFTVEKLTGSGELWWQAERASSSKSWITF DLKNKEVSVKRVTQDPKLQMetGKKLPLHLTLPQALPQYAGSGNLTL ALEAKTGKLHQEVNLVVMetRATQLQKNLTCEVWGPTSPKLMetLSLK LENKEAKVSKREKAVWVLNPEAGMetWQCLLSDSGQVLLESNIKVL (SEQ ID NO: 25)

[00182] In some embodiments, the Carboxy Terminal Peptide (CTP) of Human Chorionic Gonadotropin (hCG) comprises: SSSSKAPPPSLPSPSRLPGPSDTPILPQ (SEQ ID NO: 26) PD-L1 binding protein properties & co-compositions Petition 870260029606, dated 03 / 30 / 2026, page 72 / 366 / 344

[00183] In some embodiments, the compositions and methods described include a PD-1 inhibitor that binds human PD-1 with a Kd of about 100 pM or lower, binds human PD-1 with a Kd of about 90 pM or lower, binds human PD-1 with a Kd of about 80 pM or lower, binds human PD-1 with a Kd of about 70 pM or lower, binds human PD-1 with a Kd of about 60 pM or lower, binds human PD-1 with a Kd of about 50 pM or lower, binds human PD-1 with a Kd of about 40 pM or lower, binds human PD-1 with a Kd of about 30 pM or lower, binds human PD-1 with a Kd of about 20 pM or lower, binds human PD-1 with a Kd of about 10 pM or lower, or binds human PD-1 with a KD of about 1 pM or lower.

[00184] In some embodiments, the compositions and methods described include a PD-1 inhibitor that binds to human PD-1 with a kassoc of about 7.5 x 10⁵ l / ms or faster, binds to human PD-1 with a kassoc of about 7.5 x 10⁵ l / ms or faster, binds to human PD-1 with a kassoc of about 8 x 10⁵ l / ms or faster, binds to human PD-1 with a kassoc of about 8.5 x 10⁵ l / ms or faster, binds to human PD-1 with a kassoc of about 9 x 10⁵ l / ms or faster, binds to human PD-1 with a kassoc of about 9.5 x 10⁵ l / ms or faster, or binds to human PD-1 with a kassoc of about 1 x 1061 / ms or faster.

[00185] In some embodiments, the compositions and methods described include a PD-1 inhibitor that binds to human PD-1 with a kdissoc of about 2 x 10⁻⁵¹ / s or slower, binds to human PD-1 with a kdissoc of about 2.1 x 10⁻⁵¹ / s or slower, binds to human PD-1 with a kdissoc of about 2.2 x 10⁻⁵¹ / s or slower, binds to human PD-1 with a kdissoc of about 2.3 x 10⁻⁵¹ / s or slower, binds to human PD-1 with a kdissoc of about 2.4 x 10⁻⁵¹ / s or slower, binds to human PD-1 with a kdissoc of about 2.5 x 10⁻⁵¹ / s or slower, binds to human PD-1 with a kdissoc of about 2.6 x 10-51 / s or slower or connects to PD. (Reference 870260029606, dated 30 / 03 / 2026, p.)73 / 366 / 344 human with a kdissoc of about 2.7 x 10-51 / s or slower, binds to PD-1 human with a kdissoc of about 2.8 x 10-51 / s or slower, binds to PD-1 human with a kdissoc of about 2.9 x 10-51 / s or slower, or binds to PD-1 human with a kdissoc of about 3 x 10-51 / s or slower.

[00186] In some embodiments, the compositions and methods described include a PD-1 inhibitor that blocks or inhibits the binding of human PD-L1 or human PD-L2 to human PD-1 with an IC50 of about 10 nM or lower, blocks or inhibits the binding of human PD-L1 or human PD-L2 to human PD-1 with an IC50 of about 9 nM or lower, blocks or inhibits the binding of human PD-L1 or human PD-L2 to human PD-1 with an IC50 of about 8 nM or lower, blocks or inhibits the binding of human PD-L1 or human PD-L2 to human PD-1 with an IC50 of about 7 nM or lower, blocks or inhibits the binding of human PD-L1 or human PD-L2 to human PD-1 with an IC50 of about 6 nM or lower, blocks or inhibits the binding of human PD-L1 or human PD-L2 to human PD-1 with an IC50 of about 5 nM or lower, it blocks or inhibits the binding of human PD-L1 or human PD-L2 to human PD-L1 with an IC50 of about 4 nM or lower.blocks or inhibits the binding of human PD-L1 or human PD-L2 to human PD-1 with an IC50 of about 3 nM or lower, blocks or inhibits the binding of human PD-L1 or human PD-L2 to human PD-1 with an IC50 of about 2 nM or lower, or blocks or inhibits the binding of human PD-L1 or human PD-L2 to human PD-1 with an IC50 of about 1 nM or lower.

[00187] In some embodiments, the PD-L1 binding protein is a PD-L1 antibody. In some embodiments, the PD-L1 antibody is a high-affinity antibody. In some embodiments, the PD-L1 antibody is a human PD-L1 antibody. In some embodiments, the PD-L1 antibody is a murine antibody, a chimeric antibody, or a humanized antibody. In some embodiments, the PD-L1 antibody is an antibody Petition 870260029606, dated 03 / 30 / 2026, p. 74 / 366 / 344 monoclonal. In some embodiments, the PD-L1 antibody binds to human PD-1 with a Kd of 5 x 10-8 M or less, binds to human PD-1 with a Kd of 1 x 10-8 M or less, binds to human PD-1 with a Kd of 5 x 10-9 M or less, or binds to human PD-1 with a Kd between 1 x 10-8 M and 1 x 10-10 M. In some embodiments, the PD-L1 antibody binds to human PD-1 with a Kd of 1 x 10-7 M or less. Nucleic acids that code for a given protein. Nucleic Acids and Vectors

[00188] Nucleic acids are provided that encode a specific protein (which binds specifically to PD-L1). A specific protein may be encoded by one or more nucleic acids. For example, in cases where the first and second polypeptides of the antigen-binding portion are separate polypeptides (i.e., they are not fused together), the first and second polypeptides may be encoded in the same or different nucleic acids. In some embodiments, one or more nucleic acids encoding a specific PD-L1-binding protein (e.g., antibody, scFv, a maxibody, etc.) are included in an expression vector. In some embodiments, the first and second polypeptides are encoded in the same vector. In some embodiments, the first and second polypeptides are encoded in different vectors. In some embodiments, the first polypeptide is encoded in a first vector.In some embodiments, the second polypeptide is encoded in a second vector. In some embodiments, the viral vector is a lentiviral-based vector. In some embodiments, the viral vector is pLV4301G PDLV scFV 38A1 (SEQ ID NO: 37; Figure 11A, Figure 16A). In some embodiments, the viral vector is pLV4301G PDLV scFV 19H9 (SEQ ID NO: 38; Figure 11B, Figure 16B). In some embodiments, the viral vector is a pLEV-based viral vector. In some embodiments, the viral vector is a gamma-retroviral-based vector. In some embodiments, the viral vector is a vector based on... Petition 870260029606, dated 03 / 30 / 2026, page 75 / 366 / 344 pMSCIV. In some embodiments, the viral vector encodes 19H9. In some embodiments, the viral vector is a lentiviral-based vector that encodes 19H9. In some embodiments, the viral vector is a pLEV-based viral vector that encodes 19H9. In some embodiments, the viral vector encodes 38A1. In some embodiments, the viral vector is a lentiviral-based vector that encodes 38A1. In some embodiments, the viral vector is a pLEV-based viral vector that encodes 38A1. In some embodiments, the viral vector encodes the PD-L1 binding protein. In some embodiments, the PD-L1 binding protein comprises an antigen-binding portion. In some modalities, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some modalities, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared with 19H9. In some embodiments, the increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the percentage of PD-L1-positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some modalities, the increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the protein of. Petition 870260029606, dated 03 / 30 / 2026, page 76 / 366 / 344, PD-L1 binding with a control antibody or compared to 19H9, where an increase in the MFI of the total cell population by flow cytometry with PD-L1 binding protein when compared to a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, PD-L1 binding protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, biological function includes blocking PD-1 and PD-L1 binding. In some embodiments, biological function includes inhibition of the PD-1 and PD-L1 signaling pathway. In some forms, PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1.In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the PDL1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the heavy and light chains are encoded in the same vector. In some embodiments, the heavy and light chains are encoded in different vectors. In some embodiments, the heavy chain is encoded in a first vector. In some embodiments, the light chain is encoded in a second vector.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is... Petition 870260029606, dated 30 / 03 / 2026, p. 77 / 366 / 344 an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDR-H1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3). In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. Petition 870260029606, dated 03 / 30 / 2026, p. 78 / 366 / 344 In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.

[00189] Retrovirus-derived vectors such as lentiviruses are suitable tools for achieving long-duration gene transfer. Petition 870260029606, dated 03 / 30 / 2026, pp. 79 / 366 / 344, given that they allow for long-lasting, stable integration of a transgene and its propagation in daughter cells. Lentiviral vectors have the additional advantage over vectors derived from oncoretroviruses such as murine leukemia viruses in that they can transduce non-proliferating cells, such as hepatocytes. They also have the additional advantage of low immunogenicity.

