Functional differentiation of B lymphocytes in agammaglobulinemia. III. Characterization of spontaneous suppressor cell activity.

The addition of fresh peripheral blood mononuclear cells (PBL) from four of seven patients with agammaglobulinemia to generated hemolytic plaque-forming cells (PFC) resulted in a dose-dependent suppression of PFC. This spontaneous suppressor cell activity (SSA) was restricted to the four patients who could generate a PFC response in vitro. SSA was mediated by a small subset of E-rosetting T lymphocytes characterized by theophylline-sensitive E-receptors and surface receptors for Fc-IgG. The effects of SSA were temperature dependent and reversible, and pokeweed mitogen could prevent the rapid decline of SSA observed during culture. Augmentation of SSA was achieved by agents known to increase intracellular levels of cyclic AMP, whereas lithium chloride abrogated SSA, including the drug-induced effects. Cells mediating SSA may play a role in preventing the normal transition of pre-B cells to B cells in patients with agammaglobulinemia without B lymphocytes.