141 results about "Variable region gene" patented technology

The present invention provides camel antibody libraries that maintain in vivo diversity of camelid antibody variable region genes. The in vivo diversity of antibody variable region genes can be accomplished by, for example, mixing genes derived from a plurality of animals or modifying gene amplification conditions. Conventional methods yield only VHHs with limited repertoire diversity. However, the present invention provides libraries comprising genes encoding functional VHHs with sufficient repertoire size. According to the present invention, libraries that enable to freely obtain VHHs against arbitrary antigens are provided. VHHs have excellent solubility and stability, and show a reactivity that usually cannot be expected from tetrameric IgGs.

A genetically modified non-human animal is provided, wherein the non-human animal expresses an antibody repertoire capable of pH dependent binding to antigens upon immunization. A genetically modified non-human animal is provided that expresses a single light chain variable domain derived from a single rearranged light chain variable region gene in the germline of the non-human animal, wherein the single rearranged light chain variable region gene comprises a substitution of at least one non-histidine encoding codon with a histidine encoding codon. Methods of making non-human animals that express antibodies comprising a histidine-containing universal light chain are provided.

Described herein are antibodies that bind to human tumor necrosis factor alpha (hTNFα). And list the nucleotide sequence of antibody heavy chain and light chain variable region and its derived amino acid sequence. The heavy chain and light chain variable region genes are respectively connected with the human immunoglobulin gamma 1 (hIgG1) heavy chain constant region and human kappa (k) light chain constant region genes to form a chimeric gene. Then, the vector containing the chimeric gene is introduced into the host cell line to express the antibody protein. This recombinant chimeric antibody protein can neutralize the activity of hTNFα in vitro, and is suitable for treating patients with excessive secretion of harmful hTNFα, including certain inflammations, such as rheumatoid arthritis and Crohn's disease.

A genetically modified mouse is provided, wherein the mouse is incapable of rearranging and expressing an endogenous mouse immunoglobulin light chain variable sequence, wherein the mouse expresses only one or two human light chain variable domains encoded by human immunoglobulin sequences operably linked to the mouse kappa (K) constant gene at the endogenous mouse K locus, wherein the mouse expresses a reverse chimeric antibody having a light chain variable domain derived from one of only two human light chain variable region gene segments and a mouse K constant domain,. and a human heavy chain variable domain and a mouse heavy chain constant domain, from an endogenous mouse heavy chain locus. Bispecific epitope-binding proteins that are fully human are provided, comprising two different heavy chains that associate with an identical light chain that comprises a variable domain derived from one of two different human light chain variable region gene segments.

The invention relates to gene engineering and antibody preparation and specifically discloses a preparation method and application of a high-throughput fully-humanized antibody. The preparation methodcomprises the following steps: separating peripheral blood monouclear cells; separating single cells of plasma cells or antigen-specificity memory B blymphocytes; amplifying the heavy-chain and light-chain gene variable regions of single B cell antibody by use of a primer provided by the inventor; establishing an expression system containing antibody heavy-chain and light-chain genes by use of alinear expression system containing a heavy-chain fragment or light-chain fragment constant area; finally, separating and purifying a fully humanized monoclonal antibody. By adopting the primer combination provided by the invention to amplify the genes in the antibody heavy-chain and light-chain variable areas, natural pairing of the light-chain and heavy-chain variable areas can be maintained, and the preparation method has the advantages of high gene diversity, high titer, full humanization, high antibody affinity, strong specificity, no heterologous serum reaction, no risk of propagating other infectious diseases, etc.

The invention relates to a gene assembly method of phage genetically engineered antibody library, belonging to the field of biomedical study and clinical applications. The method aims to overcome the problems of the prior art, including poor stability, low efficiency, high mutation probability and low fidelity, and indirect application to humanized single chain antibody study. The technical proposal adopted by the invention comprises the following steps of: obtaining heavy chain variable region gene and light chain variable region gene of a humanized antibody by RT-PCR, and ligating the antibody heavy chain variable region, a linker and the antibody light chain variable region with the pre-designed restriction enzyme cutting sites on two ends of primers using PCR and restriction enzyme method at the same time.

The invention discloses a B7.1-CD19scFv merge gene engineering protein and usage to treat B lymphocyte leukosis, lymph tumor, which comprises the following parts: human B7.1 external cell area, antihuman CD19 monoclonal antibody heavy chain and light chain variable area gene.