[00190] The expression vector can be provided to a cell (e.g., introduced into a cell) in the form of a viral vector. Viral vector technology is well known in the art and is described, for example, in Sambrook et al. (2001, Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory, New York), and in other virology and molecular biology manuals. Viruses that are useful as vectors include, but are not limited to, retroviruses, adenoviruses, adeno-associated viruses, herpesviruses, and lentiviruses. In general, a suitable vector contains a functional origin of replication in at least one organism, a promoter sequence, convenient restriction endonuclease sites, and one or more selected markers.

[00191] Several virus-based systems have been developed for gene transfer within mammalian cells. For example, retroviruses provide a convenient platform for gene delivery systems. A selected gene can be inserted into a vector and packaged into retroviral particles using techniques known in the art. The recombinant virus can then be isolated and delivered to the desired cells.

[00192] The present disclosure also provides expression vectors into which a nucleic acid construct of the present disclosure is inserted. In some embodiments, an inducible expression system can be used. Where inducible expression is desired, several vectors that facilitate such inducible expression are available, including, but not limited to, tetracycline-inducible vectors and tetracycline analogs, tetracycline-inducible vectors Petition 870260029606, dated 03 / 30 / 2026, page 80 / 366 / 344 tamoxifen, as well as other known inducible transcription system vectors.

[00193] The nucleic acid construct can be operatively linked to control elements that direct its transcription or expression at the nucleotide sequence in vivo. Such control elements may comprise control sequences normally associated with the selected gene (e.g., endogenous cellular control elements). Alternatively, heterologous control sequences may be used. Useful heterologous control sequences generally include those derived from sequences encoding mammalian or viral genes.Examples include, but are not limited to, the SV40 early promoter; the mouse mammary tumor virus long-terminal repeat (LTR) promoter; the adenovirus late major promoter (Ad MLP); a herpes simplex virus (HSV) promoter; a heterologous endogenous cellular promoter for the gene of interest; a cytomegalovirus (CMV) promoter such as the CMV immediate early promoter region (CMVIE); a Roux-en-Y virus (RSV) promoter; synthetic promoters; hybrid promoters; and the like. In addition, sequences derived from non-viral genes, such as the murine metallothionein gene, can also be used. Such promoter sequences are commercially available, for example, from Stratagene (San Diego, Calif.).

[00194] In some embodiments, a cell-type-specific or tissue-specific promoter can be operably linked to the nucleic acid insert encoding the heterologous gene product, and allow selective or preferential production of a gene product in one or more particular cell type(s) or tissue(s), for example, expression in cytotoxic lymphocytes. In some embodiments, an inducible promoter can be operably linked to the heterologous nucleic acid.

[00195] The vectors shown here may also include elements Petition 870260029606, dated 03 / 30 / 2026, page 81 / 366 / 344 of conventional control sequences operably linked to a nucleic acid insert (also referred to as a heterologous nucleotide sequence) in a manner that allows transcription, translation and / or expression in a cell transfected with the vector produced according to the present invention. As used herein, “operably linked” sequences include both expression control sequences that are contiguous with the gene of interest and expression control sequences that act trans or at a distance to control the gene of interest.

[00196] Expression control sequences include appropriate transcription initiation, termination, promoter, and enhancer sequences; efficient RNA processing signals such as splicing and polyadenylation (polyA) signals; sequences that stabilize cytoplasmic mRNA; sequences that enhance translation efficiency (i.e., Kozak consensus sequence); sequences that enhance protein stability; and, when desired, sequences that enhance secretion of the encoded product. A large number of expression control sequences, including selected native, constitutive, inducible, and / or tissue-specific promoters, are known in the art and can be used.

[00197] Examples of constitutive promoters include, without limitation, the LTR promoter of the retroviral Rous sarcoma virus (RSV) (optionally with RSV enhancer), the murine cell virus (MSCV) promoter, the cytomegalovirus (CMV) promoter (optionally with CMV enhancer) (see, for example, Boshart et al., Cell, 41: 521-530 (1985)), the SV40 promoter, the dihydrofoliate reductase promoter, the beta-actin promoter, the phosphoglycerol kinase (PGK) promoter, and the EF1 promoter (Invitrogen). Inducible promoters allow the regulation of gene expression and can be regulated by exogenously supplied compounds, environmental factors such as temperature, or the presence of a specific physiological state, for example, acute phase, a state of Petition 870260029606, dated 03 / 30 / 2026, page 82 / 366 / 344 particular cell differentiation, or only in replicating cells. Inducible promoters and inducible systems are available from a variety of commercial sources, including, without limitation, Invitrogen, Clonetech, and Ariad. Many other systems have been described and can be readily selected by a person with professional knowledge of the art. Examples of inducible promoters regulated by exogenously supplied compounds include the zinc-inducible sheep metallothionein promoter (MT), the dexamethasone-inducible mouse mammary tumor virus (MMTV) promoter (Dex), the T7 polymerase promoter system (WO 98 / 10088); the insect ecdysone promoter (No et al., (1996) Proc. Natl. Acad. Sci. USA, 93: 3346-3351), the tetracycline repressible system (Gossen et al., (1992) Proc. Natl. Acad. Sci. USA, 89: 5547-5551), the tetracycline inducible system (Gossen et al., (1995) Science, 268: 1766-1769, see also Harvey et al., (1998) Curr. Opin. Chem. Biol., 2: 512-518), the RU486 inducible system (Wang et al., (1997) Nat. Biotech., 15: 239-243 and Wang et al., (1997) Gene Ther., 4: 432-441) and the rapamycin-inducible system (Magari et al., (1997) J. Clin. Invest., 100: 2865-2872). Other types of inducible promoters useful in this context are those regulated by a specific physiological state, for example, temperature, acute phase, a particular cell differentiation state, or only in replicative cells. In some embodiments, a lentiviral vector containing a murine cell virus (MSCV) promoter or a human elongation factor 1 alpha (EF-1 alpha) promoter is used to express a nucleic acid encoding a PD-L1 binding protein in question as described herein, for example, in connection with any embodiment described herein.

[00198] In another embodiment, the native promoter for the nucleic acid insert will be used. The native promoter may be preferred when it is desired that the expression of the nucleic acid insert should mimic the expression Petition 870260029606, dated 03 / 30 / 2026, p. 83 / 366 / 344 native. The native promoter can be used when nucleic acid insert expression needs to be temporally or developmentally regulated, or in a tissue-specific manner, or in response to specific transcriptional stimuli. In another embodiment, other native expression control elements, such as enhancer elements, polyadenylation sites, or Kozak consensus sequences, can also be used to mimic native expression.

[00199] Another type of nucleic acid includes a gene operably linked to a tissue-specific promoter. For example, if expression in T cells and / or cytotoxic lymphocytes is desired, a promoter active in T cells and / or cytotoxic lymphocytes should be used.

[00200] In several embodiments, the vector carrying one or more nucleic acid inserts also includes selected markers or reporter genes, for example, sequences encoding resistance to geneticin, hygromycin, or puromycin, among others. Selectable reporter genes or markers can be used to signal the presence of plasmids / vectors in bacterial cells, including, for example, by examining resistance to ampicillin. Other plasmid components may include an origin of replication. The selection of these and other promoters and vector elements is conventional, and many such sequences are available (see, for example, Sambrook et al., and references cited therein).

[00201] In some cases, a nucleic acid in question includes a promoter that is operably linked to the nucleotide sequence encoding the PD-L1 binding protein in question. Suitable promoters include constitutive promoters (e.g., CMV promoter, EF1alpha promoter, MSCV, and the like) as well as inducible promoters (e.g., tetracycline and tetracycline analog inducible promoters, tamoxifen inducible promoters, and the like) and conditional promoters such as the NR4A1 promoter. In some embodiments, the vector comprises Petition 870260029606, dated 03 / 30 / 2026, page 84 / 366 / 344 transposons.

[00202] In some embodiments, the vector is pLEV having a nucleotide sequence as provided in Figure 10. In some embodiments, the pLEV vector containing the PD-L1 binding protein is provided in Figure 11. In some embodiments, the vector is SEQ ID NO: 41 (Figure 11A). In some embodiments, the vector is SEQ ID NO: 42 (Figure 11B). In some embodiments, the vector is the vector shown in Figure 16A. In some embodiments, the vector is shown in Figure 16B.

[00203] In some forms, the vector is a retroviral vector, such as a gamma-retroviral vector.

