Differential effect of human and mouse beta 2-microglobulin on the induction and the antigenic profile of endogenous HLA-A and -B antigens synthesized by beta 2-microglobulin gene-null FO-1 melanoma cells.
beta 2-Microglobulin (beta 2-mu) gene-null human melanoma FO-1 cells display lower reactivity with anti-HLA class I monoclonal antibodies (mAb) following transfection with a wild-type mouse beta 2-mu gene (referred to as FO-1C cells) than following transfection with a wild-type human beta 2-mu gene (referred to as FO-1H cells). Furthermore, binding assays with a panel of anti-HLA class I mAb detected higher reactivity of FO-1C cells with mAb TP25.99 than with mAb CR1-S63, CR10-215, CR11-115, TP67, and W6/32 but similar reactivity of FO-1H cells with all the mAb tested. While mAb TP25.99 recognizes a determinant expressed on beta 2-mu-free and beta 2-mu-associated HLA class I heavy chains, the remaining mAb recognize determinants expressed only on beta 2-mu-associated HLA class I heavy chains. The differential effects of mouse and human beta 2-mu on the reactivity with anti-HLA class I mAb of FO-1 cells reflect more than one mechanism. Besides abnormalities in the processing of HLA class I heavy chains associated with mouse beta 2-mu, this molecular complex appears to be unstable on the plasma membrane of FO-1 cells. To analyze the interaction of mouse beta 2-mu with HLA-A and -B antigens, the HLA phenotype of FO-1 cells was determined, using a combination of isoelectric focusing analysis of antigens immunoprecipitated from radiolabeled cells with mAb to monomorphic determinants of HLA class I antigens, binding assays with a limited number of mAb recognizing HLA class I allospecificities, and sequence-specific oligonucleotide probe typing. Although association with mouse beta 2-mu does not cause marked differences in the expression of HLA-A25 and -B8 antigens on the cell surface of FO-1 cells, it causes a selective reduction in the expression of determinants recognized by anti-HLA-A mAb F4/72 and VF19-LL67 and by anti-HLA class I mAb W6/32 on HLA-A25 allospecificities. The differential effect of the association with mouse beta 2-mu on the antigenic profile of HLA-A25 and -B8 antigens may reflect the different characteristics of the amino acids at residue 12, which interact with residue 33 of beta 2-mu. The latter residue is the only one to differ between human and mouse beta 2-mu in the stretch of amino acids interacting with the alpha 1 and alpha 2 domains of HLA class I heavy chains.(ABSTRACT TRUNCATED AT 400 WORDS)
Wang
Z
Z
Department of Microbiology and Immunology, New York Medical College, Valhalla 10595.
Hu
X Z
XZ
Tatake
R J
RJ
Yang
S Y
SY
Zeff
R A
RA
Ferrone
S
S
D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D000939:Epitopes; D015234:HLA-A Antigens / Q000032:analysis* / Q000276:immunology; D015235:HLA-B Antigens / Q000032:analysis* / Q000276:immunology; D006801:Humans; D008546:Melanoma, Experimental / Q000276:immunology*; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis; D014162:Transfection; D014407:Tumor Cells, Cultured; D001613:beta 2-Microglobulin / Q000235:genetics / Q000502:physiology*
D000911:Antibodies, Monoclonal; D000939:Epitopes; D015234:HLA-A Antigens; D015235:HLA-B Antigens; D012333:RNA, Messenger; D001613:beta 2-Microglobulin