title: Identification of an HLA-B7 serological variant and its characterization by sequencing based typing.
abstract: We have identified an HLA-B*07 variant allele, B*0716, in a Caucasoid cadaver kidney donor. The HLA class I type by polymerase chain reaction using sequence-specific primers (PCR-SSP) was A*01, 32; B*07, 08; Cw*07. Serological typing, using monoclonal and polyclonal anti-HLA antisera, gave disparate results for the B antigens. Monoclonal antibodies identified B7 and B8 antigens but polyclonal antisera recognised only the B8 antigen. PCR using sequencing based typing (PCR-SBT) confirmed the presence of both B*0703 and B*0801 alleles but with a mutation in one of the alleles. The HLA-B*07 allele was isolated by allele-specific PCR and was shown to have a mutation, G-->T, at 292 in exon 2. This mutation changes codon 74, which encodes aspartic acid (GAC) present in all previously identified B*07 alleles, to tyrosine (TAC) in the variant. The serological results suggest that codon 74 is a crucial part of a B7 antigen-specific epitope recognised by tissue typing polyclonal antisera.
authors.affiliation: UKTSSA, Stoke Gifford, Bristol, United Kingdom.
authors.forename: P P
authors.initials: PP
authors.lastname: Dunn
authors.forename: V
authors.initials: V
authors.lastname: Carter
authors.forename: A
authors.initials: A
authors.lastname: Dunn
authors.forename: S
authors.initials: S
authors.lastname: Day
authors.forename: S V
authors.initials: SV
authors.lastname: Fuggle
authors.forename: J
authors.initials: J
authors.lastname: Ross
authors.forename: G
authors.initials: G
authors.lastname: Cavanagh
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D017931:DNA Primers / Q000737:chemistry; D000939:Epitopes / Q000276:immunology*; D005805:Genes, MHC Class I; D015793:HLA-B7 Antigen / Q000235:genetics* / Q000276:immunology*; D006650:Histocompatibility Testing; D006801:Humans; D008969:Molecular Sequence Data; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012703:Serotyping
chemical_list: D017931:DNA Primers; D000939:Epitopes; D015793:HLA-B7 Antigen