[00204] In some cases, a specific nucleic acid encoding a PD-L1 binding protein is included in a plasmid, for example, for transient expression in a eukaryotic cell, for genomic integration of an expression cassette (which includes the nucleotide sequence encoding the PD-L1 binding protein operably bound to a promoter) in a eukaryotic cell, for propagation in a bacterial cell, and so on. Cells

[00205] This disclosure provides cells that include a protein in question that specifically binds to PD-L1, and / or include a nucleic acid (e.g., as discussed above) that encodes the protein. For cells that include a nucleic acid encoding a protein in question that specifically binds to PD-L1, the nucleic acid may be retained (e.g., it may be a plasmid), or the nucleic acid may be integrated into the genome. In some embodiments, the first and second polypeptides are encoded in the same nucleic acid. In some embodiments, the first and second polypeptides are encoded in different nucleic acids. In some embodiments, the first polypeptide is encoded in one nucleic acid. In some embodiments, the second polypeptide is encoded in Petition 870260029606, dated 03 / 30 / 2026, page 85 / 366 / 344 a nucleic acid. In some embodiments, the nucleic acid is a lentiviral-based vector. In some embodiments, the viral vector is pLV4301G PDLV scFV 38A1 (SEQ ID NO: 37; Figure 11A, Figure 16A). In some embodiments, the viral vector is pLV4301G PDLV scFV 19H9 (SEQ ID NO: 38; Figure 11B, Figure 16B). In some embodiments, the viral vector is a pLEV-based viral vector. In some embodiments, the viral vector is a gamma-retroviral-based vector. In some embodiments, the viral vector is a pMSCIV-based vector. In some embodiments, the viral vector encodes 19H9. In some embodiments, the viral vector is a lentiviral-based vector encoding 19H9. In some embodiments, the viral vector is a pLEV-based viral vector encoding 19H9. In some embodiments, the viral vector encodes 38A1. In some embodiments, the viral vector is a lentiviral-based vector encoding 38A1.In some embodiments, the viral vector is a pLEV-based viral vector encoding 38A1. In some embodiments, the nucleic acid encodes a PD-L1 binding protein. In some embodiments, the PD-L1 binding protein comprises an antigen-binding moiety. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some embodiments, the increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, where an increase in the percentage of cells. Petition 870260029606, dated 03 / 30 / 2026, page 86 / 366 / 344 positive PD-L1 antibodies detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, PD-L1 binding protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, biological function includes blocking PD-1 and PD-L1 interconnection. In some embodiments, biological function includes inhibiting the PD-1 and PD-L1 signaling pathway. In some embodiments, PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the heavy and light chains are encoded the same. Petition 870260029606, dated 03 / 30 / 2026, page 87 / 366 / 344 vector. In some embodiments, the heavy and light chains are encoded in different vectors. In some embodiments, the heavy chain is encoded in a first vector. In some embodiments, the light chain is encoded in a second vector. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDRL2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDR-H1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3).In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDRH2), and SEQ ID NO: 16 (CDR-H3).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a... Petition 870260029606, dated 03 / 30 / 2026, p. 88 / 366 / 344 sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). Petition 870260029606, dated 03 / 30 / 2026, p. 89 / 366 / 344 In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.

[00206] The cells can be any convenient cell type. For example, in some cases, a cell in question is a prokaryotic cell. For example, it might be an E. coli cell used to propagate a nucleic acid (e.g., a plasmid) that encodes a protein in question. In some cases, the cell is a eukaryotic cell (e.g., a mammalian cell, a rat cell, a mouse cell, a human cell). In some cases, the cell is a cytotoxic lymphocyte. In some embodiments, the cell is a cytotoxic lymphocyte and may be referred to as a cytotoxic lymphocyte that is genetically modified to express and secrete a soluble Programmed Death Ligand 1 (PD-L1) binding protein. In such cases, the term “genetically modified” encompasses scenarios in which the nucleic acid is retained as well as scenarios in which the nucleic acid is integrated into the cell's genome.In some cases, the cell is a cytotoxic lymphocyte that is genetically modified to express and secrete a soluble Programmed Death Ligand 1 (PD-L1) binding protein, where the genetic modification is a genome modification (i.e., a nucleic acid encoding a protein in question is integrated into the cell's genome).

[00207] Cytotoxic lymphocytes that can be genetically modified to express and secrete a PD-L1 binding protein in question as described herein, for example, in connection with any embodiment described herein, include cytotoxic T cells (CTLs), natural killer T cells (NKTs), and natural killer (NK) cells. The Petition 870260029606, dated 03 / 30 / 2026, page 90 / 366 / 344 Cytotoxic lymphocytes may include, for example, peripheral blood-derived αβ TCR-positive or γδ TCR-positive T cells activated by tumor-associated antigens and / or translucent with tumor-specific chimeric antigen receptors or T cell receptors, and tumor-infiltrating lymphocytes (TILs). In some embodiments, the cytotoxic lymphocyte was modified to express and secrete a PD-L1 binding protein in question selected from the group consisting of 38A1 and 19H9. In some embodiments, the cytotoxic lymphocyte was modified to express and secrete 38A1. In some embodiments, the cytotoxic lymphocyte was modified to express and secrete 19H9.

[00208] In some embodiments, a cytotoxic T cell according to the present disclosure is a CD8+ T cell. In some embodiments, a cytotoxic T cell according to the present disclosure is a CD4+ helper T cell. In some embodiments, a cytotoxic T cell according to the present disclosure is a CD8+ T cell modified to express and secrete a PD-L1 binding protein in question as described herein. In some embodiments, a cytotoxic T cell according to the present disclosure is a CD4+ helper T cell modified to express and secrete a PD-L1 binding protein in question as described herein. In some embodiments, a cytotoxic T cell according to the present disclosure is a CD8+ T cell modified to express and secrete 38A1. In some embodiments, a cytotoxic T cell according to the present disclosure is a CD4+ helper T cell modified to express and secrete 19H9.In some embodiments, a cytotoxic T cell according to the present disclosure is a CD8+ T cell modified to express and secrete a PD-L1 binding protein. In some embodiments, a cytotoxic T cell according to the present disclosure is a CD4+ helper T cell modified to express and secrete a PD-L1 binding protein. In some embodiments, the PD-L1 binding protein is 38A1 or... Petition 870260029606, dated 03 / 30 / 2026, page 91 / 366 / 344 19H9. In some embodiments, the PD-L1 binding protein is 38A1. In some embodiments, the PD-L1 binding protein is 19H9. In some embodiments, the PD-L1 binding protein comprises an antigen-binding moiety. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some embodiments, increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the percentage of PD-L1-positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, the PD-L1-binding protein exhibits... Petition 870260029606, dated 03 / 30 / 2026, p. 92 / 366 / 344 greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, the biological function includes blocking the interconnection of PD-1 and PD-L1. In some embodiments, the biological function includes inhibiting the PD-1 and PD-L1 signaling pathway. In some embodiments, the PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4. (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDRH1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3).In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. Petition 870260029606, dated 03 / 30 / 2026, p. 93 / 366 / 344 In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (that is, conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv). Petition 870260029606, dated 03 / 30 / 2026, p. 94 / 366 / 344 comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (this It is conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.

[00209] A cytotoxic lymphocyte that can be genetically modified to express and secrete a PD-L1 binding protein in question as described herein, for example, in connection with any embodiment described herein, may express one or more activation antigens. For example, a cytotoxic lymphocyte according to the present disclosure may exhibit an increased level of expression of one or more activation antigens relative to a naive T cell. The one or more activation antigens may be selected, for example, from CD25, CD26, CD27, CD28, CD38, CD40L, CD69, CD134, CD137, BTLA, PD-1, HVEM, LIGHT, and HLA-DR. In some embodiments, the PD-L1 binding protein is 38A1 or 19H9. In some embodiments, the PD-L1 binding protein is 38A1. Petition 870260029606, dated 03 / 30 / 2026, page 95 / 366 / 344 In some embodiments, the PD-L1 binding protein is 19H9. In some embodiments, the PD-L1 binding protein comprises an antigen-binding moiety. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some embodiments, increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the percentage of PD-L1-positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, the PD-L1-binding protein exhibits greater or increased biological function in Jurkat cells when compared. Petition 870260029606, dated 03 / 30 / 2026, p. 96 / 366 / 344 with 19H9. In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, the biological function includes blocking the binding of PD-1 and PD-L1. In some embodiments, the biological function includes inhibiting the PD-1 and PD-L1 signaling pathway. In some embodiments, the PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4. (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDRH1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3).In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or... Petition 870260029606, dated 03 / 30 / 2026, page 97 / 366 / 344 fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said chain. Petition 870260029606, dated 03 / 30 / 2026, p. 98 / 366 / 344 light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1 sequence, IgG2, IgG3, or IgG4). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence).In some embodiments, the PDL1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.

[00210] In some embodiments, a cytotoxic lymphocyte that can be genetically modified to express and secrete a PD-L1 binding protein in question as described herein, for example, in connection with any embodiment described herein, includes or is genetically modified to include a specific receptor for a tumor-associated antigen, for example, a tumor-associated antigen from a tumor of a subject to be treated with a genetically modified cytotoxic lymphocyte according to the present disclosure. In some embodiments, the PD-L1 binding protein is 38A1 or 19H9. In some embodiments, the PD-L1 binding protein is 38A1. In some embodiments, the PD-L1 binding protein is 19H9. In some embodiments, the PD-L1 binding protein comprises an antigen-binding portion. In some embodiments, the 38A1 protein Petition 870260029606, dated 03 / 30 / 2026, page 99 / 366 / 344, shows greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein shows greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the 38A1 protein shows greater or increased binding capacity in melanoma when compared to 19H9.In some embodiments, increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the percentage of PD-L1-positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, the PD-L1-binding protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9. In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9.In some modalities, the biological function includes blocking the interaction of... Petition 870260029606, dated 03 / 30 / 2026, p. 100 / 366 / 344 PD-1 and PD-L1. In some embodiments, the biological function includes inhibition of the PD-1 and PD-L1 signaling pathway. In some embodiments, the PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDRH1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3). In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13.In some forms, the protein... Petition 870260029606, dated 03 / 30 / 2026, p. 101 / 366 / 344 PD-L1 binding is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some... Petition 870260029606, dated 30 / 03 / 2026, p. 102 / 366 / 344 embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, the conjugation is direct.In some forms, conjugation occurs through a ligand.

