CD155-targeting antibody or antigen-binding fragment and use thereof

Abstract

The present invention relates to the technical field of immune engineering, and in particular to a CD155-targeting antibody or antigen-binding fragment and a use thereof. The antibody comprises a heavy chain variable region having at least 70% identity to a sequence shown in SEQ ID NO: 23 and a light chain variable region having at least 70% identity to a sequence shown in SEQ ID NO: 24, or a heavy chain variable region having at least 70% identity to a sequence shown in SEQ ID NO: 25 and a light chain variable region having at least 70% identity to a sequence shown in SEQ ID NO: 26. The antibody has an excellent binding capability with CD155, and CAR-T cells constructed on the basis of the antibody have a significant killing capability against tumor cells expressing CD155, as well as an obvious cellular internalization effect, the capability of promoting the cytotoxic effect of NK cells, and the capability of promoting the phagocytosis effect of macrophages, thereby exhibiting an excellent anti-tumor effect.

Description

Antibodies or antigen-binding fragments targeting CD155 and their applications Technical Field This invention belongs to the field of immune engineering technology, specifically relating to an antibody or antigen-binding fragment targeting CD155 and its application. Background Technology CD155 (also known as PVR, NECTIN-2, or Necl-5) is a multifunctional single-pass transmembrane protein that plays a crucial role in various biological processes. It plays a dual role in immune regulation. On the one hand, as a ligand for DNAM-1, CD155 can activate NK cells and T cells, promoting the killing effect of immune cells; on the other hand, by binding to immune checkpoint receptors such as TIGIT and CD96, CD155 can inhibit the activation and function of immune cells, forming an immunosuppressive tumor microenvironment. Existing research indicates that CD155 expression is typically significantly upregulated in various tumor types, becoming a common characteristic of many tumor categories. High CD155 expression regulates tumor progression by influencing processes such as cell proliferation, migration, and adhesion. Specifically, it can promote cell proliferation by activating specific signaling pathways (such as the Ras-Raf-MEK-ERK signaling pathway); simultaneously, it can interact with growth factor receptors, further affecting cell proliferation. Regarding cell migration, CD155 can participate in multiple tumor-associated signaling pathways, inducing epithelial-mesenchymal transition in tumor cells and promoting tumor cell migration. Furthermore, CD155 inhibits the activation and function of NK cells and T cells by binding to immune checkpoint receptors such as TIGIT and CD96, reducing the killing ability of immune cells against tumor cells. In addition, it can promote the recruitment and activation of immunosuppressive cells (such as MDSCs and Tregs), further exacerbating tumor immune escape. Given the crucial role of CD155 in tumor immune escape, it has become one of the important targets for tumor immunotherapy. Currently, developing antibodies specifically targeting CD155 to block its binding to immune checkpoint receptors and restore the activity and function of immune cells is one of the immunotherapy strategies targeting CD155 and its receptors. Summary of the Invention This invention develops an antibody or antigen-binding fragment targeting CD155. The antibody includes a humanized antibody that has a strong binding ability to CD155. CAT-T cells constructed based on this antibody have a significant cytotoxic ability against some tumor cells. To achieve the above objectives, the present invention can adopt the following technical solutions: This invention provides an antibody or antigen-binding fragment targeting CD155, comprising a heavy chain variable region and a light chain variable region. The heavy chain variable region includes HCDR1, HCDR2, and HCDR3, and the light chain variable region includes LCDR1, LCDR2, and LCDR3. The amino acid sequence of HCDR1 is shown in SEQ ID NO:1, the amino acid sequence of HCDR2 is shown in SEQ ID NO:2, and the amino acid sequence of HCDR3 is shown in SEQ ID NO:3. The amino acid sequence of LCDR1 is shown in SEQ ID NO:4, the amino acid sequence of LCDR2 is shown in SEQ ID NO:5, and the amino acid sequence of LCDR3 is shown in SEQ ID NO:6. Preferably, in the above-mentioned antibody or antigen-binding fragment targeting CD155, the heavy chain variable region further includes: HFR1 having at least 80% identity with the sequence shown in SEQ ID NO:7 and / or HFR2 having at least 80% identity with the sequence shown in SEQ ID NO:8 and / or HFR3 having at least 80% identity with the sequence shown in SEQ ID NO:9 and / or HFR4 having at least 80% identity with the sequence shown in SEQ ID NO:10; and / or the light chain variable region further includes: LFR1 having at least 80% identity with the sequence shown in SEQ ID NO:11 and / or LFR2 having at least 80% identity with the sequence shown in SEQ ID NO:12 and / or LFR3 having at least 80% identity with the sequence shown in SEQ ID NO:13 and / or LFR4 having at least 80% identity with the sequence shown in SEQ ID NO:14. Preferably, in the above-mentioned antibody or antigen-binding fragment targeting CD155, the heavy chain variable region further includes: HFR1 having at least 80% identity with the sequence shown in SEQ ID NO:15 and / or HFR2 having at least 80% identity with the sequence shown in SEQ ID NO:16 and / or HFR3 having at least 80% identity with the sequence shown in SEQ ID NO:17 and / or HFR4 having at least 80% identity with the sequence shown in SEQ ID NO:18; and / or the light chain variable region further includes: LFR1 having at least 80% identity with the sequence shown in SEQ ID NO:19 and / or LFR2 having at least 80% identity with the sequence shown in SEQ ID NO:20 and / or LFR3 having at least 80% identity with the sequence shown in SEQ ID NO:21 and / or LFR4 having at least 80% identity with the sequence shown in SEQ ID NO:22. Preferably, the antibody or antigen-binding fragment targeting CD155 is selected from any one of the following antibodies: (a) the antibody or antigen-binding fragment targeting CD155 includes a heavy chain variable region having at least 70% identity with the sequence shown in SEQ ID NO:23 and a light chain variable region having at least 70% identity with the sequence shown in SEQ ID NO:24; (b) the antibody targeting CD155 includes a heavy chain variable region having at least 70% identity with the sequence shown in SEQ ID NO:25 and a light chain variable region having at least 70% identity with the sequence shown in SEQ ID NO:26. Preferably, the antibody or antigen-binding fragment targeting CD155 further comprises a heavy chain constant region and / or a light chain constant region, at least a portion of which is derived from at least one of a human antibody, a primate antibody, or a mutant thereof. Preferably, both the heavy chain constant region and the light chain constant region are derived from human IgG antibodies or their mutants. Preferably, the aforementioned heavy chain constant region and light chain constant region are derived from human IgG1 antibody, human IgG4 antibody, or mutants thereof. Preferably, the