Differential susceptibility to modulation by recombinant immune interferon of HLA-DR and -DQ antigens synthesized by melanoma COLO 38 cells.

Recombinant immune interferon (IFN-gamma) induced a dose-related increase in the synthesis and expression of HLA class II antigens by the cultured melanoma cells COLO 38. Although IFN-gamma-treated melanoma cells COLO 38 continue to express higher levels of HLA-DR antigens than of HLA-DQ antigens, the effect of IFN-gamma was more marked on HLA-DQ antigens than on HLA-DR antigens, as indicated by the dose and incubation time required to induce the changes and by the extent and duration of the increase. The effect of IFN-gamma on HLA class II antigens is significantly higher than that of leukocyte and fibroblast interferons. Analysis by one- and two-dimensional gel electrophoresis of antigens synthesized by melanoma cells COLO 38 in the presence of IFN-gamma did not detect any significant change in the structural profile of the subunits of HLA-DR and -DQ antigens.