[00211] A cytotoxic lymphocyte that can be genetically modified to express and secrete a PD-L1 binding protein in question as described herein, for example, in connection with any embodiment described herein, can be obtained from any tissue or fluid of a subject. For example, in some embodiments a cytotoxic lymphocyte can be obtained from the peripheral blood of a subject. In some embodiments, a cytotoxic lymphocyte that can be genetically modified to express and secrete a PD-L1 binding protein in question as described herein, for example, in connection with any embodiment described herein, is a TIL derived from a tumor of a subject. In some embodiments, the PD-L1 binding protein is 38A1 or 19H9. In some embodiments, the PD-L1 binding protein is 38A1. In some embodiments, the PD-L1 binding protein is 19H9. In some embodiments the PD-L1 binding protein comprises an antigen-binding moiety.In some forms, the 38A1 protein is exhibited. Petition 870260029606, dated 03 / 30 / 2026, page 103 / 366 / 344 shows greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some embodiments, increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the percentage of PD-L1-positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, the PD-L1-binding protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9. In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9.In some modalities, the biological function includes blocking the interaction of... Petition 870260029606, dated 03 / 30 / 2026, p. 104 / 366 / 344 PD-1 and PD-L1. In some embodiments, the biological function includes inhibition of the PD-1 and PD-L1 signaling pathway. In some embodiments, the PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDRH1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3). In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13.In some forms, the protein... Petition 870260029606, dated 03 / 30 / 2026, p. 105 / 366 / 344 PD-L1 binding is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some... Petition 870260029606, dated 30 / 03 / 2026, p. 106 / 366 / 344 embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, the conjugation is direct.In some forms, conjugation occurs through a ligand. Detectable Labels

[00212] In some embodiments, a protein in question that specifically binds to PD-L1 (i.e., a PD-L1-binding protein in question) as described herein, for example, in connection with any embodiment described herein, includes one or more detectable labels. A variety of suitable detectable labels are known in the art including, but not limited to, radioactive isotopes, fluorescents, chemiluminescents, chromophores, enzymes, enzyme substrates, enzyme cofactors, enzyme inhibitors, chromophores, dyes, metal ions, metal sols, ligands (e.g., biotin, avidin, strepavidin, or haptens) and the like. The term “fluorescent” refers to a substance or a portion thereof that is capable of exhibiting fluorescence in the detectable range. Examples of detectable labels suitable for use as components of PD-L1 binding proteins in question include affinity labels and fluorescent proteins (e.g., GFP, YFP, RFP, Petition 870260029606, dated 03 / 30 / 2026, p. 107 / 366 / 344 CFP, and related forms). In some embodiments, the PD-L1 binding protein is 38A1 or 19H9. In some embodiments, the PD-L1 binding protein is 38A1. In some embodiments, the PD-L1 binding protein is 19H9. In some embodiments, the PD-L1 binding protein comprises an antigen-binding portion. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some embodiments, increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the percentage of PD-L1-positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, assay no. Petition 870260029606, dated 03 / 30 / 2026, page 108 / 366 / 344 Example 3). In some embodiments, the PD-L1 binding protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, the biological function includes blocking the interaction of PD-1 and PD-L1. In some embodiments, the biological function includes inhibiting the PD-1 and PD-L1 signaling pathway. In some embodiments, the PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4. (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDRH1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3).In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a... Petition 870260029606, dated 03 / 30 / 2026, p. 109 / 366 / 344 sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (that is, conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. In some embodiments... Petition 870260029606, dated 03 / 30 / 2026, p. 110 / 366 100 / 344 The PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (i.e., conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.

[00213] The term “affinity label” is used here to denote a peptide segment, for example, a heterologous peptide segment that can be incorporated into a PD-L1 binding protein in question and detected using a molecule that binds the affinity label and provides a detectable signal (e.g., a fluorescent compound or protein). Primarily, any peptide or protein for which a specific antibody or other binding agent is available can be used as an affinity label. Examples of affinity labels suitable for use include, but are not limited to, a monocytic adaptor protein (MONA) binding peptide, a T7 binding peptide, a peptide of Petition 870260029606, dated 03 / 30 / 2026, page 111 / 366 101 / 344 Streptavidin binding, a polyhistidine tract, protein A (Nilsson et al., EMBO J. 4: 1075 (1985); Nilsson et al., Methods Enzymol. 198: 3 (1991)), glutathione S-transferase (Smith and Johnson, Gene 67: 31 (1988)), Glu-Glu affinity label (Grussenmeyer et al., Proc. Natl. Acad. Sci. USA 82: 7952 (1985)), substance P, FLAG peptide (Hopp et al., Biotechnology 6: 1204 (1988)), or other antigenic epitope or binding domain. See generally Ford et al., Protein Expression and Purification 2: 95 (1991). DNA molecules encoding affinity labels are available from commercial suppliers (e.g., Pharmacia Biotech, Piscataway, NJ). In some embodiments, the PD-L1 binding protein is 38A1 or 19H9. In some embodiments, the PD-L1 binding protein is 38A1. In some embodiments, the PD-L1 binding protein is 19H9. In some embodiments, the PD-L1 binding protein comprises an antigen-binding moiety.In some modalities, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some modalities, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some modalities, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some embodiments, increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the percentage of PD-L1-positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, Petition 870260029606, dated 03 / 30 / 2026, page 112 / 366 102 / 344 Increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, the PD-L1-binding protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9. In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9.In some embodiments, the biological function includes blocking the interaction of PD-1 and PD-L1. In some embodiments, the biological function includes inhibiting the PD-1 and PD-L1 signaling pathway. In some embodiments, the PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the binding protein... Petition 870260029606, dated 03 / 30 / 2026, p. 113 / 366 PD-L1 103 / 344 is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDRH1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3). In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID. Petition 870260029606, dated 03 / 30 / 2026, p. 114 / 366 104 / 344 NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PDL1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.

[00214] Any fluorescent polypeptide (also alluded to here Petition 870260029606, dated 03 / 30 / 2026, page 115 / 366 105 / 344 as a fluorescent label) well known in the art is suitable for use as a label detectable directly or in connection with an affinity label. A suitable fluorescent polypeptide will be one that can be expressed in a desired host cell, such as a bacterial cell or a mammalian cell, and readily provide a detectable signal that can be evaluated qualitatively (positive / negative) and quantitatively (e.g., comparative degrees of fluorescence). Examples of fluorescent polypeptides include, but are not limited to, yellow fluorescent protein (YFP), cyan fluorescent protein (CFP), GFP, mRFP, RFP (tdimer2), HCRED, etc., or any mutant (e.g., fluorescent proteins modified to provide enhanced fluorescence or a changed emission spectrum), analogue, or derivative thereof.Other suitable fluorescent polypeptides, as well as specific examples of those listed here, are provided in the art and are well known. In some embodiments, the PD-L1 binding protein is 38A1 or 19H9. In some embodiments, the PD-L1 binding protein is 38A1. In some embodiments, the PD-L1 binding protein is 19H9. In some embodiments, the PD-L1 binding protein comprises an antigen-binding moiety. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some embodiments, enhanced binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells. Petition 870260029606, dated 03 / 30 / 2026, page 116 / 366 106 / 344 obtained with the PD-L1 binding protein with a control antibody or by comparing with 19H9, where an increase in the percentage of PD-L1 positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, the PD-L1-binding protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9. In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9.In some embodiments, the biological function includes blocking the interaction of PD-1 and PD-L1. In some embodiments, the biological function includes inhibiting the PD-1 and PD-L1 signaling pathway. In some embodiments, the PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a... Petition 870260029606, dated 03 / 30 / 2026, p. 117 / 366 107 / 344 sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDRH1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3).In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with the SEQ ID NO: 1. Petition 870260029606, dated 03 / 30 / 2026, p. 118 / 366 108 / 344 SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (that is, conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to a... Petition 870260029606, dated 03 / 30 / 2026, p. 119 / 366 109 / 344 IgG1 sequence). In some embodiments, the PDL1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.

[00215] Biotin-based labels may also find use in the PD-L1 binding proteins in question disclosed herein. Biotinylation of molecules and substrates is well known, for example, a large number of biotinylation agents are known, including amine reactive agents and thiol reactive agents, for biotinylation of proteins, nucleic acids, carbohydrates, carboxylic acids; see, for example, chapter 4, Molecular Probes Catalog, Haugland, 6th Ed. 1996, hereby incorporated by reference. A biotinylated substrate can be detected by the binding of a detectably labeled biotin-binding partner, such as avidin or streptavidin. Similarly, a large number of haptenylation reagents are also known. In some embodiments, the PD-L1 binding protein is 38A1 or 19H9. In some embodiments, the PD-L1 binding protein is 38A1. In some embodiments, the PD-L1 binding protein is 19H9.In some embodiments, the PD-L1 binding protein comprises an antigen-binding moiety. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared with 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared with 19H9. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared with 19H9. In some embodiments, the increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells. Petition 870260029606, dated 03 / 30 / 2026, page 120 / 366 110 / 344 obtained with the PD-L1 binding protein with a control antibody or by comparing with 19H9, where an increase in the percentage of PD-L1 positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, the PD-L1-binding protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9. In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9.In some embodiments, the biological function includes blocking the interaction of PD-1 and PD-L1. In some embodiments, the biological function includes inhibiting the PD-1 and PD-L1 signaling pathway. In some embodiments, the PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a... Petition 870260029606, dated 03 / 30 / 2026, p. 121 / 366 111 / 344 sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDRH1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3).In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with the SEQ ID NO: 1. Petition 870260029606, dated 03 / 30 / 2026, p. 122 / 366 112 / 344 SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (that is, conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to a... Petition 870260029606, dated 03 / 30 / 2026, p. 123 / 366 113 / 344 IgG1 sequence). In some embodiments, the PDL1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. Methods Adoptive Cell Transfer

[00216] Adoptive Cell Transfer (ACT) is a highly effective form of immunotherapy and involves the transfer of immune cells with antitumor activity into cancer patients. ACT is a treatment method that involves the in vitro identification of lymphocytes with antitumor activity, the in vitro expansion of these cells to large numbers, and their infusion into the cancer-bearing host. The lymphocytes used for adoptive transfer can be derived from the stroma of resected tumors (tumor-infiltrating lymphocytes or TILs). They can also be derived from blood if they are genetically engineered to express antitumor T-cell receptors (TCRs) or chimeric antigen receptors (CARs), enriched with mixed lymphocyte tumor cell cultures (MLTCs), or cloned using autologous antigen-presenting cells and tumor-derived peptides.ACT in which lymphocytes originate from the cancer-bearing host to be infused is called autologous ACT. US Publication No. 2011 / 0052530 refers to a method for performing adoptive cell therapy to promote cancer regression, primarily for the treatment of patients suffering from metastatic melanoma, which is incorporated by reference in its entirety for these methods.

