title: Early restriction of the human antibody repertoire.
abstract: Diversification of the antibody repertoire in mammals results from a series of apparently random somatically propagated gene rearrangement and mutational events. Nevertheless, it is well known that the adult repertoire of antibody specificities is acquired in a developmentally programmed fashion. As previously shown, rearrangement of the gene segments encoding the heavy-chain variable regions (VH) of mouse antibodies is also developmentally ordered: the number of VH gene segments rearranged in B lymphocytes of fetal mice is small but increased progressively after birth. In this report, human fetal B-lineage cells were also shown to rearrange a highly restricted set of VH gene segments. In a sample of heavy-chain transcripts from a 130-day human fetus the most frequently expressed human VH element proved to be closely related to the VH element most frequently expressed in murine fetal B-lineage cells. These observations are important in understanding the development of immunocompetence.
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D001483:Base Sequence; D005333:Fetus; D005803:Genes, Immunoglobulin; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007135:Immunoglobulin Variable Region / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D012689:Sequence Homology, Nucleic Acid
chemical_list: D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region