title: Human antibody production in transgenic animals.
abstract: Fully human antibodies from transgenic animals account for an increasing number of new therapeutics. After immunization, diverse human monoclonal antibodies of high affinity can be obtained from transgenic rodents, while large animals, such as transchromosomic cattle, have produced respectable amounts of specific human immunoglobulin (Ig) in serum. Several strategies to derive animals expressing human antibody repertoires have been successful. In rodents, gene loci on bacterial artificial chromosomes or yeast artificial chromosomes were integrated by oocyte microinjection or transfection of embryonic stem (ES) cells, while ruminants were derived from manipulated fibroblasts with integrated human chromosome fragments or human artificial chromosomes. In all strains, the endogenous Ig loci have been silenced by gene targeting, either in ES or fibroblast cells, or by zinc finger technology via DNA microinjection; this was essential for optimal production. However, comparisons showed that fully human antibodies were not as efficiently produced as wild-type Ig. This suboptimal performance, with respect to immune response and antibody yield, was attributed to imperfect interaction of the human constant region with endogenous signaling components such as the Igα/β in mouse, rat or cattle. Significant improvements were obtained when the human V-region genes were linked to the endogenous CH-region, either on large constructs or, separately, by site-specific integration, which could also silence the endogenous Ig locus by gene replacement or inversion. In animals with knocked-out endogenous Ig loci and integrated large IgH loci, containing many human Vs, all D and all J segments linked to endogenous C genes, highly diverse human antibody production similar to normal animals was obtained.
authors.affiliation: Recombinant Antibody Technology Ltd., Babraham Research Campus, Babraham, Cambridge, CB22 3AT, UK, mbruggemann@ratltd.net.
authors.forename: Marianne
authors.initials: M
authors.lastname: Brüggemann
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Osborn
authors.forename: Biao
authors.initials: B
authors.lastname: Ma
authors.forename: Jasvinder
authors.initials: J
authors.lastname: Hayre
authors.forename: Suzanne
authors.initials: S
authors.lastname: Avis
authors.forename: Brian
authors.initials: B
authors.lastname: Lundstrom
authors.forename: Roland
authors.initials: R
authors.lastname: Buelow
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000378:metabolism*; D061067:Antibodies, Monoclonal, Humanized / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D005347:Fibroblasts / Q000502:physiology*; D006801:Humans; D007127:Immunoglobulin Constant Regions / Q000235:genetics; D007167:Immunotherapy; D051379:Mice; D008845:Microinjections; D009865:Oocytes / Q000502:physiology*; D015202:Protein Engineering; D051381:Rats; D013045:Species Specificity
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D007127:Immunoglobulin Constant Regions