[00217] In some embodiments, TILs and / or cytotoxic lymphocytes can be administered in a single dose. Such administration may be by injection, for example, intravenous injection. In some embodiments, TILs and / or cytotoxic lymphocytes can be administered in multiple doses. The dosage may be once, twice, three times, four times, five times, Petition 870260029606, dated 03 / 30 / 2026, page 124 / 366 114 / 344 six times, or more than six times a year. Dosing may be once a month, once every two weeks, once a week, or once every other day. Administration of TILs and / or cytotoxic lymphocytes may continue as long as necessary.

[00218] In some embodiments, an effective dosage of TILs and / or cytotoxic lymphocytes is about 1 x 106, about 2 x 106, about 3 x 106, about 4 x 106, about 5 x 106, about 6 x 106, about 7 x 106, about 8 x 106, about 9 x 106, about 1 x 107, about 2 x 107, about 3 x 107, about 4 x 107, about 5 x 107, about 6 x 107, about 7 2 x 108, about 3 x 108, about 4 x 108, about 5 x 108, about 6 x 108, about 7 x 108, about 8 x 108, about 9 x 108, about 1 x 109, about 2 x 109, about 3 x 109, about 4 x 109, about 5 x 109, about 6 x 109, about 7 x 109, about 8 x 109, about 9 x 109, about 1 x 1010, about 2 x 1010, about 3 x 1010, about 4 x 1010, about 5 x 1010, about 6 x 1010, about 7 x 1010, about 8 x 1010, about 9 x 10¹⁰, about 1 x 10¹¹, about 2 x 10¹¹, about 3 x 10¹¹, about 4 x 10¹¹,about 5x1011, about 6x1011, about 7x1011, about 8x1011, about 9x1011, about 1x1012, about 2x1012, about 3x1012, about 4x1012, about 5x1012, about 6x 1012, about 7x1012, about 8x1012, about 9x1012, about 1x1013, about 2x1013, about 3x1013, about 4x1013, about 5x1013, about 6x1013, about 7x1013, about 8 x 1013, and about 9 x 1013. In some modalities, an effective dosage of TILs and / or cytotoxic lymphocytes is in the range of approximately 1 x 106 to approximately 5 x 106, approximately 5 x 106 to approximately 1 x 107, approximately 1 x 107 to approximately 5 x 107, approximately 5 x 107 to approximately 1 x 108, approximately 1 x 108 to approximately 5 x 108, approximately 5 x 108 to approximately 1 x 109, approximately 1 x 109 to approximately 5 x 109, approximately 5 x 109 to approximately 1 x 1010, approximately 1 x 1010 to approximately 5 x 1010, approximately 5 x 1010 to approximately 1 x 1011, approximately 5 x 1011a about 1 x 1012, about 1 x 1012a about 5 x 1012, and about 5 x 1012a, Petition 870260029606, dated 03 / 30 / 2026, p. 125 / 366 115 / 344 approximately 1 x 1013. In some embodiments, TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete 19H9 or 38A1. In some embodiments, TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete 19H9. In some embodiments, TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete 38A1. In some embodiments, TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete 19H9 from pLV4301G PDLV scFV 19H9 (SEQ ID NO: 38; Figure 11B, Figure 16B). In some embodiments, TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete pLV4301G PDLV scFV 38A1 (SEQ ID NO: 37; Figure 11A, Figure 16A). In some embodiments, TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete a PD-L1 binding protein.In some embodiments, TIL and / or cytotoxic lymphocytes are genetically modified with a lentiviral vector to express and secrete a PD-L1 binding protein. In some embodiments, the PD-L1 binding protein comprises an antigen-binding moiety. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some embodiments, the increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, where an increase in the percentage of cells. Petition 870260029606, dated 03 / 30 / 2026, page 126 / 366 116 / 344 positive PD-L1 cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, where an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, PD-L1 binding protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, biological function includes blocking PD-1 and PD-L1 interconnection. In some embodiments, biological function includes inhibiting the PD-1 and PD-L1 signaling pathway. In some embodiments, PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the heavy and light chains are encoded the same. Petition 870260029606, dated 03 / 30 / 2026, p. 127 / 366 117 / 344 vector or nucleic acid. In some embodiments, the heavy and light chains are encoded in different vectors or nucleic acids. In some embodiments, the heavy chain is encoded in a first vector or nucleic acid. In some embodiments, the light chain is encoded in a second vector or nucleic acid. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDR-H1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3).In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv). Petition 870260029606, dated 03 / 30 / 2026, p. 128 / 366 118 / 344 comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (i.e., conjugated). to a sequence of IgG1, IgG2, IgG3, or IgG4).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a... Petition 870260029606, dated 03 / 30 / 2026, p. 129 / 366 119 / 344 sequence of IgG1, IgG2, IgG3, or IgG4 (i.e., conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4). In some embodiments, the PD-L1 binding protein is a single-stranded Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-stranded Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. Contacting cells with a specific protein.

[00219] Methods are provided for reducing the interaction between PD-L1 in a first cell (e.g., a cancerous cell such as a tumor cell) and PD-1 in another cell (e.g., an immune cell such as a T cell). Such methods may include contacting PD-L1 in the first cell with a PD-L1 binding protein (e.g., anti-PD-L1 antibody, anti-PD-L1 scFV, anti-PD-L1 maxicorpo, etc.). Any amount of reduction may be useful in some cases (depending on the context). In some cases, the interaction between PD-L1 and PD-1 is reduced by 10% or more (e.g., 20% or more, 30% or more, 50% or more, 60% or more, 75% or more, 80% or more, 85% or more, 90% or more, 95% or more, or 100%). In some embodiments, the PD-L1 binding protein is 38A1 or 19H9. In some embodiments, the PD-L1 binding protein is 38A1. In some embodiments, the PD-L1 binding protein is 19H9.In some embodiments, the PD-L1 binding protein comprises an antigen-binding moiety. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the binding capacity... Petition 870260029606, dated 03 / 30 / 2026, page 130 / 366 120 / 344 increased is measured (i) by determining the percentage of PD-L1 positive cells detected in a flow cytometry assay using a PD-L1 binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1 positive cells obtained with the PD-L1 binding protein with a control antibody or by comparing with 19H9, wherein an increase in the percentage of PD-L1 positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, the PD-L1-binding protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9. In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9.In some modalities, the biological function includes blocking the interaction of PD-1 and PD-L1. In some modalities, the biological function includes inhibiting the PD-1 and PD-L1 signaling pathway. In some modalities, the PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some modalities, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some. Petition 870260029606, dated 03 / 30 / 2026, p. 131 / 366 In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDRH1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3).In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3).In some forms, the PD-L1 binding protein is one. Petition 870260029606, dated 03 / 30 / 2026, p. 132 / 366 122 / 344 Single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (i.e., conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv). Petition 870260029606, dated 03 / 30 / 2026, p. 133 / 366 123 / 344 further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PDL1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.

[00220] Any suitable assay may be used to measure the amount of reduction and such assays will be known to a person with ordinary professional knowledge of the art.Examples of assays to measure the amount of reduction (e.g., where assays can be performed in the presence versus absence of a PD-L1 binding protein in question such as an anti-PD-L1 antibody, anti-PD-L1 scFV, anti-PD-L1 maxibody, and the like) may include, but are not limited to: measuring inhibition of cytokine production in mixed lymphocyte reaction assays (MLR assays, e.g., alloMLR assays), measuring interactions between tumor-infiltrating lymphocytes (TILs) and a tumor homolog, measuring cytotoxicity (e.g., cytotoxicity assays such as assays to measure the cytotoxic activity of a T cell to a PD-L1-expressing cell such as a cancer cell), measuring NFkB translocation to the nucleus, and measuring the signaling activity / output of the PI3K / AKT / mTOR signaling pathway (e.g., see Wang et al., Cancer Immunol Res. September 2014; 2(9)). 846-56).

