The HLA-B73 antigen has a most unusual structure that defines a second lineage of HLA-B alleles.
The nucleotide sequence of cDNA encoding the HLA-B73 antigen was determined; it is unusually divergent, differing from other HLA-B alleles by 44-77 nucleotide substitutions. Features that distinguish the B*7301 heavy chain from other HLA-B heavy chains include multiple substitutions in the alpha 3 domain and a duplication-deletion within the transmembrane region that increases the length of B*7301 compared to other HLA-B heavy chains. The duplication-deletion is shared with subsets of B alleles from the homologous gorilla (Gogo-B) and chimpanzee (Patr-B) loci. Other unusual features of B*7301 are individually shared with certain alleles of the HLA-A, HLA-C, HLA-F, Gogo-B and Patr-B loci. The B*7301 molecules has sequence elements in common with members of the B7 crossreacting group in the alpha 1 domain and is shown to possess the ME1 epitope, which is held in common with the B7, B22, B27, B42 and B67 antigens. B*7301 has a unique cysteine at position 270 of the alpha 3 domain which appears accessible but probably does not form disulphide-bonded B*7301 dimers in cell membranes. B*7301 represents a newly discovered but ancient lineage of HLA-B alleles that appears poorly represented in the modern human population.
Parham
P
P
Department of Cell Biology, Stanford University, CA.
Arnett
K L
KL
Adams
E J
EJ
Barber
L D
LD
Domena
J D
JD
Stewart
D
D
Hildebrand
W H
WH
Little
A M
AM
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D003545:Cysteine / Q000032:analysis; D004247:DNA / Q000032:analysis / Q000235:genetics; D000939:Epitopes; D015235:HLA-B Antigens / Q000032:analysis / Q000235:genetics* / Q000276:immunology; D006801:Humans; D008969:Molecular Sequence Data; D012699:Serology
D000939:Epitopes; D015235:HLA-B Antigens; C088197:HLA-B73 antigen; D004247:DNA; D003545:Cysteine