# US 2021/0340523 A1 · Antibody library construction method and application thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0340523 A1 - Document ID: US20210340523A1 - Status: Published application - Kind: A1 - Application number: 16/973,722 - Filed: 2019-09-26 - Published: 2021-11-04 - Earliest claimed: 2018-12-21 - Assignees: Shenzhen Istirbio Co., Ltd. - Applicants: Shenzhen Istirbio Co., Ltd. - Inventors: Yongchao Yao; Youjia Li; Sha YIN; Guangjie LIU - Web page: https://patentgrep.com/patent/US20210340523A1 ## CPC - C07K 16/005: {constructed by phage libraries} - C12N 15/1037: {Screening libraries presented on the surface of microorganisms, e.g. phage display, E. coli display} - C07K 16/2803: {against the immunoglobulin superfamily} - C07K 16/303: {Liver or Pancreas} - C12N 15/1086: {Preparation or screening of expression libraries, e.g. reporter assays} - C12Q 1/6897: involving reporter genes operably linked to promoters - C07K 2317/622: Single chain antibody (scFv) - C07K 2319/035: containing a signal for targeting to the external surface of a cell, e.g. to the outer membrane of Gram negative bacteria, GPI- anchored eukaryote proteins - C07K 2319/71: containing domain for transcriptional activaation, e.g. VP16 - C12N 2740/16043: viral genome or elements thereof as genetic vector - C40B 30/04: by measuring the ability to specifically bind a target molecule, e.g. antibody-antigen binding, receptor-ligand binding - C07K: PEPTIDES (peptides in foodstuffs A23; obtaining protein compositions for foodstuffs, working-up proteins for foodstuffs A23J; preparations for medicinal purposes A61K; peptides containing beta-lactam rings C07D; cyclic dipeptides not having in their molecule any other peptide link than those which form their ring, e.g. piperazine-2,5-diones, C07D; ergot alkaloids of the cyclic peptide type C07D519/02; macromolecular compounds having statistically distributed amino acid units in their molecules, i.e. when the preparation does not provide for a specific; but for a random sequence of the amino acid units, homopolyamides and block copolyamides derived from amino acids C08G69/00; macromolecular products derived from proteins C08H1/00; preparation of glue or gelatine C09H; single cell proteins, enzymes C12N; genetic engineering processes for obtaining peptides C12N15/00; compositions for measuring or testing processes involving enzymes C12Q; investigation or analysis of biological material G01N33/00) - C12N: MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA (microbiological testing media C12Q1/00) - C12Q: MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS (immunoassay G01N33/53); COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES - C40B: COMBINATORIAL CHEMISTRY; LIBRARIES, e.g. CHEMICAL LIBRARIES (in silico combinatorial libraries of nucleic acids, proteins or peptides G16B35/00; in silico combinatorial chemistry G16C20/60) ## Abstract Disclosed by the present application are an antibody library construction method and an application thereof. The method comprises the following steps: inserting a first element and a second element into a same vector or different vectors, and transfecting the vectors into the cells to obtain an antibody expression cell library, i.e., the antibody library. The first element comprises CIS activators and selection marker genes; the second element comprises extracellular antibody library coding domain, Notch nuclear structure domain and intracellular transcription structure domain. ## Claims ### Claim 1 An antibody library construction method, comprising: inserting a first element and a second element into a same vector or different vectors, and transfecting the vector(s) into a cell to obtain an antibody expression cell library, i.e., the antibody library; wherein the first element comprises a CIS activator and a screening marker gene, and the second element comprises an extracellular antibody library coding domain, a Notch core domain and an intracellular transcription domain. ### Claim 2 (depends on 1) The method according to claim 1, wherein the screening marker gene comprises any one or a combination of at least two of a drug resistance gene, a suicide gene, a fluorescent protein gene, and a molecular tag. ### Claim 3 (depends on 2) The method according to claim 2, wherein the drug resistance gene comprises any one or a combination of at least two of a puromycin resistance gene, a neomycin resistance gene, a blasticidin resistance gene, and a hygromycin B resistance gene; the suicide gene comprises any one or a combination of at least two of a herpes simplex virus thymidine kinase gene, a cytosine deaminase gene, and an iCasp9 suicide system gene; the fluorescent