Long-term cultures of chronic lymphocytic leukemia B cells generate B suppressor cells.

B suppressor cells (Bs) were generated by stimulation with PHA-P or concanavalin A of B cells from peripheral blood of B-cell chronic lymphocytic leukemia (B-CLL) patients. They suppressed well allogeneic mixed lymphocyte reactions. Long-term colonies of B cells from B-CLL were established for up to 6 weeks in liquid media, with B cells acquiring properties of suppressor cells while being cultured. Two types of cultures were observed: cells either grew in compact multicellular colonies or formed diffuse monolayers. Cells that remained alive in cultures for a number of weeks, but did not multiply, did not develop suppressive characteristics. Bs cells retained their phenotypic markers in cultures. Mitosis and lymphoblasts, but no differentiation into plasma cells, were observed. PHA-P-generated Bs were cultured in long-term colonies, retaining their suppressor properties. The establishment of long-term cultures of B-CLL cells may facilitate a better understanding of the nature and characteristics of normal and leukemic B cells.