Unusual expression of HLA molecules at the surface of murine cells transfected with HLA-B7 or HLA-A11 genes

The HLA-B7 and HLA-A11 molecules expressed on murine transfectants have been analysed by one- and two-dimensional polyacrylamide gel electrophoresis (PAGE). Two different murine cells, L and P815-HTR have been compared, because it has been previously established that P815 transfectants were much more sensitive to human cytolytic cells than L transfectants. Three kinds of HLA molecules were present on these cells: (1) normal HLA molecules with 2D-PAGE profiles identical to those of the molecules isolated from human cells; (2) HLA molecules of usual size but with more various charges than HLA molecules detected on human cells. This heterogeneity was constantly found with cells expressing HLA-B7 or -A11 antigens, both in L and in P815 transfectants, including several clones. These forms were detected by anti-HLA monoclonal antibodies and by antipeptide (from HLA-B7) antibodies; (3) other unusual products corresponding to shorter heavy chains: molecules of various mol. wts and charges were detected in HLA-B7 but not in HLA-A11 transfectants. They were observed using antipeptide sera but were not seen with anti-HLA monoclonal antibodies. These products were possibly related to the DNA used for transfection and it cannot be excluded that such abnormalities only detectable by antipeptide sera would exist in other transfectants. The functional discrepancies between P815 and L transfectants cannot be clearly explained by these biochemical results.