Control of B-lymphocyte function. I. Inactivation of mitogenesis by interactions with surface immunoglobulin and Fc-receptor molecules.

Abstract

Mouse spleen cells were incubated with [rabbit or goat] anti-Ig [immunoglobulin] antibodies for 1 h, washed, exposed to LPS [Escherichia coli lipopolysaccharide] for 1 h, washed, and their DNA synthetic responses assayed 2 days later. The 1 h incubation with anti-Ig antibodies produced a profound, internal, and long lasting state of inactivation in the B [bone marrow-derived] cells. Experiments with anti-Ig fragments and other ligands showed that the inactivation occurred optimally when surface Ig molecules and Fc receptors were bound simultaneously. The role of the classical capping and clearing cycle was also investigated. Capping and clearing were not necessary sufficient for the inactivation to occur, and the signals, but only secondarily the ligands themselves were transmitted across the membrane. Capping and clearing were viewed as a natural regulatory mechanism by which the B cell attempts to clear its membrane of perturbations and signals from the exterior.