Molecular mediators and events associated with attenuated MHC class I gene expression.

Numerous examples of altered expression of MHC class I antigens by cells with a malignant phenotype have been described. Of particular interest in this regard has been the description of neoplastic cells with attenuated class I antigen expression. The model system used in this laboratory for understanding the molecular mediators and events associated with attenuation in MHC class I gene expression enlists the use of Abelson virus transformed leukemia cells from which H-2 surface null variants have been immunoselected. For these variants, interdiction in MHC antigen expression occurs at many levels of eukaryotic gene regulation. The regulated expression of H-2 antigens from these somatic cell variants is discussed in relationship to the mechanisms of attenuated MHC class I gene expression described for other leukemias.