heavy chain constant region contains a sequence with at least 70% identity to the sequence shown in SEQ ID NO:34, and the light chain constant region contains a sequence with at least 70% identity to the sequence shown in SEQ ID NO:35. In another aspect, the present invention provides a CAR structure comprising an antibody or antigen-binding fragment targeting CD155 as described in the present invention. Preferably, the CAR structure further includes: a hinge region having at least 80% identity with the amino acid sequence encoded by the sequence shown in SEQ ID NO:27 and / or a transmembrane region having at least 80% identity with the amino acid sequence encoded by the sequence shown in SEQ ID NO:28 and / or an intracellular signaling domain; the intracellular signaling domain includes an intracellular co-stimulatory domain having at least 80% identity with the amino acid sequence encoded by the sequence shown in SEQ ID NO:29 and an intracellular signal transduction domain having at least 80% identity with the amino acid sequence encoded by the sequence shown in SEQ ID NO:30. In another aspect, the present invention provides any of the following substances: (i) A nucleic acid molecule that encodes an antibody or antigen-binding fragment targeting CD155 in this invention or that encodes a CAR structure in this invention; (ii) an expression vector, which includes the nucleic acid molecule in (i); (iii) engineered cells, including the nucleic acid molecules in (i) and / or the expression vectors in (ii); (iv) Products that detect CD155, comprising the antibody or antigen-binding fragment targeting CD155 of the present invention; (v) A pharmaceutical composition comprising an antibody or antigen-binding fragment targeting CD155 as described in this invention and / or a CAR structure as described in this invention and / or a nucleic acid molecule in (i) and / or an expression vector in (ii) and / or an engineered cell in (iii); (vi) A pharmaceutical formulation comprising an antibody targeting CD155 of the present invention and / or an antigen-binding fragment of the present invention and / or a CAR structure of the present invention and / or a nucleic acid molecule in (i) and / or an expression vector in (ii) and / or an engineered cell in (iii) and / or a pharmaceutical composition in (v). Preferably, the above-mentioned pharmaceutical composition is a bispecific antibody, a multi-antibody, an ADC, or a fusion protein. In another aspect, the present invention provides the application of the antibody or antigen-binding fragment targeting CD155 in the preparation of a product for detecting CD155 levels. In another aspect, the present invention provides the use of the antibody or antigen-binding fragment targeting CD155 of the present invention and / or the CAR structure of the present invention and / or the nucleic acid molecule and / or expression vector and / or engineered cell of the present invention in the preparation of a drug for the prevention and / or treatment of CD155-related diseases. Preferably, CD155-related diseases include cancer, autoimmune diseases, transplant rejection, or infectious diseases. Preferably, the cancer includes at least one of acute myeloid leukemia, monocytic leukemia, melanoma, lung cancer, liver cancer, ovarian cancer, cervical cancer, pancreatic cancer, skin cancer, bladder cancer, colon cancer, breast cancer, glioma, kidney cancer, stomach cancer, esophageal cancer, oral squamous cell carcinoma, and head and neck cancer. Preferably, the above applications include one or more combinations of the following applications: (a) The application of the CD155-targeting antibody or antigen-binding fragment in this invention in mediating cell internalization; (b) The application of the antibody or antigen-binding fragment targeting CD155 in this invention in promoting the cytotoxicity of NK cells; (c) The application of the antibody or antigen-binding fragment targeting CD155 in this invention in promoting macrophage phagocytosis. The beneficial effects of this invention include at least the following: (1) The mouse antibody targeting CD155 provided by the present invention has excellent binding ability to CD155. The EC50 value of binding to CD155 recombinant protein can reach 0.969 nM, and the EC50 value of binding to CD155 overexpressing cell line can reach 21.51 nM. (2) The humanized modified antibody targeting CD155 provided by the present invention has excellent binding ability to CD155. The EC50 value of binding to CD155 recombinant protein can reach 0.315 nM, and the EC50 value of binding to CD155 overexpressing cell line can reach 12.20 nM. (3) The humanized modified antibody targeting CD155 provided by the present invention has obvious cell internalization effect, promotes NK cell killing and cytotoxicity and promotes macrophage phagocytosis. (4) The CAT-T cells constructed based on the humanized modified antibody targeting CD155 provided by this invention have significant killing ability against some tumor cells, and the killing ability is stronger than that of T cells. For example, the killing efficiency of CAT-T cells against human acute myeloid leukemia cell line can reach 62.50%, the killing efficiency against human monocytic leukemia can reach 59.32%, the killing efficiency against human liver cancer cells can reach 49.10%, the killing efficiency against human glioma cells can reach 33.52%, the killing efficiency against human breast cancer cells can reach 46.30%, the killing efficiency against human colon cancer cells can reach 41.52%, the killing efficiency against human non-small cell lung cancer cells can reach 16.58%, and the killing efficiency against human pancreatic cancer cells can reach 11.25%, etc. Attached Figure Description Figure 1 shows the expression of CD155 in various tumor tissues and normal tissues; Figure 2 shows the comparison of CD155 expression values ​​of different cell subsets in normal tissue with EGFR, ERBB2, and ROR1. Figure 3 shows the ELISA analysis of the binding of mouse antibody B03 to human CD155 protein; Figure 4 shows the binding analysis of mouse antibody B03 to cell lines overexpressing human CD155; Figure 5 shows the ELISA analysis of the binding of the human-derived modified antibody B03-1 to human CD155 protein; Figure 6 shows the binding analysis of the human-derived modified antibody B03-1 to the cell line overexpressing human CD155; Figure 7 shows the specific binding of the human-derived modified antibody B03-1 to the CD155 cell line of overexpressing monkeys. Figure 8 shows the internalization ability analysis of the human-modified antibody B03-1; Figure 9 shows the enhancement of antibody-mediated NK cell killing by the human-modified antibody B03-1. Figure 10 shows the flow cytometry analysis of macrophage phagocytosis mediated by the human-derived modified antibody B03-1 enhancing antibody. Figure 11 is a bar chart showing the macrophage phagocytosis mediated by the human-derived modified antibody B03-1 enhancing antibody. Figure 12 shows the CD155 CAR plasmid vector map. Detailed Implementation The embodiments described are provided to better illustrate the present invention, but are not intended to limit the scope of the invention to the embodiments described. Therefore, non-essential improvements and adjustments made to the embodiments by those skilled in the art based on the above description are still within the scope of protection of the present invention. