title: A new HLA-B44 variant (B44BO [B*4408]) identified by serology.
abstract: Using HLA serology, we detected a new variant of HLA-B44- B44BO- in two families. This antigen reacts with B44 antisera and is negative with over one-third of B12 (B44, B45) sera but reacts with 50% antisera with a B62 component, especially if they contain anti-B57. The variant, B*4408, differs from the common B*4402 by 4 nucleotide substitutions in exon 2: 193, 206 and 209, which produce changes in the the alpha 1 domain at positions 41, 45 and 46 (TKE in B*4402 and AMA in B44BO); and nucleotide 213, a silent substitution. At each of these positions, B*4408 is identical to B*46 B*57 and may B*15 alleles. As anticipated from its predicted iso-electric point (5.71), one-dimensional isoelectric focusing studies showed that B44BO focuses at the same position as B*4402. The sequence and serological reactivity of this rare antigen allowed the identification of two likely epitopes shared by two different groups of HLA-B antigens.
authors.affiliation: Regional Tissue Typing Laboratory, Welsh Blood Service, Wales, United Kingdom.
authors.forename: C
authors.initials: C
authors.lastname: Darke
authors.forename: J
authors.initials: J
authors.lastname: Street
authors.forename: H
authors.initials: H
authors.lastname: Fussell
authors.forename: M
authors.initials: M
authors.lastname: Thomas
authors.forename: M
authors.initials: M
authors.lastname: Guttridge
authors.forename: T E
authors.initials: TE
authors.lastname: Goldberg
authors.forename: K L
authors.initials: KL
authors.lastname: Arnett
authors.forename: P
authors.initials: P
authors.lastname: Parham
mesh_terms: D000483:Alleles; D000906:Antibodies / Q000276:immunology; D001483:Base Sequence; D004247:DNA; D014644:Genetic Variation; D015235:HLA-B Antigens / Q000235:genetics*; D059948:HLA-B44 Antigen; D006801:Humans; D007526:Isoelectric Point; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction
chemical_list: D000906:Antibodies; D015235:HLA-B Antigens; D059948:HLA-B44 Antigen; D004247:DNA