title: Antibody repertoire development in fetal and neonatal piglets. XI. The relationship of variable heavy chain gene usage and the genomic organization of the variable heavy chain locus.
abstract: In this study, we have mapped the 3' H chain V region (V(H)) genes and those in the H chain diversity, H chain joining, and 5' portion of the H chain constant locus. We show that swine possess only two functional H chain diversity segments and only one functional H chain joining segment. These data help to explain more than a decade of observations on the preimmune repertoire of this species and reveal the vulnerability of swine to natural or designed mutational events. The results are consistent with earlier studies on the region containing Enh, Cmu, and Cdelta while revealing that the ancestral IgG3 is the most 5' Cgamma gene. We also observed a recent duplication ( approximately 1.6 million years ago) in the V(H) locus that contains six of the seven V(H) genes that comprise 75% of the preimmune repertoire. Because there are no known transfers of immune regulators or Ags that cross the placenta as in mice and humans, fetal V(H) usage must be intrinsically regulated. Therefore, we quantified V(H) usage in fetal piglets and demonstrated that usage is independent of the position of V(H) genes in the genome; the most 3' functional V(H) gene (IGHV2) is rarely used, whereas certain upstream genes (IGHV14 and IGHV15) are predominately used early in fetal liver but seldom thereafter. Similar to previous studies, three V(H) genes account for 40% of the repertoire and six for approximately 70%. This limited combinatorial diversity of the porcine V(H) repertoire further emphasizes the dependence on CDR3 diversity for generating the preimmune Ab repertoire of this species.
authors.affiliation: National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Eguchi-Ogawa
authors.forename: Nancy
authors.initials: N
authors.lastname: Wertz
authors.forename: Xiu-Zhu
authors.initials: XZ
authors.lastname: Sun
authors.forename: Francois
authors.initials: F
authors.lastname: Piumi
authors.forename: Francois
authors.initials: F
authors.lastname: Puimi
authors.forename: Hirohide
authors.initials: H
authors.lastname: Uenishi
authors.forename: Kevin
authors.initials: K
authors.lastname: Wells
authors.forename: Patrick
authors.initials: P
authors.lastname: Chardon
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Tobin
authors.forename: John E
authors.initials: JE
authors.lastname: Butler
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D002874:Chromosome Mapping; D022202:Chromosomes, Artificial, Bacterial; D005333:Fetus; D050438:Genes, Immunoglobulin Heavy Chain / Q000235:genetics*; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013552:Swine / Q000235:genetics* / Q000276:immunology
chemical_list: D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region