title: Antigen responsiveness during tuberculosis: regulatory interactions of T cell subpopulations and adherent cells.
abstract: Previous studies from this laboratory demonstrated that adherent mononuclear cells selectively decreased in vitro tuberculin responses in some anergic patients with tuberculosis; subsequently this adherent suppressor cell was characterized as a monocyte. The current study of 41 patients with active pulmonary tuberculosis examined whether T cell subpopulations also acquired antigen-specific suppressor function during Mycobacterium tuberculosis infection, contributed to monocyte-mediated suppression of tuberculin responses, or both. Alteration in the numbers of circulating T-helper (Leu 3a) and T-suppressor (Leu 2a) cells was not observed in patients with tuberculosis, nor did Leu 2a cells selectively modulate in vitro tuberculin responses. The numbers of circulating T gamma cells, a subset of T cells identified by surface receptors for the Fc portion of IgG (Fc gamma R), was increased twofold in patients with active pulmonary tuberculosis. Depletion of T gamma cells from in vitro cell culture consistently and selectively increased tuberculin responsiveness of T cells from patients with tuberculosis. In addition, in the absence of T gamma cells, monocyte-mediated suppression of tuberculin responses was demonstrated in each patient observed. These studies demonstrate that during M. tuberculosis infection T gamma cells acquire antigen-specific suppressor cell activity and suggest that T gamma cells also contribution to immunoregulation modulating the expression of tuberculin-specific suppression by monocytes.
mesh_terms: D000328:Adult; D002448:Cell Adhesion; D000939:Epitopes / Q000276:immunology*; D005260:Female; D006801:Humans; D008212:Lymphocyte Depletion; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D050378:T-Lymphocytes, Regulatory; D014397:Tuberculosis, Pulmonary / Q000276:immunology*
chemical_list: D000939:Epitopes