The expression of MHC antigens on cultured oral keratinocytes and relationship to malignancy.

Major histocompatibility complex (MHC) antigen expression has been postulated to have an important role in host defences against tumour development. In this study the expression of MHC class I and class II antigens in vitro, both constitutive and in response to interferon gamma (IFN gamma), was examined in a series of cell lines established from a rat model of oral carcinogenesis. Constitutive expression of MHC class I and class II antigens was not related to the degree of malignancy of the cell lines, as reflected by their anchorage independence in agarose gels and their capacity to form tumours in athymic mice. MHC class I response to IFN gamma stimulation did not correlate with tumorigenicity, but the MHC class II response was significantly decreased in one of the four tumorigenic cell lines. The results show that the expression of MHC antigens in response to IFN gamma varied between different keratinocyte cell lines but did not consistently reflect the tumorigenic phenotype.