Effects of dexamethasone on antigen expression and virus production in avian sarcoma virus-transformed cells

We studied the effects of dexamethasone on virus production and antigen expression in avian retrovirus-infected chick embryo fibroblast (CEF) cells. The presence of specific receptors for this hormone in both normal and infected CEF cells could only be demonstrated using cultures that were at or near confluence. Dexamethasone, while not toxic to the cells, exerted a growth-retarding influence when employed at concentrations of 10(-8) or 10(-9) M. These same concentrations of hormone were inhibitory to virus production, elaboration of plasminogen activator activity, and antigen expression as determined in a sensitized lymphocyte stimulation assay. In contrast, infected cells that had been treated with hormone displayed enhanced reactivity in a specific immunofluorescence test.