Alterations in cell surface phenotype of T- and B-cell chronic lymphocytic leukemia cells following in vitro differentiation by phorbol ester.

The phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) was used for the induction of in vitro differentiation in primary cultures of chronic lymphocytic leukemia cells to study its effects on B-cell antigens [surface IgG, HLA-DR, and the mouse erythrocyte receptor (MR)] and on T-cell antigens [T65 and Lyt-3 (sheep erythrocyte receptor)] found on these cells. Three distinct phenotypes were studied: 1) the common phenotype (slg+, HLA-DR+, MR+, T65+, Lyt-3-); 2) the T-cell phenotype (slg-, HLA-DR-, MR-, T65+, Lyt-3+); and 3) a unique phenotype (slg-, HLA-DR+, MR+, T65+, Lyt-3-). In both the common and unique phenotypes, TPA increased the expression of T65 and HLA-DR, decreased the formation of MR, and induced cytoplasmic immunoglobulin, but it did not induce Lyt-3. In the unique phenotype, TPA also induced surface immunoglobulin. These data suggest that both the common and unique phenotypes are derived from the same lineage, probably B-cell. In the T-cell phenotype, TPA increased the expression of T65 and Lyt-3, but it did not induce any B-cell antigens. These data suggest that the T-cell phenotype is derived from a T-cell lineage distinct from the two B-cell phenotypes.