The invention discloses a single-chain antibody of broad-spectrum anti-p21ras protein and a preparation method thereof. The gene segment of the single-chain antibody is constructed by connecting light and heavy chain variable region gene segments of monoclonal antibody hybridoma cell strains of the broad-spectrum anti-p21ras protein through flexible oligonucleotide linkers; the gene segment of the single-chain antibody is connected with a phagemid expression vector to construct recombinant phagemid; the recombinant phagemid is converted into amber inhibiting colon bacillus TG1 to perform fusion expression; the positive recombinant phagemid is identified by using indirect ELISA screening through phage library exhibition; the positive recombinant phagemid is converted into non-amber inhibiting colon bacillus BL21 (DE3) to perform soluble expression of the single-chain antibody; indirect enzyme-linked immunosorbent assay and immune cell and tissue chemical experiments prove that the single-chain antibody for the soluble expression has strong binding specificity with three p21ras proteins of H-ras, K-ras and N-ras and high affinity; and the single-chain antibody is used for constructing small molecular antibodies such as intracellular antigens and the like and used for diagnosis and research of ras gene related tumors.

The invention relates to an anti-DON single-chain antibody ScFv and a preparing method and application thereof, belonging to biological product field. In the invention, variable region gene Fab section of heavy chain and light chain of antibody is cloned through a PCR method in a hybridoma cell strain McGill078 which secretes anti-DON monoclonal antibody; two genes are recombined through a gene engineering method; a prokaryotic expression plasmid vector is constructed and is transformed to Escherichia coli to express an ScFv antibody active fragment which can specifically recognize DON; and then the recombined single chain antibody ScFv is purified and renatured. The anti-DON recombined single-chain antibody ScFv has an activity for binding with DON and has the advantage of residual detection for DON owing to recognition and binding activity to DON and having antibody medicament prospect for treating DON poisoning after humanized modification; and the constructed transformation vector plasmid is easy to preserve and produce in a great quantity.

The invention relates to a preparation method for a fully-bovine-derived broad-spectrum neutralizing antibody against O-type foot-and-mouth disease viruses, belonging to the technical field of preparation of antibodies. The preparation method comprises the following steps: 1) performing primary, secondary and tertiary immunization on cattle by using O-type foot-and-mouth disease viruses; 2) screening antigen-specific individual B cells of the O-type foot-and-mouth disease viruses; 3) amplifying heavy-chain and light-chain variable genes of a bovine antibody; 4) acquiring the heavy-chain and light-chain constant region sequences of the bovine antibody; 5) preparing a full-length heavy-chain vector of a fully-bovine-derived monoclonal antibody and a full-length light-chain vector of the fully-bovine-derived monoclonal antibody; and 6) applying the full-length heavy-chain vector and the full-length light-chain vector of the fully-bovine-derived monoclonal antibody to cotransfection of cells, taking a cell culture supernatant, and purifying the supernatant so as to obtain the fully-bovine-derived broad-spectrum neutralizing antibody against O-type foot-and-mouth disease viruses. The preparation method of the invention utilizes different foot-and-mouth disease virus strains for infecting cattle and carries out screening to obtain the neutralizing antibody capable of neutralizing O-type foot-and-mouth disease viruses of three pedigrees; and the preparation method can prepare the fully-bovine-derived broad-spectrum neutralizing antibody.

The invention discloses a porcinized single-chain antibody resisting a porcine epidemic diarrhea virus and a preparation method of the porcinized single-chain antibody, and belongs to the field of biotechnology. A gene sequence of a heavy-chain variable region of the single-chain antibody is as shown in SEQ ID NO.1; the gene sequence of a light-chain variable region is as shown in SEQ ID NO.2. The single-chain antibody also comprises the gene sequence of a porcine anti-body constant region Fc segment as shown in SEQ ID NO.3, wherein the gene sequence of the heavy-chain variable region is connected with the gene sequence of the light-chain variable region through a linker sequence as shown in SEQ ID NO.4. The length of scFv-Fc is 1128bp; the molecular weight translated into a polypeptide chain is about 40kDa and is 1.4 that of natural immune globulin; the penetrability between tissues can be improved by reduction of the molecular weight; and the Elisa result shows that PEDV can be identified by the scFv-Fc.