# US 9,872,483 B2 · Transgenic non-human mammal for producing chimeric human immunoglobulin E antibodies > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,872,483 B2 - Document ID: US9872483B2 - Status: Granted - Kind: B2 - Application number: 14/900,586 - Filed: 2014-07-03 - Published: 2016-06-09 - Granted: 2018-01-23 - Earliest claimed: 2013-07-05 - Assignees: B Cell Design; Universite De Limoges - Applicants: B Cell Design; Universite De Limoges - Inventors: Michel Cogne; Brice Laffleur; Armelle Cuvillier; Marie Bosselut - Web page: https://patentgrep.com/patent/US9872483B2 ## CPC - A01K 67/0278: Knock-in vertebrates, e.g. humanised vertebrates - C07K 16/00: Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies - A01K 2217/072: maintaining or altering function, i.e. knock in - A01K 2217/15: Animals comprising multiple alterations of the genome, by transgenesis or homologous recombination, e.g. obtained by cross-breeding - A01K 2217/206: Animal model comprising tissue-specific expression system, e.g. tissue specific expression of transgene, of Cre recombinase - A01K 2227/105: Murine - A01K 2267/01: Animal expressing industrially exogenous proteins - C07K 2317/24: containing regions, domains or residues from different species, e.g. chimeric, humanized or veneered - C12N 2800/30: Vector systems comprising sequences for excision in presence of a recombinase, e.g. loxP or FRT - C12N 2800/80: Vectors containing sites for inducing double-stranded breaks, e.g. meganuclease restriction sites - A01K: ANIMAL HUSBANDRY; AVICULTURE; APICULTURE; PISCICULTURE; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS - 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) ## Abstract The invention relates to a transgenic non-human mammal comprising human immunoglobulin mu and epsilon heavy-chain constant transgenes Cμ and Cε inserted in place of endogenous mu heavy-chain switch sequence Sμ, and its use for producing chimeric human immunoglobulin E antibodies specific for an antigen of interest. ## Claims ### Claim 1 A transgenic mouse, whose genome comprises an endogenous immunoglobulin heavy-chain locus comprising the replacement of its mu heavy-chain switch sequence Sμ by a human transgenic DNA construct comprising respectively from its 5′ to its 3′end, at least: (a) a first site-specific recombination sequence, a human immunoglobulin mu heavy-chain constant gene Cμ or a functional fragment thereof comprising at least human CH1, CH2, CH3 and CH4 exons and human membrane M1 and M2 exons, and a second site-specific recombination sequence, said first and said second recombination sequences being in the same orientation and capable of site-specific recombination, and (b) a human immunoglobulin epsilon heavy-chain constant gene Cε or a functional fragment thereof comprising at least human CH1, CH2, CH3 and CH4 exons and human membrane M1 and M2 exons, and wherein said transgenic mouse comprises endogenous B-cells which produce chimeric human immunoglobulin M (IgM) class antibodies and no endogenous IgM antibodies from said transgenic mouse, and wherein said B-cells switch chimeric human antibodies class production from immunoglobulin M to immunoglobulin E (IgE) following site-specific recombination between said first and second site-specific recombination sequences. ### Claim 2 (depends on 1) The transgenic mouse according to claim 1, wherein said site-specific recombination sequences are loxP sites of Cre recombinase. ### Claim 3 (depends on 1) The transgenic mouse according to claim 1, wherein said human transgenic DNA construct comprises the sequence SEQ ID NO: 6. ### Claim 4 (depends on 1) The transgenic mouse according to claim 1, which further comprises one or more of a human immunoglobulin light chain transgene, a human or humanized high affinity IgE receptor transgene, and a transgene encoding a recombinase specific for said recombination sequences. ### Claim 5 (depends on 1) A method for producing a chimeric human IgM antibody specific for an antigen of interest, comprising at least: a) contacting a transgenic mouse according to claim 1 with the antigen of interest to induce IgM antibody production in the B-cells of said mouse, and (b) collecting said IgM antibody. ### Claim 6 (depends on 1) A method for producing a chimeric human IgE antibody specific for an antigen of interest, comprising at least: a) contacting a transgenic mouse according to claim 1 with the antigen of interest to induce IgM antibody production in the B-cells of said mouse, (b) inducing site-specific recombination between said first and second recombination sequences of the transgenic DNA construct from the B-cells of said mouse using a recombinase specific for said recombination sequences to elicit IgE production in said B-cells, and (c) collecting said IgE antibody. ### Claim 7 (depends on 6) The method according to claim 6, wherein said site-specific recombination is induced in vitro in B-cells harvested from said transgenic mouse and further immortalized. ### Claim 8 (depends on 7) The method of claim 7, wherein the site-specific recombination is induced by introducing into the immortalized B-cells an expression vector encoding said recombinase, said recombinase, or an inductor of said recombinase. ### Claim 9 (depends on 5) The method according to claim 5, wherein the antibody is collected from B-cells that have been harvested from said mouse and further immortalized. ### Claim 10 (depends on 1) A mouse embryonic stem cell comprising the human transgenic DNA construct as defined in claim 1 inserted in its endogenous immunoglobulin heavy-chain locus in place of Sε. ### Claim 11 (depends on 1) A B-cell harvested from a mouse according to claim 1, wherein the B-cell has been immunized with an antigen of interest, wherein said B-cell produces a chimeric human IgM or IgE antibody specific for said antigen of interest, and wherein said B-cell has been immortalized. ### Claim 12 (depends on 11) The B-cell according to claim 11, wherein the B-cell is an IgE producing B-cell further comprising a site-specific recombinase-induced deletion of its human immunoglobulin mu heavy-chain constant transgene Cε. ### Claim 13 (depends on 1) A kit for producing chimeric human IgM or IgE antibodies specific for an antigen of interest, comprising at least: amouse according to claim 1, or a B-cell harvested from the mouse according to claim 1, wherein the mouse has been immunized with an antigen of interest, wherein said B-cell produces a chimeric human IgM or IgE antibody specific for said antigen of interest, and wherein said B-cell has been immortalized.