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. Singular expressions include plural expressions unless they have a distinct meaning in the context. As used herein, it should be understood that terms such as “comprising,” “having,” “including,” are intended to indicate the presence of a feature, number, operation, material, or combination thereof. The terminology of the invention is disclosed in the specification and is not intended to exclude the possibility that one or more other features, numbers, operations, materials, or combinations thereof may be present or added. As used herein, “ / ” may be interpreted as “and” or “or,” depending on the context. In this invention, the term "antigen-binding fragment" refers to an antigen-binding fragment of an antibody and an antibody analogue, which typically includes at least a portion of the antigen-binding region or variable region of the parent antibody, such as one or more CDRs; the fragment of the antibody retains at least some of the binding specificity of the parent antibody. This invention provides an antibody or antigen-binding fragment targeting CD155, comprising a heavy chain variable region and a light chain variable region. The heavy chain variable region includes HCDR1, HCDR2, and HCDR3, and the light chain variable region includes LCDR1, LCDR2, and LCDR3. The amino acid sequence of HCDR1 is shown in SEQ ID NO:1, the amino acid sequence of HCDR2 is shown in SEQ ID NO:2, and the amino acid sequence of HCDR3 is shown in SEQ ID NO:3. The amino acid sequence of LCDR1 is shown in SEQ ID NO:4, the amino acid sequence of LCDR2 is shown in SEQ ID NO:5, and the amino acid sequence of LCDR3 is shown in SEQ ID NO:6. It should be noted that the antibody targeting CD155 in this invention can be any antibody form, such as a monoclonal antibody or a recombinant antibody; in terms of source, it can be a humanized antibody or an animal-derived antibody, such as a mouse, rabbit, or camel antibody; in addition, HCDR3 and LCDR3 in the above-mentioned antibodies belong to the hypervariable regions of the heavy chain variable region and the light chain variable region, and their stability is weaker than that of HCDR1 and HCDR2 as well as LCDR1 and LCDR2. In some specific examples, the heavy chain variable region of the aforementioned antibody or antigen-binding fragment targeting CD155 further includes: HFR1 having at least 80% identity with the sequence shown in SEQ ID NO:7 and / or HFR2 having at least 80% identity with the sequence shown in SEQ ID NO:8 and / or HFR3 having at least 80% identity with the sequence shown in SEQ ID NO:9 and / or HFR4 having at least 80% identity with the sequence shown in SEQ ID NO:10; and / or the light chain variable region further includes: LFR1 having at least 80% identity with the sequence shown in SEQ ID NO:11 and / or LFR2 having at least 80% identity with the sequence shown in SEQ ID NO:12 and / or LFR3 having at least 80% identity with the sequence shown in SEQ ID NO:13 and / or LFR4 having at least 80% identity with the sequence shown in SEQ ID NO:14. It should be noted that the FRs (HFR1, HFR2, HFR3, HFR4 and LFR1, LFR2, LFR3, LFR4) in the above-mentioned antibodies are backbone regions used to connect the CDR regions and are relatively stable. In addition, the sequences of the FR regions of the heavy chain and light chain and the sequences of the CDR regions can be arranged in the order FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4 to constitute the heavy chain variable region and light chain variable region of the above two antibodies, respectively. Furthermore, the at least 80% identity in this invention includes ≥80%, ≥85%, ≥90%, ≥95%, or 100% identity, etc. In addition, the above-mentioned FR sequences are derived from mouse sources and can be combined with the CDRs in this invention to form antibodies with strong affinity and high specificity targeting CD155. In some specific examples, the heavy chain variable region of the aforementioned antibody or antigen-binding fragment targeting CD155 further includes: HFR1 having at least 80% identity with the sequence shown in SEQ ID NO:15 and / or HFR2 having at least 80% identity with the sequence shown in SEQ ID NO:16 and / or HFR3 having at least 80% identity with the sequence shown in SEQ ID NO:17 and / or HFR4 having at least 80% identity with the sequence shown in SEQ ID NO:18; and / or the light chain variable region further includes: LFR1 having at least 80% identity with the sequence shown in SEQ ID NO:19 and / or LFR2 having at least 80% identity with the sequence shown in SEQ ID NO:20 and / or LFR3 having at least 80% identity with the sequence shown in SEQ ID NO:21 and / or LFR4 having at least 80% identity with the sequence shown in SEQ ID NO:22. It should be noted that the FR sequence described above is a humanized modified sequence that can be combined with the CDR region in this invention to form an antibody for recognizing CD155, which has a strong binding ability to monkey CD155. Similarly, the FR (HFR1, HFR2, HFR3, HFR4 and LFR1, LFR2, LFR3, LFR4) in the antibody described above are backbone regions used to connect the CDR region and are relatively stable. In addition, the sequences of the FR regions of the heavy chain and light chain described above and the sequences of the CDR regions can be arranged in the order of FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4. In some specific examples, the antibodies or antigen-binding fragments targeting CD155 described above are selected from any of the following antibodies: (a) An antibody or antigen-binding fragment targeting CD155 includes: a heavy chain variable region having at least 70% identity with the sequence shown in SEQ ID NO:23 and a light chain variable region having at least 70% identity with the sequence shown in SEQ ID NO:24; (b) The antibody or antigen-binding fragment targeting CD155 includes a heavy chain variable region having at least 70% identity with the sequence shown in SEQ ID NO:25 and a light chain variable region having at least 70% identity with the sequence shown in SEQ ID NO:26. It should be noted that the antibody or antigen-binding fragment targeting CD155 in this invention can preferably be an antibody composed of a heavy chain variable region consisting of the above-mentioned HCDR1 to HCDR3 and mouse-derived HFR1 to HFR4 and a light chain variable region consisting of the above-mentioned LCDR1 to LCDR3 and mouse-derived LFR1 to LFR4; similarly, it can also preferably be an antibody composed of a heavy chain variable region consisting of the above-mentioned HCDR1 to HCDR3 and humanized HFR1 to HFR4 and a light chain variable region consisting of the above-mentioned LCDR1 to LCDR3 and mouse-derived LFR1 to LFR4. In some specific examples, the aforementioned antibody or antigen-binding fragment targeting CD155 also includes a heavy chain constant region and / or a light chain constant region, at least a portion of which is derived from at least one of a human antibody, a primate antibody, or a mutant thereof. In some specific examples, the aforementioned heavy chain constant region and light chain constant region are derived from human IgG antibodies or their mutants. In some specific examples, the