Human lymphoid cell lines and glucocorticoids: II. Whole cell and cytoplasmic binding properties of lymphoblastoid, leukaemia and lymphoma lines.

The glucocorticoid binding properties of 18 human lymphoid cell lines (HLCL) have been investigated. The specificity of steroid binding was confirmed with various glucocorticoid agonists and antagonists. A gradation in whole cell and cytoplasmic glucocorticoid binding capacity was observed in the different cell line types: lymphoblastoid greater than lymphoma greater than leukaemia. The cytoplasmic receptors of leukaemia and lymphoblastoid lines appeared to contain both proteinaceous and phospholipid components. Cytoplasmic steroid-receptor complexes exhibited a wide range of sedimentation coefficients (8.5-11.3S) in low ionic strength buffer but there was no correlation with cell line type or glucocorticoid sensitivity. Activation of these complexes by heat (37 degrees C) or exposure to high ionic strength buffer (0.3 M NaCl) induced nuclear binding of steroid but only complexes in high ionic strength buffer manifested changes in sedimentation coefficient. No correlation was observed between the level or nature of glucocorticoid binding and the cytolethal or cytostatic responsiveness of HLCL to glucocorticoid treatment in vitro. The resistance to cytolethal effects cannot be ascribed to a failure of cells to take up and bind steroid or to significant differences in the molecular species of cytoplasmic receptors present. The molecular mechanisms by which glucocorticoids achieve cytolethal responses in human lymphoid cells has still to be resolved.