[00221] Contact can occur in vitro (e.g., cells in culture). In some cases, contact is in vivo. For example, in some cases, contact involves administering a PD-L1 binding protein in question to an individual. In such cases, the method can be considered to be a treatment method (for an individual who has cancer, for an individual who has Petition 870260029606, dated 03 / 30 / 2026, page 134 / 366 124 / 344 a solid tumor, for an individual who has a chronic infection (e.g., a chronic viral infection), and the like). In some cases, contacting involves introducing into a cell (e.g., the cell expressing PD-L1, the cell expressing PD-1, or a third cell) a nucleic acid encoding a PD-L1-binding protein in question, and the cell into which the nucleic acid is introduced produces and secretes the PD-L1-binding protein. In cases where the nucleic acid is introduced into a third cell, the third cell can then be used to provide the PD-L1-binding protein through secretion. In some embodiments, where the nucleic acid is introduced into a third cell, the third cell can then be used to provide the individual or subject in need of the same PD-L1-binding protein through secretion. In some embodiments, the PD-L1-binding protein is 38A1 or 19H9.In some embodiments, the PD-L1 binding protein is 38A1. In some embodiments, the PD-L1 binding protein is 19H9. In some embodiments, the PD-L1 binding protein comprises an antigen-binding moiety. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some embodiments, the increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, where an increase in the percentage of cells. Petition 870260029606, dated 03 / 30 / 2026, pp. 135 / 366 125 / 344 positive PD-L1 cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, where an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, PD-L1 binding protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, biological function includes blocking PD-1 and PD-L1 interconnection. In some embodiments, biological function includes inhibiting the PD-1 and PD-L1 signaling pathway. In some embodiments, PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or... Petition 870260029606, dated 03 / 30 / 2026, pp. 136 / 366 126 / 344 fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDRH1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3). In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a chain. Petition 870260029606, dated 03 / 30 / 2026, pp. 137 / 366 127 / 344 heavy, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, the conjugation is direct. In some forms, conjugation occurs through a ligand.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (that is, conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In. Petition 870260029606, dated 03 / 30 / 2026, pp. 138 / 366 128 / 344 In some forms, conjugation is direct. In some forms, conjugation is through a ligand.

[00222] Therapeutic formulations comprising one or more PD-L1 binding proteins may be prepared for storage by mixing PD-L1 binding protein having the desired degree of purity with optional physiologically acceptable carriers, excipients, or stabilizers (Remington's Pharmaceutical Sciences 16th edition, Osol, A. Ed. (1980)), in the form of lyophilized formulations or aqueous solutions. The PD-L1 binding protein composition may be formulated, dosed, and administered in a manner consistent with good medical practice. Factors for consideration in this context include the particular disorder to be treated, the particular mammal to be treated, the clinical condition of the individual patient, the cause of the disorder, the site of release of the agent, the method of administration, the administration schedule, and other factors known to physicians.The “therapeutically effective amount” of PD-L1 binding protein to be administered can be controlled by such considerations, and is the minimum amount necessary to treat the patient's disease (e.g., cancer, chronic infection). In some embodiments, the PD-L1 binding protein is 38A1 or 19H9. In some embodiments, the PD-L1 binding protein is 38A1. In some embodiments, the PD-L1 binding protein is 19H9. In some embodiments, the PD-L1 binding protein comprises an antigen-binding moiety. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some modalities, the increased binding capacity is measured (i) by determining. Petition 870260029606, dated 03 / 30 / 2026, pp. 139 / 366 129 / 344 if the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or comparing with 19H9, wherein an increase in the percentage of PD-L1-positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, the PD-L1-binding protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9. In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9.In some embodiments, the biological function includes blocking the interaction of PD-1 and PD-L1. In some embodiments, the biological function includes inhibiting the PD-1 and PD-L1 signaling pathway. In some embodiments, the PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the PD-L1 binding protein... [Reference 870260029606, dated 03 / 30 / 2026, page 140 / 366.] 130 / 344 L1 is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDR-H1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3).In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv). Petition 870260029606, dated 03 / 30 / 2026, pp. 141 / 366 131 / 344 comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (i.e., conjugated). to a sequence of IgG1, IgG2, IgG3, or IgG4).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a... Petition 870260029606, dated 03 / 30 / 2026, p. 142 / 366 132 / 344 sequence of IgG1, IgG2, IgG3, or IgG4 (i.e., conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4). In some embodiments, the PD-L1 binding protein is a single-stranded Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-stranded Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.

[00223] The therapeutic dose may be at least 0.01 mg / kg of body weight, at least 0.05 mg / kg of body weight; at least 0.1 mg / kg of body weight, at least 0.5 mg / kg of body weight, at least 1 mg / kg of body weight, at least 2 mg / kg of body weight, at least 2.5 mg / kg of body weight, at least 5 mg / kg of body weight, at least 7.5 mg / kg of body weight, at least 10 mg / kg of body weight, at least 15 mg / kg of body weight, at least 20 mg / kg of body weight, at least 25 mg / kg of body weight, at least 30 mg / kg of body weight, at least 35 mg / kg of body weight, at least 40 mg / kg of body weight, at least 45 mg / kg of body weight, at least 50 mg / kg of body weight, at least 55 mg / kg of body weight, at least 60 mg / kg of body weight, at least 65 mg / kg of body weight, at least 70 mg / kg of body weight, at least 75 mg / kg of body weight, at least 80 mg / kg of body weight, at least 85 mg / kg of body weight,at least 90 mg / kg of body weight, at least 95 mg / kg of body weight, at least 100 mg / kg of body weight, at least 110 mg / kg of body weight, at least 120 mg / kg of body weight, at least 130 mg / kg of body weight, at least 140 mg / kg of body weight, at least 150 mg / kg of body weight, at least 160 mg / kg of body weight, at least 170 mg / kg of body weight, at least 180 mg / kg of body weight, at least 190 mg / kg of body weight, at least 200 mg / kg of body weight, at least 210 mg / kg of body weight, at least 220 mg / kg of, Petition 870260029606, dated 03 / 30 / 2026, pp. 143 / 366 133 / 344 body weight, at least 230 mg / kg of body weight, at least 240 mg / kg of body weight, at least 250 mg / kg of body weight, at least 260 mg / kg of body weight, at least 270 mg / kg of body weight, at least 280 mg / kg of body weight, at least 290 mg / kg of body weight, at least 300 mg / kg of body weight, at least 310 mg / kg of body weight, at least 320 mg / kg of body weight, at least 330 mg / kg of body weight, at least 340 mg / kg of body weight, at least 350 mg / kg of body weight, at least 360 mg / kg of body weight, at least 370 mg / kg of body weight, at least 380 mg / kg of body weight, at least 390 mg / kg of body weight, at least 400 mg / kg of body weight, at least 410 mg / kg of body weight, at least 420 mg / kg of body weight, at least 430 mg / kg of body weight, at least 440 mg / kg of body weight, at least 450 mg / kg of body weight, at least 460 mg / kg of body weight, at least 470 mg / kg of body weight,at least 480 mg / kg of body weight, at least 490 mg / kg of body weight, and at least 500 mg / kg of body weight. In some embodiments, the dosage is not greater than 500 mg / kg of body weight. It will be understood by a person skilled in the art that such guidelines will be adjusted with respect to the molecular weight of the active agent, for example, in the use of antibody fragments, or in the use of antibody conjugates. The dosage may also be varied with respect to localized administration, for example intranasal, inhalation, etc., or systemic administration, for example IM, IP, IV, and the like. In some embodiments, the antibody administered is 19H9 or 38A1, or a combination thereof. In some embodiments, the antibody administered is 19H9. In some embodiments, a PD-L1 binding protein is administered. In some embodiments, the PD-L1 binding protein comprises an antigen-binding moiety. In some embodiments,The antibody administered is 38A1. In some embodiments, the PD-L1 binding protein is an antibody or a fragment thereof. Petition 870260029606, dated 03 / 30 / 2026, p. 144 / 366 134 / 344 comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDR-H1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3).In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, where a. Petition 870260029606, dated 03 / 30 / 2026, pp. 145 / 366 135 / 344 said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to a sequence). Petition 870260029606, dated 03 / 30 / 2026, pp. 146 / 366 136 / 344 of IgG1, IgG2, IgG3, or IgG4). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.

[00224] PD-L1 binding protein does not need to be, but is optionally formulated with one or more agents that potentiate activity, or that otherwise increase the therapeutic effect. These are generally used at the same dosages and with the same routes of administration as previously used herein, or about 1 to 99% of the dosages hitherto used. In some embodiments, PD-L1 binding protein is 38A1 or 19H9. In some embodiments, PD-L1 binding protein is 38A1. In some embodiments, PD-L1 binding protein is 19H9. In some embodiments, PD-L1 binding protein comprises an antigen-binding moiety. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared with 19H9. In some embodiments, PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared with 19H9.In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared with 19H9. In some embodiments, the increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein there is an increase in the percentage of PD-L1-positive cells detected by flow cytometry when compared. Petition 870260029606, dated 03 / 30 / 2026, pp. 147 / 366 137 / 344 with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, the PD-L1-binding protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9.In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, the biological function includes blocking the interconnection of PD-1 and PD-L1. In some embodiments, the biological function includes inhibition of the PD-1 and PD-L1 signaling pathway. In some embodiments, the PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain. Petition 870260029606, dated 03 / 30 / 2026, pp. 148 / 366 138 / 344 wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDRH1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3). In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said chain. Petition 870260029606, dated 03 / 30 / 2026, pp. 149 / 366 139 / 344 heavy comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (that is, conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, the conjugation is direct. In some embodiments, a. Petition 870260029606, dated 03 / 30 / 2026, pp. 150 / 366 140 / 344 conjugation is through a ligand.

