INDUCTION OF CD8 ANTIGEN AND SUPPRESSOR ACTIVITY BY GLUCOCORTICOIDS IN A CEM HUMAN LEUKEMIC-CELL CLONE

The relationship between glucocorticoid effect and regulation of cell surface antigens was investigated in two models of leukemic cell lines , CEM C7 denoted (r+, ly+) and CEM Cl (r+, ly-). The reactivity of mur ine monoclonal antibodies, anti-CD4-FITC, anti-CD8-FITC, anti-CD2-FITC and anti-calla-FITC, were analyzed using flow cytometry. The suppress or function was determined using [H-3]thymidine incorporation into phy tohemagglutinin-activated peripheral blood lymphocytes. Dexamethasone treatment of a human leukemic cell clone CEM C7 caused an increase in a subset of cells expressing the surface antigen CD8, which is present on suppressor and cytotoxic T-lymphocytes. By comparison, there was n o modification of the expression of CD4 antigen, which is expressed at high levels in these cells. After two days of treatment with 5 x 10(- 8) M dexamethasone, CEM C7 cells showed a two-fold increase in suppres sor activity compared to untreated cells. In contrast, there was no re gulation by glucocorticoids of either the CD8 or CD4 antigens in the l eukemic clone CEM Cl. Furthermore, no modification of the suppressor f unction in CEM Cl cells by dexamethasone was observed. In the human le ukemic cells studied here, the ability to induce CD8 antigen expressio n in a CD4+ cells correlates with the ability to induce cell lysis in a glucocorticoid receptor positive cell population.