title: Molecular characterization of human antibodies to bacterial antigens: utilization of the less frequently expressed VH2 and VH6 heavy chain variable region gene families.
abstract: Structural analysis of the human immunoglobulin repertoire holds promise for determining the basis of variable region gene usage in response to a variety of auto and exogenous antigens. Here we report the nucleotide sequences of the heavy and light chain variable regions expressed by three human monoclonal antibodies specific for two clinically relevant bacterial pathogens, Bordetella pertussis and Haemophilus influenzae type b. The cell lines were derived by in vitro stimulation of lymphocytes from spleen or tonsillar tissue, respectively, and bind to different antigens from the two organisms. The single B. pertussis antibody is of the IgM lambda isotype and utilizes the single VH6 gene segment in combination with a V lambda 2 gene and demonstrates limited somatic mutation, yet is highly indicative of an antigen-driven immune response. One H. influenzae antibody is of the IgG2 lambda isotype and expresses a VH3 gene segment with a V lambda 1 gene, while the second cell line produces an IgG3 lambda antibody expressing a combination of VH2/V lambda 3. Both molecules show evidence of somatic mutation. The D gene segments of the heavy chains vary in length and display limited sequence homology with known germline D segments. As demonstrated previously, JH4 predominates (two JH4 and one JH3) and all three utilize the J lambda 3 gene segment. In addition, we have isolated and sequenced a number of germline VH2 gene segments in an attempt to better understand the nature of the VH2 germline repertoire. In addition to contributing to the understanding of the human antibody repertoire, such clinically relevant molecules may prove to be a source of passive immunotherapy for those at risk to developing disease.
authors.affiliation: Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235.
authors.forename: J S
authors.initials: JS
authors.lastname: Andris
authors.forename: B R
authors.initials: BR
authors.lastname: Brodeur
authors.forename: J D
authors.initials: JD
authors.lastname: Capra
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000032:analysis / Q000235:genetics*; D000916:Antibody Diversity / Q000235:genetics; D000942:Antigens, Bacterial / Q000276:immunology*; D001483:Base Sequence; D001886:Bordetella pertussis / Q000276:immunology; D002460:Cell Line; D006193:Haemophilus influenzae / Q000276:immunology; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000032:analysis / Q000235:genetics*; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000032:analysis / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D012689:Sequence Homology, Nucleic Acid
chemical_list: D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region