[00225] Acceptable carriers, excipients, or stabilizers are not toxic to receptors at the dosages and concentrations used, and include buffers such as phosphate, citrate, and other organic acids; antioxidants including ascorbic acid and methionine; preservatives (such as octadecyldimethylbenzyl ammonium chloride; hexamethonium chloride; benzalkonium chloride, benzethonium chloride; phenol, butyl or benzyl alcohol; alkyl parabens such as methyl or propyl paraben; catechol; resorcinol; cyclohexanol; 3-pentanol; and m-cresol); low molecular weight polypeptides (less than 10 residues); proteins such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, histidine, arginine, or lysine; Monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA;Sugars such as sucrose, mannitol, trehalose or sorbitol; salt-forming counterions such as sodium; metal complexes (e.g., Zn-protein complexes); and / or nonionic surfactants such as TWEEN®, PLURONICS® or polyethylene glycol (PEG). Formulations to be used for in vivo administration may be sterile. This is easily achieved by filtration through sterile filtration membranes.

[00226] PD-L1 binding protein (e.g., anti-PD-L1 antibody, anti-PD-L1 maxicorpo, anti-PD-L1 scFV, and the like) can be administered by any suitable means, including parenteral, subcutaneous, intraperitoneal, intrapulmonary, and intranasal. Parenteral infusions include intramuscular, intravenous, intra-arterial, intraperitoneal, or subcutaneous administration. Furthermore, PD-L1 binding protein (e.g., anti-PD-L1 antibody, anti-PD-L1 maxicorpo, anti-PD-L1 scFV, and the like) is appropriately administered by pulsed infusion, particularly with declining doses of the binding protein. In some cases, a binding protein Petition 870260029606, dated 03 / 30 / 2026, pp. 151 / 366 141 / 344 of the PD-L1 in question is administered systemically (e.g., IV). In some cases, a PD-L1 binding protein in question is administered locally (e.g., intratumorally, for example, via injection). In some embodiments, the PD-L1 binding protein is 38A1 or 19H9. In some embodiments, the PD-L1 binding protein is 38A1. In some embodiments, the PD-L1 binding protein is 19H9. In some embodiments, the PD-L1 binding protein comprises an antigen-binding moiety. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some forms, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some embodiments, increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the percentage of PD-L1-positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, the increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in MFI is observed. Petition 870260029606, dated 03 / 30 / 2026, pp. 152 / 366 A 142 / 344% increase in the total cell population by flow cytometry with PD-L1 binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, PD-L1 binding protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9. In some embodiments, 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9. In some embodiments, the biological function includes blocking PD-1 and PD-L1 binding. In some embodiments, the biological function includes inhibition of the PD-1 and PD-L1 signaling pathway. In some embodiments, PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared with 38A1. In some embodiments, 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared with 38A1.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4. (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDRH1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3).In some embodiments, the PD-L1 binding protein is an antibody or fragment of... Petition 870260029606, dated 03 / 30 / 2026, pp. 153 / 366 143 / 344 even comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said The heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (that is, conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the protein... Petition 870260029606, dated 03 / 30 / 2026, pp. 154 / 366 144 / 344 PD-L1 linkage is a single-stranded Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.

[00227] For the prevention or treatment of disease, the appropriate dosage of PD-L1 binding protein may depend on the type of disease being treated, as defined above, the severity and course of the disease, whether PD-L1 binding protein is administered for preventive purposes, prior therapy, the patient's clinical history and response to PD-L1 binding protein, and the attending physician's judgment. PD-L1 binding protein may be administered to the patient once or in a series of doses. Petition 870260029606, dated 03 / 30 / 2026, pp. 155 / 366 145 / 344 treatments. In some modalities, the PD-L1 binding protein is 38A1 or 19H9. In some modalities, the PD-L1 binding protein is 38A1. In some modalities, the PD-L1 binding protein is 19H9. In some modalities, the PD-L1 binding protein comprises an antigen-binding moiety. In some modalities, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some modalities, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some modalities, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some embodiments, increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the percentage of PD-L1-positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, assay no. Petition 870260029606, dated 03 / 30 / 2026, pp. 156 / 366 146 / 344 Example 3). In some embodiments, the PD-L1 binding protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, the biological function includes blocking the interaction of PD-1 and PD-L1. In some embodiments, the biological function includes inhibiting the PD-1 and PD-L1 signaling pathway. In some embodiments, the PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4. (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDRH1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3).In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a... Petition 870260029606, dated 03 / 30 / 2026, pp. 157 / 366 147 / 344 sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (that is, conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. In some embodiments... Petition 870260029606, dated 03 / 30 / 2026, pp. 158 / 366 148 / 344 The PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (i.e., conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. Adoptive Cell Transfer Methods with Genetically Modified Cytotoxic Lymphocytes to Express and Secrete a Soluble Programmed Death Ligand Binding Protein 1 (PD-L1)

[00228] Cytotoxic lymphocytes that express and secrete a PD-L1 binding protein in question as described herein, for example, in connection with any modality described herein, find use in Adoptive Cell Transfer methods, for example, in the context of treating cancer or chronic infection.

[00229] In some embodiments, suitable methods according to this disclosure include, for example, isolating cytotoxic lymphocytes. Petition 870260029606, dated 03 / 30 / 2026, pp. 159 / 366 149 / 344 as described herein, for example, in connection with any modality described herein, of a subject, for example, of a tumor or peripheral blood of a subject.

[00230] In some embodiments, suitable methods according to the present disclosure include, for example, genetically modifying cytotoxic lymphocytes by introducing into the cytotoxic lymphocytes a nucleic acid encoding a PD-L1 binding protein in question as described herein, for example, in connection with any embodiment described herein, wherein the genetically modified cytotoxic lymphocytes express and secrete the PD-L1 binding protein in question as described herein, for example, in connection with any embodiment described herein. In some embodiments, the PD-L1 binding protein is 38A1 or 19H9. In some embodiments, the PD-L1 binding protein is 38A1. In some embodiments, the PD-L1 binding protein is 19H9. In some embodiments, the PD-L1 binding protein comprises an antigen-binding portion. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared with 19H9.In some embodiments, PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared with 19H9. In some embodiments, 38A1 protein exhibits greater or increased binding capacity in melanoma when compared with 19H9. In some embodiments, increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with PD-L1 binding protein with a control antibody or by comparing with 19H9, wherein there is an increase in the percentage of PD-L1-positive cells detected by flow cytometry when compared. Petition 870260029606, dated 03 / 30 / 2026, pp. 160 / 366 150 / 344 with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, the PD-L1-binding protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9.In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, the biological function includes blocking the interconnection of PD-1 and PD-L1. In some embodiments, the biological function includes inhibition of the PD-1 and PD-L1 signaling pathway. In some embodiments, the PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain. Petition 870260029606, dated 03 / 30 / 2026, pp. 161 / 366 151 / 344 wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDRH1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3). In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1), SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said chain. Petition 870260029606, dated 03 / 30 / 2026, pp. 162 / 366 152 / 344 heavy comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising a sequence of IgG1, IgG2, IgG3, or IgG4 (that is, conjugated to a sequence of IgG1, IgG2, IgG3, or IgG4).In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, the conjugation is direct. In some embodiments, a. Petition 870260029606, dated 03 / 30 / 2026, pp. 163 / 366 153 / 344 conjugation is through a ligand.

