title: High-affinity IgG antibodies develop naturally in Ig-knockout rats carrying germline human IgH/Igκ/Igλ loci bearing the rat CH region.
abstract: Mice transgenic for human Ig loci are an invaluable resource for the production of human Abs. However, such mice often do not yield human mAbs as effectively as conventional mice yield mouse mAbs. Suboptimal efficacy in delivery of human Abs might reflect imperfect interaction between the human membrane IgH chains and the mouse cellular signaling machinery. To obviate this problem, in this study we generated a humanized rat strain (OmniRat) carrying a chimeric human/rat IgH locus (comprising 22 human V(H)s, all human D and J(H) segments in natural configuration linked to the rat C(H) locus) together with fully human IgL loci (12 Vκs linked to Jκ-Cκ and 16 Vλs linked to Jλ-Cλ). The endogenous Ig loci were silenced using designer zinc finger nucleases. Breeding to homozygosity resulted in a novel transgenic rat line exclusively producing chimeric Abs with human idiotypes. B cell recovery was indistinguishable from wild-type animals, and human V(D)J transcripts were highly diverse. Following immunization, the OmniRat strain performed as efficiently as did normal rats in yielding high-affinity serum IgG. mAbs, comprising fully human variable regions with subnanomolar Ag affinity and carrying extensive somatic mutations, are readily obtainable, similarly to conventional mAbs from normal rats.
authors.affiliation: Recombinant Antibody Technology Ltd., Babraham Research Campus, Babraham, Cambridge CB22 3AT, United Kingdom.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Osborn
authors.forename: Biao
authors.initials: B
authors.lastname: Ma
authors.forename: Suzanne
authors.initials: S
authors.lastname: Avis
authors.forename: Ashleigh
authors.initials: A
authors.lastname: Binnie
authors.forename: Jeanette
authors.initials: J
authors.lastname: Dilley
authors.forename: Xi
authors.initials: X
authors.lastname: Yang
authors.forename: Kevin
authors.initials: K
authors.lastname: Lindquist
authors.forename: Séverine
authors.initials: S
authors.lastname: Ménoret
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Iscache
authors.forename: Laure-Hélène
authors.initials: LH
authors.lastname: Ouisse
authors.forename: Arvind
authors.initials: A
authors.lastname: Rajpal
authors.forename: Ignacio
authors.initials: I
authors.lastname: Anegon
authors.forename: Michael S
authors.initials: MS
authors.lastname: Neuberger
authors.forename: Roland
authors.initials: R
authors.lastname: Buelow
authors.forename: Marianne
authors.initials: M
authors.lastname: Brüggemann
mesh_terms: D000818:Animals; D001666:Binding Sites, Antibody / Q000235:genetics; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D018244:Chromosomes, Artificial, Yeast / Q000235:genetics; D005807:Genes, Overlapping / Q000235:genetics; D005854:Germ Cells / Q000276:immunology / Q000378:metabolism; D006801:Humans; D017099:IgG Deficiency / Q000235:genetics* / Q000276:immunology*; D007127:Immunoglobulin Constant Regions / Q000235:genetics*; D007074:Immunoglobulin G / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000378:metabolism*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D007146:Immunoglobulin lambda-Chains / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D051381:Rats; D055647:Rats, Transgenic
chemical_list: D007127:Immunoglobulin Constant Regions; D007074:Immunoglobulin G; D007143:Immunoglobulin Heavy Chains; D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains