A human suppressor lymphocyte subpopulation identified by a heteroantiserum.

A rabbit antiserum has been prepared using peripheral mononuclear cells from a patient with common variable hypogammaglobulinaemia (CVH) who had demonstrable suppressor cells in vitro. This antiserum (anti-Ck), after absorption with pooled normal glass-non-adherent cells and platelets, showed selective reactivity with subpopulations of normal human peripheral lymphocytes. Using indirect immunofluorescence, anti-Ck labelled 36 +/- 8% (mean +/- 1 s.d.) of normal human peripheral lymphocytes. Anti-Ck has the following pattern of reactivity with enriched cell populations: 18% of normal E-rosette-positive cells, 70% of normal E-rosette-negative cells, 60% of lymphocytes from CVH patients, 82% of T gamma lymphocytes, 82% of Con A-activated lymphocytes and 81% of Fc receptor-positive lymphocytes. Anti-Ck reacted neither with glass non-adherent cells (which had been used for absorption), nor with thymocytes, monocytes, granulocytes, membrane immunoglobulin-positive lymphocytes, lymphocytes from patients with chronic lymphocytic leukaemia, or Bristol 7 (B-cell line) cells. The in vitro proliferative response to concanavalin A, phytohaemagglutinin and pokeweed mitogen was significantly enhanced after complement-mediated lysis of normal peripheral lymphocytes using anti-Ck. Immunoglobulin production as measured by a reverse haemolytic plaque assay was also significantly increased by lysis of cell subpopulations with anti-Ck. These studies show that a heteroantiserum can be prepared which identifies antigens common to subsets of human lymphocytes which contain functional suppressor cells.