Surface antigen expression by a human B-lymphoblastoid cell line treated with 'differentiation' inducers,...

Changes in expression of surface antigens and morphology induced in a human B lymphoblastoid cell line by 'differentiation' inducers DMSO and TPA have been examined. Both of these agents were shown to cause arrest in the G1 phase of the cell cycle, and morphological changes including a decrease in the nuclear to cytoplasmic ratio. In addition, TPA caused a marked increase in membrane area with extensive ruffling. Treatment of cells with 1.25% DMSO for 6 d brought about decreases in the expression of Ia antigens, CALLA, and an immature cell antigen defined by the monoclonal antibody 11D1, and an increase in the expression of surface membrane immunoglobulin. This pattern is consistent with the induction of differentiation towards a more mature B cell. In contrast, treatment of cells with 5 X 10(-8)M TPA for 2 d resulted in increased expression of both Ia and HLA-A, B,C antigens, decreased expression of surface membrane immunoglobulin, and little or no change in the other markers. These changes do not indicate a maturation process and can be explained in part by accumulation of cells in the G1 phase of the cell cycle.