Hormonal regulation of cell surface expression of the major histocompatibility antigen H-2Ld in transfected cells.

The murine major histocompatibility antigens are cell surface glycoproteins which play an important role in the recognition of foreign antigens by cytotoxic T lymphocytes. Modulation of the level of expression of histocompatibility antigens could therefore be useful for the study of the interaction between the antigen presenting cells and T lymphocytes. The glucocorticoid hormone-inducible promoter, located in the long terminal repeat of mouse mammary tumor virus, was used to replace the promoter region of a cloned H-2Ld class I gene. The chimeric gene was introduced into cultured cells. Glucocorticoid induction of MMTV LTR H-2Ld mRNA could be shown by blot analysis. An S1 nuclease protection assay indicated that the transfected cells accurately initiate the chimeric mRNA. Immunoprecipitation of H-2Ld protein with a specific monoclonal antibody showed inducibility also at the cellular protein level. Fluorescence-activated cell sorter analysis monitored a 3-fold increase of H-2Ld on the cell surface when the transfected cells were grown in the presence of dexamethasone. This increase of H-2Ld expression was accompanied by a corresponding decrease on the cell surface of the endogenous H-2Kk.