aforementioned heavy chain constant region and light chain constant region are derived from human IgG1 antibody, human IgG4 antibody, or their mutants. In some specific examples, the heavy chain constant region contains a sequence with at least 70% identity to the sequence shown in SEQ ID NO:34, and the light chain constant region contains a sequence with at least 70% identity to the sequence shown in SEQ ID NO:35. It should be noted that, in addition to the aforementioned heavy chain variable region and light chain variable region, the antibody or antigen-binding fragment targeting CD155 in this invention also includes a heavy chain constant region and a light chain constant region. The heavy chain constant region and light chain constant region can be human or other animal-derived (e.g., rabbit, pig, etc.), and are regions that are almost unlikely to mutate. Furthermore, the heavy and light chains of the antibody may also include a signal peptide, which can facilitate antibody transmembrane penetration; the signal peptide can be a signal peptide known in the art. This invention also provides a CAR structure comprising an antibody or antigen-binding fragment targeting CD155 as described in this invention. It should be noted that the variable region fragment of the antibody targeting CD155 in this invention can be used as the antigen recognition region of the CAR structure to form a CAR structure with other structures (such as transmembrane regions, hinge regions, or intracellular signal transduction regions); this is more conducive to the targeted killing of CD155. In some specific examples, the CAR structure described above further includes: a hinge region having at least 80% identity with the amino acid sequence encoded by the sequence shown in SEQ ID NO:27 and / or a transmembrane region and / or an intracellular signaling domain having at least 80% identity with the amino acid sequence encoded by the sequence shown in SEQ ID NO:28; the intracellular signaling domain includes an intracellular co-stimulatory domain having at least 80% identity with the amino acid sequence encoded by the sequence shown in SEQ ID NO:29 and an intracellular signal transduction domain having at least 80% identity with the amino acid sequence encoded by the sequence shown in SEQ ID NO:30. It should be noted that, as described above, the transmembrane region, hinge region, or intracellular signaling domain in this invention can preferably use the sequences described above. Similarly, at least 80% identity includes identity ≥80%, identity ≥85%, identity ≥90%, identity ≥95%, or sequence identity 100%; it should be understood that 100% identity means that the amino acid sequence of the hinge region is the amino acid sequence encoded by the sequence shown in SEQ ID NO:27, the sequence of the transmembrane region is the amino acid sequence encoded by the sequence shown in SEQ ID NO:28, and the sequence of the intracellular signaling domain is the amino acid sequence encoded by the sequences shown in SEQ ID NO:29 and SEQ ID NO:30. This invention also provides any of the following substances: (i) A nucleic acid molecule encoding an antibody or antigen-binding fragment targeting CD155 or a CAR structure as described in this invention; specifically, the nucleic acid molecule in this invention can be obtained by translating the aforementioned antibody or antigen-binding fragment or CAR structure targeting CD155 using conventional methods; alternatively, it can also be a nucleotide sequence obtained by further modifying the sequence after translating the above-mentioned amino acid sequence; the modification method is a method known in the art to increase expression efficiency or other targeted nucleotide modification methods. (ii) An expression vector comprising the nucleic acid molecule in (i); specifically, the expression vector in this invention may be selected from any one of lentiviral expression vectors, retroviral expression vectors, adenoviral expression vectors, adeno-associated virus expression vectors, DNA vectors, RNA vectors, and plasmids. Lentiviral vectors may be selected from the following group: human immunodeficiency virus 1 (HIV-1), human immunodeficiency virus 2 (HIV-2), visna-maedivirus (VMV), caprine arthritis-encephalitis virus (CAEV), equine infectious anemia virus (EIAV), feline immunodeficiency virus (FIV), bovine immunodeficiency virus (BIV), and simian immunodeficiency virus (SIV); (iii) Engineered cells, which include the nucleic acid molecules in (i) and / or the expression vector in (ii); specifically, the engineered cells in this invention can be host cells, and the above-mentioned expression vector can be introduced into the host cells to encode the antibody of this invention; when the engineered cells include a CAR structure, the engineered cells can be T cells or B cells, and the CAR structure is transduced into T cells or B cells to form CAR-T cells or CAR-B cells, which can achieve precise killing of cells that secrete CD155; (iv) Products for detecting CD155, comprising the CD155-targeting antibody or the antigen-binding fragment of the present invention; specifically, based on the fact that the CD155-targeting antibody or antigen-binding fragment can specifically bind to CD155, they can be prepared into products for detecting CD155, such as detection reagents, kits or microfluidic chips. (v) A pharmaceutical composition comprising an antibody or antigen-binding fragment targeting CD155 as described in this invention and / or a CAR structure as described in this invention and / or a nucleic acid molecule in (i) and / or an expression vector in (ii) and / or engineered cells in (iii); specifically, the antibody or antigen-binding fragment targeting CD155 as described in this invention and / or the CAR structure or nucleic acid molecule or expression vector or engineered cells as described in this invention may be combined with other active ingredients to form a pharmaceutical composition to enhance efficacy; other active ingredients may be small chemical molecules or peptides, etc. (vi) Pharmaceutical formulations comprising the antibody targeting CD155 of the present invention and / or the antigen-binding fragment of the present invention and / or the CAR structure of the present invention and / or the nucleic acid molecule in (i) and / or the expression vector in (ii) and / or the engineered cell in (iii) and / or the pharmaceutical composition in (v); specifically, the above-mentioned antibody and / or antigen-binding fragment and / or CAR structure and / or nucleic acid molecule and / or expression vector and / or engineered cell and / or pharmaceutical composition may be prepared into pharmaceutical formulations of different dosage forms by adding a pharmaceutically acceptable carrier, wherein the pharmaceutically acceptable carrier is selected according to different dosage forms in accordance with methods known in the art; dosage forms include injections, iron supplements, ointments, tablets or powders, etc.; the specific dosage form may be selected according to clinical conditions. In some specific examples, the drug composition is a bispecific antibody, a multi-antibody, an ADC, or a fusion protein. It should be noted that the antibody or antigen-binding fragment targeting CD155 in this invention can be combined with other antibodies