Interferon gamma regulates HLA-D expression on solid tumors in vivo

In vivo administration of recombinant human interferon-gamma, rIFN-gamma, to nude mice bearing human tumor xenografts resulted in a strong induction of HLA-DR expression on the tumor cells in 2 of 3 lines tested. The induction was dose-dependent and declined rapidly after cessation of therapy. IFN-gamma also switched on DQ and DP products when the xenograft cells were treated in vitro. The in vivo alteration of tumor surface properties by rIFN-gamma may have therapeutic implications.