| Abstract: |
β2-Microglobulin (β2-μ) 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 β2-μ gene (referred to as FO-1C cells) than following transfection with a wild-type human β2-μ 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 β2-μ-free and β2-μ-associated HLA class I heavy chains, the remaining mAb recognize determinants expressed only on β2-μ-associated HLA class I heavy chains. The differential effects of mouse and human β2-μ 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 β2-μ this molecular complex appears to be unstable on the plasma membrane of FO-1 cells. To analyze the interaction of mouse β2-μ 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 02-p 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 β2-μ 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 β2-μ The latter residue is the only one to differ between human and mouse β2-μ in the stretch of amino acids interacting with the α1 and α2 domains of HLA class I heavy chains. The present results indicate that caution should be exercised in the use of HLA class I heavy chains associated with mouse β2-μ to analyze peptide presentation to cytotoxic T cells and of transgenic mice to establish animal models of HLA-linked diseases. © 1993, American Association for Cancer Research. All rights reserved. |
| Keywords: |
controlled study; nonhuman; antigen expression; animal cell; mouse; animal; mice; tumor cells, cultured; transfection; transgenic mouse; monoclonal antibody; antigen presentation; antibodies, monoclonal; immunoglobulin heavy chain; molecular sequence data; antigen specificity; rna, messenger; epitope; cytotoxic t lymphocyte; melanoma cell; melanoma, experimental; base sequence; antibody specificity; immunophenotyping; beta 2 microglobulin; hla a antigen; hla b antigen; hla-a antigens; hla-b antigens; epitopes; antigen antibody reaction; human; priority journal; article; beta 2-microglobulin; support, u.s. gov't, p.h.s.; hla b8 antigen
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