to form bispecific or polyclonal antibodies, thereby increasing the target or therapeutic effect; in addition, the antibody or antigen-binding fragment targeting CD155 can be linked with a biologically active small molecule to form an ADC drug; furthermore, the antibody or antigen-binding fragment in this invention, as well as the bispecific and monoclonal antibodies formed therefrom, can be fused with a protein to form a fusion protein drug; the specific composition methods are known in the art. This invention also provides an application of the antibody or antigen-binding fragment targeting CD155 in the preparation of a product for detecting CD155 levels. This invention also provides the application of the antibody or antigen-binding fragment targeting CD155 and / or the CAR structure and / or the nucleic acid molecule and / or expression vector and / or engineered cells in the preparation of a drug for the prevention and / or treatment of CD155-related diseases. In some specific examples, CD155-related diseases include cancer, autoimmune diseases, transplant rejection, or infectious diseases. In some specific examples, cancer includes at least one of acute myeloid leukemia, monocytic leukemia, melanoma, lung cancer, liver cancer, ovarian cancer, cervical cancer, pancreatic cancer, skin cancer, bladder cancer, colon cancer, breast cancer, glioma, kidney cancer, stomach cancer, esophageal cancer, oral squamous cell carcinoma, and head and neck cancer. In some specific examples, the above applications include one or more combinations of the following applications: (a) The application of the CD155-targeting antibody or antigen-binding fragment in this invention in mediating cell internalization; (b) The application of the antibody or antigen-binding fragment targeting CD155 in this invention in promoting the cytotoxicity of NK cells; (c) The application of the antibody or antigen-binding fragment targeting CD155 in this invention in promoting macrophage phagocytosis. It should be noted that cell internalization refers to the potential for ADC drug development; the three major mechanisms of antibody action—ADCC, ADCP, and CDC—are key to the therapeutic effects of antibody drugs. The ADCC mechanism involves antibody-dependent cell-mediated cytotoxicity, indirectly leading to the destruction of target cells by the binding of the antibody's Fc fragment to FcRs on the surface of killer cells (i.e., the cytotoxic effect of NK cells); the ADCP mechanism involves monocytes, macrophages, neutrophils, and dendritic cells mediating phagocytosis by expressing specific FcγRs (the role of macrophages in phagocytosis). To better understand the present invention, specific examples are provided below to further illustrate the content of the present invention, but the content of the present invention is not limited to the examples below. I. CD155 expression in different tumors and flow cytometry detection of tumor cells The expression of CD155 in various tumor tissues and normal tissues was analyzed using the website http: / / gepia.cancer-pku.cn / index.html. As shown in Figure 1, CD155 was significantly expressed in multiple tumor tissues. Subsequently, the CD155 expression in normal tissues was analyzed and compared with EGFR, ERBB2, and ROR1. A dataset of 49 single-cell RNA sequencing (scRNA-seq) data from 9 healthy tissues was merged. The scRNA-seq data were analyzed using the R package Seurat (version 4.2.0). Strict quality control was implemented based on three indicators: total UMI count, number of detected genes, and the proportion of mitochondrial gene UMI counts, to screen out low-quality cells. The following steps were then performed: Normalization: The `NormalizeData` function was used for library size correction and logarithmic transformation; Variable feature selection: The `FindVariableFeatures` function selected the top 2000 highly variable genes (hvg); Scaling: The `ScaleData` function was used to scale the HVG expression matrix; Principal Component Analysis (PCA): The scaled HVG expression matrix was subjected to PCA using `RunPCA`, retaining the top 30 components for further analysis; Dimensionality reduction: The `RunUMAP` function was used to reduce the dimensionality, embedding cells into coordinates for visualization. Cell clusters were annotated based on classic cell marker expression to identify major cell types such as T cells, B cells, NK cells, and epithelial cells. A single-gene counting matrix was created and used to plot the average expression values ​​for different cell types. All preprocessing and analysis steps were run in Python 3.9 using RStudio v4.2.0, and visualization was performed using the `pheatmap` function. As shown in Figure 2, the expression level of CD155 in normal tissues was significantly lower than that of EGFR, ERBB2 (HER2), and ROR1. EGFR, ERBB2 (HER2), and ROR1 are currently being widely used and developed in clinical practice as targets for anti-tumor drugs. II. CD155 antibody screening Using hCD155 protein (10109-H08H, Yiqiao Shenzhou) as an antigen, Balb / c mice (8 weeks old, purchased from Jiangsu Jicui Yaokang, weighing about 20g) were immunized. The immunized mice were immunized three times with purified antigen and complete Freund's adjuvant. The serum titer was detected by ELISA, and the mice with the highest serum titer of anti-human CD155 immunoglobulin were obtained. Spleen and bone marrow were harvested from mice with the highest serum titers of anti-human CD155 antibodies. Plasma cells were enriched using magnetic beads and then processed through Bruker's single-cell optical fiber platform. Plasma cells that secrete CD155 antigen were screened, and single cells were extracted. BCRs were obtained through single-cell PCR and sequenced to finally obtain the antibody sequence; specifically including: (1) The spleen was crushed and resuspended in 20 ml of PBS buffer. It was then added to a 50 ml centrifuge tube containing 10 ml of Ficoll solution (cytiva, 17144003). The tube was centrifuged at 800 g for 30 min with a vertical rotation of 1 step up and 0 step down. The lymphocyte layer was removed and mixed with cells derived from bone marrow. (2) Plasma cells were separated according to the Miltenyi CD138 Microbeads (130-098-257) instructions; the enriched plasma cells were then introduced into the Bruker single-cell optical platform. Antigen-positive plasma cells were screened according to the manufacturer's instructions, and the variable region sequence of the B03 antibody was obtained; the amino acid sequence of the heavy chain variable region is shown in SEQ ID NO:23, the amino acid sequence of the light chain variable region is shown in SEQ ID NO:24, and the specific sequences of the CDR and FR regions are shown in Table 1 below. Table 1 B03 Variable Region Sequence II. Expression and purification of full-length chimeric antibodies The full-length B03 antibody was constructed by combining the B03 variable region sequence with the heavy chain and light chain constant regions of the human antibody (the amino acid sequence of the human antibody heavy chain constant region is shown in SEQ ID NO:34, and the amino acid sequence of the human antibody light chain constant region is shown in SEQ ID NO:35), according to the method described in patent CN117264050A (according to the specification paragraph).

