USE OF RECEPTOR ANTIBODIES TO DEMONSTRATE MEMBRANE GLUCOCORTICOID RECEPTOR IN CELLS FROM HUMAN LEUKEMIC PATIENTS

Anti-peptide antibody to the human glucocorticoid receptor (GR) was pr oduced and used to demonstrate that a subset of the GR population resi des in the plasma membrane of human leukemic cells. Characterization o f the antibody with intracellular GR (iGR) showed its ability to shift [H-3]triamcinolone acetonide-labeled GR (4S protein) from two human l eukemic cell lines to a higher density in sucrose gradients; Western a nd autoradiographic analysis of affinity-labeled ([H-3]dexamethasone 2 1-mesylate) receptor revealed an immunoreactive and competitively labe led band of 94 kDa. CCRF-CEM cell membrane GR (mGR) resolved as a >7S protein on density gradients and immunoselected cell surface protein l abeled by whole cell biotinylation or affinity-labeling with [H-3]dexa methasone 21-mesylate was approximately 145 kDa, demonstrating that mG R was larger in size than iGR, as has been shown previously for the mG R of mouse lymphoma cells. Analysis of mGR in lymphocytes of leukemic patients and the CCRF-CEM cell line indicated differences in levels of expression as shown by FACS and immunocytochemical analyses. We are c urrently using this system to study the correlation between the quanti ty of membrane-resident GRs and the glucocorticoid-induced lytic respo nse, a relationship previously shown in the murine (S-49 cell) system.