Class I-induced resistance to natural killing: identification of nonpermissive residues in HLA-A2.
Structural characteristics of major histocompatibility complex class I antigens associated with natural killer (NK)-resistance phenomena were examined. Previous research has shown that transfection of class I genomic DNA clones into class I-deficient, NK-sensitive target cell lines results in transfectants exhibiting class I+, NK-resistant phenotypes. In contrast to the HLA-A3, -B7, -B27, and -Bw58 class I molecules, the HLA-A2 class I molecules were shown not to protect target cells from NK activity. Here we show that this nonprotective phenotype maps to the alpha 1 domain of the HLA-A2 molecule by examining the NK-protective capacity of the natural interdomain recombinant HLA-Aw69 molecule. HLA-Aw69, which consists of an alpha 1 domain exhibiting homology with HLA-Aw68, and alpha 2/alpha 3/transmembrane-cytoplasmic domains, exhibiting homologies with HLA-A2, mimics HLA-Aw68 and provides HLA-A,B null target cell (C1R) transfectants with increased resistance to NK. Further, the inability of transfected HLA-A2 to confer protection against NK activity can be completely attributed to the expression of a "nonpermissive" residue at position 74 in the alpha 1 domain. Site-directed mutation of the His-74 residue in HLA-A2 to the Asp-74 (HLA-A3, -Aw68, -Aw69, -B7) residue generates a mutant that provides C1R cell line transfectants an NK-resistant phenotype. As His-74 blocks access to a side pocket in the HLA-A2 antigen-binding cleft, these results support the critical involvement of residues within the peptide-binding groove of class I molecules in determining the NK susceptibility phenotype of class I+ target cells.
Storkus
W J
WJ
Department of Microbiology, Duke University Medical Center, Durham, NC 27710.
Salter
R D
RD
Alexander
J
J
Ward
F E
FE
Ruiz
R E
RE
Cresswell
P
P
Dawson
J R
JR
D000483:Alleles; D000911:Antibodies, Monoclonal; D002460:Cell Line; D003001:Cloning, Molecular; D003602:Cytotoxicity, Immunologic; D005455:Fluorescent Antibody Technique; D015789:HLA-A2 Antigen / Q000235:genetics / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000276:immunology*; D006650:Histocompatibility Testing; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D008297:Male; D016297:Mutagenesis, Site-Directed; D010641:Phenotype; D010957:Plasmids; D011863:Radioimmunoassay; D014162:Transfection
D000911:Antibodies, Monoclonal; D015789:HLA-A2 Antigen; D015395:Histocompatibility Antigens Class I