[0130] to

[0136] The antibody was expressed and purified using the method described in the document. After purification, 5% mannitol and 5% trehalose were added to the antibody, which was then dispensed into small portions and stored at -20°C for a long period of time. III. Analysis of the binding ability of murine chimeric antibodies (I) Antibody-antigen protein binding analysis For the antibody-antigen protein binding analysis, purified B03 antibody (full length) and hCD155-his (10109-H08H, Sinocare) recombinant protein were used in an ELISA experiment. The specific experimental steps are as follows: (1) Dilute hCD155-his with PBS to 2ug / mL, add 100uL to each well of the ELISA plate for coating, and incubate overnight at 4℃; (2) Discard the supernatant coating solution and wash with PBST; block with PBST containing 1% BSA at 37°C for 2 hours; (3) Discard the sealing solution in the well and wash with PBST; (4) Add different concentrations of BO3 antibody (full length) diluted in 1% BSA solution at a 1:3 ratio, and incubate at 37°C for 1 hour; (5) Discard the liquid and wash with PBST; add diluted HRP secondary antibody to each well and incubate at 37°C for 1 h; discard the liquid and wash with PBST. (6) Add TMB chromogenic solution to each well, react at room temperature for 10-15 min, add stop solution to terminate the reaction, read the OD value at 450 nm, plot the graph and analyze it with GraphPad Prism 9, calculate the EC50 value (when the OD450 value is half of the highest value, the concentration of the antibody is the EC50 value of the antibody. The smaller the EC50 value, the stronger the affinity of the antibody and the higher the binding ability with hCD155-his protein); the results are shown in Figure 3. The binding of BO3 to hCD155-his is concentration-dependent and the EC50 value is 0.969 nM. (II) Analysis of the antibody's ability to bind to cell lines overexpressing CD155 The ability of antibodies to bind to cell lines overexpressing CD155 was analyzed using flow cytometry. The specific steps are as follows: (1) Virus packaging and cell line construction: HEK293T cells were packaged at a ratio of 5 × 10⁻⁶ cells / cells. 5 10 cells / well were seeded into a 6-well plate and cultured overnight in DMEM medium without antibiotics; (2) Discard the culture medium before transfection and add 1 mL of fresh DMEM culture medium without antibiotics. PCDH-CMV-human CD155-EF1-RFP-T2A-Puro (hCD155 was constructed into the vector PCDH-CMV-MCS-EF1-RFP-T2A-Puro provided by Qingke Biotechnology and sent to Qingke Biotechnology for synthesis; CD155 sequence used uniprot accession: P15151, 1W-417R) and PCDH-CMV-Rhesus CD155-EF1-RFP-T2A-Puro (RCD155 was constructed into the vector PCDH-CMV-MCS-EF1-RFP-T2A-Puro provided by Qingke Biotechnology and sent to Qingke Biotechnology for synthesis; CD155 sequence used NCBI accession: NP_001036851.1, 1M-407R) were added to 200uL of serum-free DMEM medium along with pMD2G and psPAX2 vectors (3ug in total) at a mass ratio of 2:1:1. (3) After mixing, let stand for 16 minutes, and then add all the liquid to the six-well plate containing HEK293T cells. (4) After culturing for 6 hours, discard the culture medium and add fresh complete DMEM culture medium for further culturing; (5) 48 h after transfection, the cell culture supernatant was collected and filtered through a 0.45 μm filter (Millipore) to obtain the virus supernatant; (6) Add all the obtained viral supernatants to a solution containing 5×10 5 Polyglobulin (Sigma) was added to 6-well plates containing HEK293T cells at a final concentration of 4 μg / mL and cultured for 12 h. The supernatant was then discarded and fresh complete DMEM medium was added. The resulting cells were HEK293T-hCD155 and HEK293T-rCD155. (7) Dilute the HEK293T-hCD155 cells with PBS to 2×10⁻⁶. 6 Add 100 μL / tube to a 1.5 mL EP tube, add different concentrations of BO3 antibody (full length), and incubate at 4 °C for 60 min; (8) Add 1 mL of PBS to the EP tube, centrifuge at 4℃ and 3500 rpm for 5 min, discard the supernatant, and wash the precipitate with PBS again. (9) After centrifugation, discard the supernatant, resuspend the cells in 100 μL / tube of PBS, add 0.1 μL / tube of AF647 secondary antibody, and incubate at 4°C in the dark for 30 min; wash twice with PBS, centrifuge, and discard the supernatant. (10) The cells were resuspended in 200 μL / tube of PBS, and the cells were detected by flow cytometry. The results were analyzed by plotting the data using GraphPadPrism 9. As shown in Figure 4, the B03 antibody was able to bind to the CD155 overexpressing cell line in a concentration-dependent manner, with an EC50 of 21.51 nM. IV. Construction and Validation of Humanized Antibodies (I) Humanization of murine antibodies The amino acid sequences of the heavy and light chain variable regions of the mouse B03 antibody were input into the Discovery Studio modeling environment (DS, version 19.1.0.18287) for annotation of frame regions (FRs) and complementarity-determining regions (CDRs). The 3D structure of the antibody was modeled using templates from the FR and CDR regions; the optimal model was selected based on sequence similarity and energy minimization. DS identified three typical structurally determining residues and confirmed their roles in maintaining conformation through 3D visualization. Then, highly homologous human FRs were selected from the Fab sequence database, and mouse CDRs were grafted onto these human FRs. Finally, based on the typical structurally determining residues and predictions of their effects on structural stability and binding affinity, key residues for reversion were identified to obtain the variable region sequence of the humanized antibody B03-1. The amino acid sequence of its heavy chain variable region is shown in SEQ ID NO:25, and the amino acid sequence of its light chain variable region is shown in SEQ ID NO:26. The specific sequences of its CDR and FR regions are shown in Table 2 below. Table 2 B03-1 Variable Region Sequence (II) Analysis of humanized antibody binding ability (1) Analysis of the binding ability of humanized antibodies to enhance antibodies The variable region sequence of the humanized antibody B03-1 was combined with the heavy chain and light chain constant regions of the human antibody to construct the full-length B03-1 antibody (the amino acid sequence of the human antibody heavy chain constant region is shown in SEQ ID NO:34, and the amino acid sequence of the human antibody light chain constant region is shown in SEQ ID NO:35), and the expression and purification method was carried out according to the description in patent CN117264050A (following the instructions).

