Activation of Leukemic Pro-Suppressor Cells to Become Suppressor-Effector Cells

Abstract

We studied the suppressor activity and surface-membrane antigens of immunoregulatory neoplastic T cells from a child with acute lymphoblastic leukemia and hypogammaglobulinemia. The neoplastic T cells were potent inhibitors of immunoglobulin production by pokeweed-mitogen-stimulated normal B cells when radiosensitive cooperating normal T cells were present. Preculturing trie leukemic cells with normal T cells or soluble factors allowed them to mediate suppression without the need for cooperating T cells. While acquiring new functional capabilities, approximately 95 per cent of the leukemic cells displayed an antigen (OKT-3) that is found on mature normal T cells; 77 per cent displayed an antigen (Tac) that is found on normal activated immunoregulatory effector cells but not on thymocytes or circulating T cells that are precursors of these effector cells. The results suggest that a population of leukemic pro-suppressor cells can be induced to undergo both functional and antigenic differentiation by the influence of normal T cells. (N Engl J Med. 1981; 304: 1382–7.)