A selective effect upon IgG synthesis by Tγ lymphocytes and their products in man

Depletion of T lymphocytes possessing receptors for IgG (Tγ cells) from peripheral blood lymphocytes (PBL) results in enhanced pokeweed mitogen (PWM)-induced IgG synthesis and secretion as compared to IgM. Concanavalin A (Con A) stimulation of Tγ cells causes release of soluble mediators able to suppress immunoblobulin synthesis by PWM-activated PBL. Such factors cause concentration-dependent selective suppression of IgG synthesis. The mediators act upon Tγ cell-depleted lymphocyte populations, also preferentially suppressing the IgG PFC response while leaving the IgM response relatively intact. Thus Tγ cells and their products selectively affect IgG synthesis in vitro.