[0130] to

[0136] The antibody was purified using the method described above. After purification, the binding ability of the antibody to recombinant CD155 protein and CD155 overexpressing cell lines was analyzed (according to the analysis method of the B03 antibody described above). As shown in Figures 5 and 6, the humanized B03-1 antibody significantly enhanced its binding ability to CD155 protein and overexpressing cell lines, with an EC50 value of 0.315 nM for binding to recombinant CD155 protein and 12.20 nM for binding to CD155 overexpressing cell lines. (2) Analysis of the binding ability of humanized antibodies to monkey CD155 Referring to the flow cytometry analysis method in Section III (II) above for the analysis of the ability of antibodies to bind to CD155-overexpressing cell lines, 293T-rCD155 cells were analyzed by flow cytometry using B03-1 antibody at concentrations of 1 μg / ml, 5 μg / ml, and 10 μg / ml, respectively. As shown in Figure 7, the B03-1 antibody can significantly bind to 293T cells overexpressing monkey CD155 compared to the isotype control. (III) Validation of different effects of humanized antibody B03-1 (1) B03-1-mediated cell internalization THP-1 cells in the logarithmic growth phase were resuspended in 1 μg / ml of full-length B03-1 antibody and incubated for 1 h. They were then incubated at 37°C for 0 h, 1 h, 3 h, and 6 h, respectively. After internalization, the cells were fixed and incubated with 2 μg / ml of human IgG (Jackson, 109-606-170) for 1 h. After washing twice with PBS, the cells were analyzed by flow cytometry. The results are shown in Figure 8. As time increased, the cell surface fluorescence gradually decreased, indicating that the surface antigen-antibody complex was gradually internalized. (2) B03-1-mediated ADCC NK cells were isolated from peripheral blood of healthy blood donors using a human NK cell enrichment kit (Miltenyi, 130092657) and incubated overnight in medium containing 500 IU / ml human recombinant IL-2 (Peprotech, 200-02). THP-1 cells in logarithmic growth phase were stained and washed with CTV (Invitrogen, C34557). NK cells and THP-1 cells were mixed at effector-to-target ratios of 4:1, 2:1, and 1:1, and cultured at 37°C for 6 hours. The killing efficiency was then assessed by flow cytometry using Annexin V-APC. The percentage of positive CTV+Annexin V-APC+ antibodies represented the cell killing efficiency. As shown in Figure 9, at different concentrations, the full-length B03-1 antibody significantly promoted the cytotoxic effect of NK cells compared to the isotype control antibody. (3) ADCP mediated by B03-1 M2 macrophages were differentiated in vitro according to the method described in Example 11 of patent CN 114423787 A. BO3-1 antibody was diluted to final concentrations of 1 μg / ml and 5 μg / ml using DMEM + 10% FBS + 1% penicillin-antibody medium. A549 cells in the logarithmic growth phase were collected, labeled with CTV dye, washed with PBS, resuspended in antibody solution, and counted at 1*102. 5 cells The final volume was 50 μL, and 5 x 10 macrophages were added. 4 cellsThe final volume was 100 μL, and the cells were incubated at 37°C for 4 hours. The cells were then resuspended and labeled with APC-labeled anti-human CD11b antibody. Flow cytometry analysis showed that total macrophages were APC-CD11b+ positive; macrophages undergoing phagocytosis were APC-CD11b+CTV+ double positive. The antibody-dependent phagocytic efficiency (%) was calculated as: (Number of macrophages undergoing phagocytosis / Total number of macrophages) * 100%. As shown in Figures 10 and 11, at different concentrations, the B03-1 antibody significantly promoted macrophage phagocytosis. V. Construction and Validation of CAR Plasmids Based on Humanized B03-1 (I) Construction of CAR plasmids targeting CD155 The B03-1 scFv antibody sequence was sent to Yunzhou Biopharmaceutical for CAR structure plasmid construction. The plasmid sequence is shown in Table 3 below, and the vector map is shown in Figure 12. The stab bacteria were obtained from the company, and plasmids were extracted by streaking and shaking according to general molecular biology methods. Viral supernatant was obtained by the virus packaging method (III (II)) described above. Table 3 CAR structural vector sequences Note: In 6272B03-1, the heavy chain variable region and the light chain variable region are connected by the (G4S)3link sequence. (II) CAR-T cell construction Lymphocytes were isolated using gradient centrifugation. After centrifugation, the second layer of white lymphocytes was collected, washed with physiological saline, and cultured in RPMI 1640 complete medium containing 10% FBS to obtain human PBMCs. The obtained PBMCs were activated for 24 hours with anti-CD3.CD28 monoclonal antibody, and the viral supernatant obtained above was added to the activated cells for infection. The CAR-T positivity rate was detected on day 3 of viral infection (using flow cytometry, detecting biotinylated human CD155 protein and streptavidin APC fluorescent secondary antibody (Biolegend, 405207). The ScFv sequence of the CAR antigen recognition region can recognize biotinylated human CD155 protein, and biotin can bind to streptavidin APC fluorescent secondary antibody; therefore, the APC fluorescence signal can be used to detect the CAR positivity rate and CAR expression intensity). Three days after viral transduction, the CAR-T positivity rate was 65.2%. (III) Detection of the in vitro killing ability of different tumor cells Using tumor cell lines MOLM13 (human acute myeloid leukemia cell line), THP-1 (human monocytic leukemia), HepG2 (human liver cancer cells), U251 (human glioma cells), MDA-MB-231 (human breast cancer cells), HT29 (human colon cancer cells), A549 (human non-small cell lung cancer cells), and Capan-1 (human pancreatic cancer cells) as positive target cells, CAR-T cells or control T cells were seeded into the target cells at an effector-target ratio of 1:2. After 4 hours, the killing efficiency was detected by flow cytometry staining for DAPI and Annexin V-APC. The percentage of positive Annexin V-APC was the cell killing efficiency. The killing efficiency of CAR-T cells against various tumor cell lines is shown in Table 4 below. Table 4 shows the killing effect of CAR-T cells on different tumor cells. As shown in Table 1 above, the constructed CD155-targeting CAR-T cells have significant killing effects on MOLM13 (human acute myeloid leukemia cell line), U937 (human histiocytic lymphoma cell line), THP-1 (human monocytic leukemia cell line), HepG2 (human liver cancer cell line), U251 (human glioma cell line), MDA-MB-231 (human breast cancer cell line), HT29 (human colon cancer cell line), A549 (human non-small cell lung cancer cell line), and Capan-1 (human pancreatic cancer cell line). Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An antibody or antigen-binding fragment targeting CD155, comprising a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises HCDR1, HCDR2, and HCDR3, and the light chain variable region comprises LCDR1, LCDR2, and LCDR3; characterized in that, The amino acid sequence of HCDR1 is shown in SEQ ID NO:1, the amino acid sequence of HCDR2 is shown in SEQ ID NO:2, and the amino acid sequence of HCDR3 is shown in SEQ ID NO:3; the amino acid sequence of LCDR1 is shown in SEQ ID NO:4, the amino acid sequence of LCDR2 is shown in SEQ ID NO:5, and the amino acid sequence of LCDR3 is shown in SEQ ID NO:

6.

2. The antibody or antigen-binding fragment targeting CD155 according to claim 1, characterized in that, The heavy chain variable region further includes: HFR1 having at least 80% identity with the sequence shown in SEQ ID NO:7 and / or HFR2 having at least 80% identity with the sequence shown in SEQ ID NO:8 and / or HFR3 having at least 80% identity with the sequence shown in SEQ ID NO:9 and / or HFR4 having at least 80% identity with the sequence shown in SEQ ID NO:10; and / or The light chain variable region further includes: LFR1 having at least 80% identity with the sequence shown in SEQ ID NO:11 and / or LFR2 having at least 80% identity with the sequence shown in SEQ ID NO:12 and / or LFR3 having at least 80% identity with the sequence shown in SEQ ID NO:13 and / or LFR4 having at least 80% identity with the sequence shown in SEQ ID NO:

14.

