Effect of adult T-cell leukemia cells on pokeweed mitogen-induced normal B-cell differentiation

Abstract

Leukemic T cells from Japanese patients with adult T-cell leukemia were studied for their effects on pokeweed mitogen-induced peripheral blood lymphocyte differentiation into immunoglobulin-producing cells. Allogeneic peripheral blood lymphocytes, normal T cells, nonlymphoid leukemia cells, lymphoid leukemia cells other than adult T-cell leukemia cells, and long-term T-cell lines did not suppress normal B-cell differentiation in coculture experiments. Leukemic T cells from three of six patients with adult T-cell leukemia showed a marked suppressive effect. Supernatant fluids obtained from a short-term (48-hr) culture of leukemic T cells from one of these three patients also showed a marked suppressive effect on B-cell differentiation at a final dilution of 1 5 or less when added at the beginning of the culture (on Day 0) or on Day 1. Supernatant fluids, however, did not manifest suppressor activity when added on Day 3 or later, or when heated at 56°C for 30 min before addition.