protein gene comprises any one or a combination of at least two of EGFP, YFP, mCherry, DsRed, and BFP; and the molecular tag comprises any one or a combination of at least two of His-tag, Flag-tag, HA-tag, Myc-tag, and Strep-tag. ### Claim 4 (depends on 1) The method according to claim 1, wherein a screening method for the screening marker gene comprises any one or a combination of at least two of drug screening, flow cytometry detection and sorting, and magnetic-activated cell sorting. ### Claim 5 (depends on 3) The method according to claim 3, wherein a screening drug for the drug resistance gene comprises any one or a combination of at least two of puromycin, G418, blasticidin, and hygromycin B; and a screening drug for the suicide gene comprises any one or a combination of at least two of ganciclovir or FIAU, 5-fluorocytosine, AP1903, and AP20187. ### Claim 6 (depends on 1) The method according to claim 1, wherein the extracellular antibody library coding domain comprises any one or a combination of at least two of an antibody sequence, an antibody heavy chain sequence, an antibody light chain sequence, an antibody variable region sequence, a single chain antibody sequence, a single domain antibody sequence, and a Fab fragment sequence. ### Claim 7 (depends on 1) The method according to claim 1, wherein a source of the extracellular antibody library coding domain comprises any one or a combination of at least two of an immunized animal, a diseased human population, a healthy human population, a vaccinated human population, and artificial synthesis. ### Claim 8 (depends on 1) The method according to claim 1, wherein the Notch core domain comprises a human Notch, a mouse Notch, or a sequence having a similarity of not less than 85% to the human Notch or the mouse Notch; and wherein the human Notch has an amino acid sequence as shown in SEQ ID NO.1; and the mouse Notch has an amino acid sequence as shown in SEQ ID NO.2. ### Claim 9 (depends on 1) The method according to claim 1, wherein the CIS activator comprises pTet and/or UAS-pSV40. ### Claim 10 (depends on 1) The method according to claim 1, wherein the intracellular transcription domain comprises tTA and/or Ga14-VP64. ### Claim 11 (depends on 1) The method according to claim 1, wherein a method for transfecting comprises any one or a combination of at least two of viral transfection, transfection with a chemical transfection reagent, and electroporation transfection. ### Claim 12 (depends on 1) The method according to claim 1, wherein the coding domain, the domain or the gene contains any one or a combination of at least two of an amino acid sequence encoding a protein, a DNA sequence encoding a protein, and an RNA sequence encoding a protein. ### Claim 13 (depends on 1) An antibody library constructed by using the method according to claim 1. ### Claim 14 (depends on 13) A method for screening antibodies by using the antibody library according to claim 13, comprising the following steps: (1) contacting the antibody library with an antigen; and (2) screening a cell expressing a target antibody according to expression of the screening marker gene; wherein the antibody comprises a monoclonal antibody or a polyclonal antibody; and the antigen comprises any one or a combination of at least two of a wild cell, a cell transfected with a specific antigen gene, a cell bound to a specific antigen, an antigen dissolved in a culture medium, an antigen coated on a culture vessel, an antigen coated on a microsphere, and an antigen coated on a culture scaffold. ### Claim 15 (depends on 14) An antibody screened by using the method according to claim 14. ### Claim 16 A system for screening antibodies, comprising: a first element, comprising a CIS activator and a screening marker gene; and a second element, comprising a gene for encoding an extracellular antibody library coding domain, a gene for encoding a Notch core domain and a gene for encoding an intracellular transcription domain. ### Claim 17 (depends on 16) A method for screening antibodies by using the system according to claim 16, comprising: transfecting a first element and a second element into a cell, wherein the first element comprises a CIS activator and a screening marker gene, and the second element comprises a gene for encoding an extracellular antibody library coding domain, a gene for encoding a Notch core domain and a gene for encoding an intracellular transcription domain; allowing the cell to express the extracellular antibody library coding domain; contacting the cell with an antigen; and screening a cell expressing a target antibody according to expression of the screening marker gene to screen the target antibody.