3. The antibody or antigen-binding fragment targeting CD155 according to claim 1, characterized in that, The heavy chain variable region further includes: HFR1 having at least 80% identity with the sequence shown in SEQ ID NO:15 and / or HFR2 having at least 80% identity with the sequence shown in SEQ ID NO:16 and / or HFR3 having at least 80% identity with the sequence shown in SEQ ID NO:17 and / or HFR4 having at least 80% identity with the sequence shown in SEQ ID NO:18; and / or The light chain variable region further includes: LFR1 having at least 80% identity with the sequence shown in SEQ ID NO:19 and / or LFR2 having at least 80% identity with the sequence shown in SEQ ID NO:20 and / or LFR3 having at least 80% identity with the sequence shown in SEQ ID NO:21 and / or LFR4 having at least 80% identity with the sequence shown in SEQ ID NO:

22.

4. The antibody or antigen-binding fragment targeting CD155 according to claim 1, characterized in that, The antibody or antigen-binding fragment targeting CD155 is selected from any of the following antibody groups: (a) The antibody targeting CD155 includes: a heavy chain variable region having at least 70% identity with the sequence shown in SEQ ID NO:23 and a light chain variable region having at least 70% identity with the sequence shown in SEQ ID NO:24; (b) The antibody targeting CD155 includes a heavy chain variable region having at least 70% identity with the sequence shown in SEQ ID NO:25 and a light chain variable region having at least 70% identity with the sequence shown in SEQ ID NO:

26.

5. The antibody or antigen-binding fragment targeting CD155 according to claims 1 to 4, characterized in that, The antibody or antigen-binding fragment targeting CD155 also includes a heavy chain constant region and / or a light chain constant region, at least a portion of which is derived from at least one of a human antibody, a primate antibody, or a mutant thereof.

6. The antibody or antigen-binding fragment targeting CD155 according to claim 5, characterized in that, Both the heavy chain constant region and the light chain constant region are derived from human IgG antibodies or their mutants.

7. The antibody or antigen-binding fragment targeting CD155 according to claim 6, characterized in that, Both the heavy chain constant region and the light chain constant region are derived from human IgG1 antibody, human IgG4 antibody or their mutants.

8. The antibody or antigen-binding fragment targeting CD155 according to claim 5, characterized in that, The heavy chain constant region contains a sequence with at least 70% identity to the sequence shown in SEQ ID NO:34, and the light chain constant region contains a sequence with at least 70% identity to the sequence shown in SEQ ID NO:

35.

9. A CAR structure, characterized in that, Includes the antibody or antigen-binding fragment targeting CD155 as described in any one of claims 1 to 8.

10. The CAR structure according to claim 9, characterized in that, The CAR structure further includes: a hinge region having at least 80% identity with the amino acid sequence encoded by the sequence shown in SEQ ID NO:27 and / or a transmembrane region having at least 80% identity with the amino acid sequence encoded by the sequence shown in SEQ ID NO:28 and / or an intracellular signaling domain; the intracellular signaling domain includes an intracellular co-stimulatory domain having at least 80% identity with the amino acid sequence encoded by the sequence shown in SEQ ID NO:29 and an intracellular signal transduction domain having at least 80% identity with the amino acid sequence encoded by the sequence shown in SEQ ID NO:

30.

11. Any of the following substances: (i) A nucleic acid molecule encoding an antibody or antigen-binding fragment targeting CD155 as described in any one of claims 1 to 8 or encoding a CAR structure as described in any one of claims 9 to 10; (ii) an expression vector, which includes the nucleic acid molecule in (i); (iii) engineered cells, including the nucleic acid molecules in (i) and / or the expression vectors in (ii); (iv) A product for detecting CD155, comprising an antibody or antigen-binding fragment targeting CD155 as described in any one of claims 1 to 8; (v) A pharmaceutical composition comprising an antibody or antigen-binding fragment targeting CD155 as claimed in any one of claims 1 to 8 and / or a CAR structure as claimed in any one of claims 9 to 10 and / or a nucleic acid molecule in (i) and / or an expression vector in (ii) and / or an engineered cell in (iii); (vi) A pharmaceutical formulation comprising an antibody or antigen-binding fragment targeting CD155 as claimed in any one of claims 1 to 8 and / or a CAR structure as claimed in any one of claims 9 to 10 and / or a nucleic acid molecule in (i) and / or an expression vector in (ii) and / or an engineered cell in (iii) and / or a pharmaceutical composition in (v).

12. The pharmaceutical composition according to claim 11, characterized in that, The drug composition is a bispecific antibody, a multi-antibody, an ADC, or a fusion protein.

13. The use of the antibody or antigen-binding fragment targeting CD155 as described in any one of claims 1 to 8 in the preparation of a product for detecting CD155 levels.

14. The use of the antibody or antigen-binding fragment targeting CD155 as described in any one of claims 1 to 8 and / or the CAR structure as described in any one of claims 9 to 10 and / or the nucleic acid molecule and / or expression vector and / or engineered cells as described in claim 11 in the preparation of a medicament for the prevention and / or treatment of CD155-related diseases.

15. The application according to claim 14, characterized in that, CD155-related diseases include cancer, autoimmune diseases, transplant rejection, or infectious diseases.

16. The application according to claim 15, characterized in that, Cancers include at least one of the following: acute myeloid leukemia, monocytic leukemia, melanoma, lung cancer, liver cancer, ovarian cancer, cervical cancer, pancreatic cancer, skin cancer, bladder cancer, colon cancer, breast cancer, glioma, kidney cancer, stomach cancer, esophageal cancer, oral squamous cell carcinoma, and head and neck cancer.

17. The application according to any one of claims 14 to 16, wherein the application comprises one or more combinations of the following applications: (a) The use of the antibody or antigen-binding fragment targeting CD155 as described in any one of claims 1 to 8 in mediating cell internalization; (b) The use of the antibody or antigen-binding fragment targeting CD155 as described in any one of claims 1 to 8 in promoting the cytotoxic effect of NK cells; (c) The use of the antibody or antigen-binding fragment targeting CD155 as described in any one of claims 1 to 8 in promoting phagocytosis by macrophages.

Images