[00231] In some embodiments, suitable methods according to the present disclosure include, for example, expanding the genetically modified cytotoxic lymphocyte to provide a population of genetically modified cytotoxic lymphocytes. In some embodiments, the TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete 19H9 or 38A1. In some embodiments, the TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete 19H9. In some embodiments, the TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete 38A1. In some embodiments, the TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete 19H9 from pLV4301G PDLV scFV 19H9 (SEQ ID NO: 38; Figure 11B, Figure 16B). In some modalities, TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete pLV4301G PDLV scFV 38A1 (SEQ ID NO: 37; Figure 11A, Figure 16A).In some embodiments, TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete a PD-L1 binding protein. In some embodiments, TIL and / or cytotoxic lymphocytes are genetically modified with a lentiviral vector to express and secrete a PD-L1 binding protein. In some embodiments, the PD-L1 binding protein comprises an antigen-binding moiety. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some modalities, the increased binding capacity is measured (i) by determining the percentage of PD-L1 positive cells detected in a flow cytometry assay using a. Petition 870260029606, dated 03 / 30 / 2026, pp. 164 / 366 154 / 344 PD-L1 binding protein labeled with or detectable by a fluorescent label, and (ii) comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or comparing with 19H9, wherein an increase in the percentage of PD-L1-positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, the PD-L1-binding protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9. In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared with 19H9.In some embodiments, the biological function includes blocking the interaction of PD-1 and PD-L1. In some embodiments, the biological function includes inhibiting the PD-1 and PD-L1 signaling pathway. In some embodiments, the PD-L1 binding protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the 19H9 protein exhibits greater or increased secretion capacity in Jurkat cells when compared to 38A1. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said... Petition 870260029606, dated 03 / 30 / 2026, pp. 165 / 366 155 / 344 The light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1, and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the heavy and light chains are encoded in the same vector or nucleic acid. In some embodiments, the heavy and light chains are encoded in different vectors or nucleic acids. In some embodiments, the heavy chain is encoded in a first vector or nucleic acid. In some embodiments, the light chain is encoded in a second vector or nucleic acid. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 2 (CDR-L1), SEQ ID NO: 3 (CDR-L2), and SEQ ID NO: 4 (CDR-L3) and said heavy chain comprises CDRs of SEQ ID NO: 6 (CDR-H1), SEQ ID NO: 7 (CDR-H2), and SEQ ID NO: 8 (CDR-H3). In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a heavy chain and a light chain, wherein said light chain comprises SEQ ID NO: 9 and said heavy chain comprises SEQ ID NO: 13.In some embodiments, the PD-L1 binding protein is an antibody or fragment thereof comprising a light chain and a heavy chain, wherein said light chain comprises CDRs of SEQ ID NO: 10 (CDR-L1). Petition 870260029606, dated 03 / 30 / 2026, pp. 166 / 366 156 / 344 SEQ ID NO: 11 (CDR-L2), and SEQ ID NO: 12 (CDR-L3) and said heavy chain comprises CDRs comprising SEQ ID NO: 14 (CDR-H1), SEQ ID NO: 15 (CDR-H2), and SEQ ID NO: 16 (CDR-H3). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 1 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises SEQ ID NO: 1 and said heavy chain comprises SEQ ID NO: 5. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 17.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 18. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 9 and said heavy chain comprises a sequence having 90%, 95%, or 98% identity with SEQ ID NO: 13.In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising a light chain and a heavy chain, wherein said light chain comprises the SEQ ID. Petition 870260029606, dated 03 / 30 / 2026, pp. 167 / 366 157 / 344 NO: 9 and said heavy chain comprises SEQ ID NO: 13. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 19. In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1, IgG2, IgG3, or IgG4 sequence (i.e., conjugated to an IgG1, IgG2, IgG3, or IgG4 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) further comprising an IgG1 sequence (i.e., conjugated to an IgG1 sequence). In some embodiments, the PD-L1 binding protein is a single-chain Fv (scFv) comprising SEQ ID NO: 20. In some embodiments, conjugation is direct. In some embodiments, conjugation is via a ligand.

[00232] In some embodiments, suitable methods according to the present disclosure include, for example, administering the genetically modified cytotoxic lymphocyte population to the subject to treat a disease or disorder of the subject, for example, cancer or a chronic infection. In some embodiments, the TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete 19H9 or 38A1. In some embodiments, the TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete 19H9. In some embodiments, the TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete 38A1. In some embodiments, the TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete 19H9 from pLV4301G PDLV scFV 19H9 (SEQ ID NO: 38; Figure 11B, Figure 16B).In some embodiments, TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete pLV4301G PDLV scFV 38A1 (SEQ ID NO: 37; Figure 11A, Figure 16A). In some embodiments, TIL and / or cytotoxic lymphocytes are genetically modified to express and secrete a PD-L1 binding protein. In some embodiments, TIL and / or cytotoxic lymphocytes are genetically modified with a lentiviral vector. Petition 870260029606, dated 03 / 30 / 2026, pp. 168 / 366 158 / 344 to express and secrete a PD-L1 binding protein. In some embodiments, the PD-L1 binding protein comprises an antigen-binding moiety. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in Jurkat cells when compared to 19H9. In some embodiments, the PD-L1 binding protein exhibits greater or increased binding capacity in melanoma when compared to 19H9. In some embodiments, the 38A1 protein exhibits greater or increased binding capacity in melanoma when compared to 19H9.In some embodiments, increased binding capacity is measured (i) by determining the percentage of PD-L1-positive cells detected in a flow cytometry assay using a PD-L1-binding protein labeled with or detectable by a fluorescent label, and (ii) by comparing the number of PD-L1-positive cells obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the percentage of PD-L1-positive cells detected by flow cytometry when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3).In some embodiments, increased binding capacity is measured (i) by determining the Mean Fluorescence Intensity (MFI) of PD-L1-positive cells in a flow cytometry assay that have been labeled with a PD-L1-binding protein labeled with or detectable by a fluorescent label and (ii) by comparing the MFI obtained with the PD-L1-binding protein with a control antibody or by comparing with 19H9, wherein an increase in the MFI of the total cell population by flow cytometry with the PD-L1-binding protein when compared with a control antibody or 19H9 indicates an increase in binding capacity (see, for example, the assay in Example 3). In some embodiments, the PD-L1-binding protein exhibits greater or increased biological function in Jurkat cells when compared. Petition 870260029606, dated 03 / 30 / 2026, pp. 169 / 366 159 / 344 with 19H9. In some embodiments, the 38A1 protein exhibits greater or increased biological function in Jurkat cells when compared to 19H9. In some embodiments, the biological function includes blocking the binding of PD-1 and PD-L1. In some embodiments, the biological function includes inhibition of the PD-1 and PD-L1 signaling pathway. In some embodiments, the...

Claims

CLAIMS 1. Protein, characterized in that it specifically binds to PD-L1 and comprises an antigen-binding moiety comprising: (a) a first polypeptide comprising the 3 amino acid sequences of the CDR defined in SEQ ID NOs: 2 to 4 and a second polypeptide comprising the 3 amino acid sequences of the CDR defined in SEQ ID NOs: 6 to 8; or (b) a first polypeptide comprising the 3 amino acid sequences of the CDR defined in SEQ ID NOs: 10 to 12, and a second polypeptide comprising the 3 amino acid sequences of the CDR defined in SEQ ID NOs: 14 to 16, wherein the first polypeptide is a light chain and the second polypeptide is a heavy chain.

2. Protein according to claim 1, characterized in that the first polypeptide comprises the amino acid sequence defined in SEQ ID NO: 1, and the second polypeptide comprises the amino acid sequence defined in SEQ ID NO:

5.

3. Protein according to claim 1, characterized in that the first polypeptide comprises the amino acid sequence defined in SEQ ID NO: 9, and the second polypeptide comprises the amino acid sequence defined in SEQ ID NO:

13.

4. Protein according to claim 1, characterized in that the protein is a single-chain antibody (scFv) and the first and second polypeptides are fused directly or through a linker to each other.

5. Protein according to claim 4, characterized in that scFv comprises the amino acid sequence defined in SEQ ID NO: 17 or SEQ ID NO:

19. Petition 870260029606, dated 03 / 30 / 2026, pp. 356 / 366 2 / 4 6. Protein according to claim 1, characterized in that the protein is a maxibody comprising an immunoglobulin Fc domain fused directly or via a ligand to the antigen-binding moiety.

7. Protein according to claim 6, characterized in that the immunoglobulin Fc domain is an IgG1 Fc domain.

8. Protein according to claim 7, characterized in that the protein comprises the amino acid sequence defined in SEQ ID NO: 18 or SEQ ID NO:

20.

9. Nucleic acid, characterized in that it comprises a nucleotide sequence encoding the protein as defined in any one of claims 1 to 8, wherein the nucleotide sequence is defined in SEQ ID NO: 37 or 38.

10. Genetically modified bacterial cell, characterized in that it expresses the protein as defined in any one of claims 1 to 8.

11. Method for manufacturing a genetically modified cytotoxic lymphocyte, the method characterized in that it comprises: genetically modifying a cytotoxic lymphocyte isolated from a tumor of an individual by introducing into the cytotoxic lymphocyte a nucleic acid, wherein the genetically modified cytotoxic lymphocyte expresses and secretes the protein as defined in any one of claims 1 to 8 that specifically binds to PD-L1; and expanding the genetically modified cytotoxic lymphocyte to provide a population of genetically modified cytotoxic lymphocytes.

12. Method according to claim 11, characterized in that the genetically modified cytotoxic lymphocyte constitutively expresses the protein that specifically binds to PD-L1. Petition 870260029606, dated 30 / 03 / 2026, pp. 357 / 366 3 / 4 13. Method according to claim 11, characterized in that the genetically modified cytotoxic lymphocyte inducibly expresses the protein that specifically binds to PD-L1.

14. Method according to claim 11, characterized in that the nucleic acid integrates into the genome of the cytotoxic lymphocyte.

15. Method according to claim 11, characterized in that the cytotoxic lymphocyte is a T cell.

16. Method according to claim 15, characterized in that the T cell is a CD8+ T cell.

17. Method according to claim 15, characterized in that the T cell is a CD4+ helper T cell.

18. Method according to claim 11, characterized in that the cytotoxic lymphocyte is a natural killer (NK) cell.

19. Method according to claim 11, characterized in that the genetically modified cytotoxic lymphocyte comprises a specific receptor for a tumor antigen.

20. Method according to claim 11, characterized in that it further comprises isolating the cytotoxic lymphocyte from the individual prior to genetic modification.

21. Method for manufacturing a genetically modified cytotoxic lymphocyte, the method characterized in that it comprises: genetically modifying a cytotoxic lymphocyte isolated from an individual with or suspected of having cancer, by introducing into the cytotoxic lymphocyte a nucleic acid, wherein the genetically modified cytotoxic lymphocyte expresses and secretes the protein as defined in any one of claims 1 to 8 that specifically binds to PD-L1. Petition 870260029606, dated 30 / 03 / 2026, pp. 358 / 366 4 / 4 22. Use of a population of cytotoxic lymphocytes obtained by the method as defined in any one of claims 11 to 21, characterized by the fact that it is used in the manufacture of a medicament for the treatment of a tumor in an individual.

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