Increase in T cells bearing IgG Fc receptors in peripheral blood of patients with tuberculosis by in vitro stimulation with purified protein derivative.

A mixed rosette technique with sheep erythrocytes and chicken erythrocytes coated with heat-aggregated human IgG was used to identify human peripheral blood T lymphocytes bearing IgG Fc receptors (FcR+-T). When peripheral blood lymphocytes from patients with advanced, refractory tuberculosis were stimulated with purified protein derivative (PPD) in vitro, the number of FcR+-T cells increased. No FcR+-T cells developed in peripheral blood lymphocytes from patients with newly diagnosed tuberculosis after stimulation with PPD. The FcR+-T cells from a person who reacted positively to a PPD skin test were isolated by the method of velocity sedimentation. These cells suppressed the PPD-induced proliferative response of autologous peripheral blood lymphocytes as well as the pokeweed mitogen-induced IgG synthesis by B-cells.