title: A single DH gene segment creates its own unique CDR-H3 repertoire and is sufficient for B cell development and immune function.
abstract: To test the contribution of individual D gene segments to B cell development and function, we used gene targeting to create mice that contain only DFL16.1 in the DH locus. We term this D-limited IgH allele DeltaD-DFL. Although the absolute number of IgM+IgD- B cells in the bone marrow was decreased, homozygous DeltaD-DFL BALB/c mice contained normal numbers of IgM+IgD+ B cells in bone marrow and spleen and normal numbers of B1a, B1b, and B2 cells in the peritoneal cavity. Bone marrow IgM+IgD+ B cells express a CDR-H3 repertoire similar in length and amino acid composition to the DFL16.1 subset of the wild-type BALB/c repertoire but divergent from sequences that do not contain DFL16.1. This similarity in content is the product of both germline bias and somatic selection, especially in the transition to the mature IgM+IgD+ stage of development. Serum Ig concentrations and the humoral immune response to a T-dependent Ag ([4-hydroxy-3-nitrophenyl]acetyl hapten) were nearly identical to wild-type littermate controls. A greater variance in the immune response to the T-independent Ag (alpha(1-->3)-dextran) was observed in DeltaD-DFL homozygotes, with half of the mice exhibiting levels below the range exhibited by controls. Although limited to a repertoire specific to DFL16.1, the presence of a single DH gene segment of normal sequence was sufficient for development of normal numbers of mature B cells and for robust humoral immune function.
authors.affiliation: Department of Pediatrics, University of Alabama, Birmingham, AL 35294, USA.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Schelonka
authors.forename: Ivaylo I
authors.initials: II
authors.lastname: Ivanov
authors.forename: David H
authors.initials: DH
authors.lastname: Jung
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Ippolito
authors.forename: Lars
authors.initials: L
authors.lastname: Nitschke
authors.forename: Yingxin
authors.initials: Y
authors.lastname: Zhuang
authors.forename: G Larry
authors.initials: GL
authors.lastname: Gartland
authors.forename: Jukka
authors.initials: J
authors.lastname: Pelkonen
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Alt
authors.forename: Klaus
authors.initials: K
authors.lastname: Rajewsky
authors.forename: Harry W
authors.initials: HW
authors.lastname: Schroeder
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000916:Antibody Diversity; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D001483:Base Sequence; D002454:Cell Differentiation; D022801:Complementarity Determining Regions; D004247:DNA / Q000235:genetics; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D005803:Genes, Immunoglobulin; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout
chemical_list: D022801:Complementarity Determining Regions; D007143:Immunoglobulin Heavy Chains; D004247:DNA