title: Immunoregulatory adherent cells in human tuberculosis: radiation-sensitive antigen-specific suppression by monocytes.
abstract: In human tuberculosis, adherent mononuclear cells (AMC) selectively depress in vitro responses to the mycobacterial antigen tuberculin purified protein derivative (PPD). The phenotype of this antigen-specific adherent suppressor cell was characterized by examining the functional activity of adherent cells after selective depletion of sheep erythrocyte-rosetting T cells or OKM1-reactive monocytes. Adherent cell suppression was studied in the [3H]thymidine-incorporation microculture assay by using T cells rigorously depleted of T cells with surface receptors for the Fc portion of IgG (T gamma cells) as antigen-responsive cells. PPD-induced [3H]thymidine incorporation by these non gamma T cells was uniformly reduced (mean, 42% +/- 10% [SD]) when autologous AMC were added to non gamma T cells at a ratio of 1:2. Antigen-specific suppression by AMC was not altered by depletion of sheep erythrocyte-rosetting T cells or treatment with indomethacin. However, AMC treated with OKM1 and complement or gamma irradiation (1,500 rads) no longer suppressed tuberculin responses in vitro. These studies identify the antigen-specific adherent suppressor cell in tuberculosis as an OKM1-reactive, non-erythrocyte-rosetting monocyte. The radiosensitivity of this monocyte immunoregulatory function may facilitate its further definition.
authors.forename: M E
authors.initials: ME
authors.lastname: Kleinhenz
authors.forename: J J
authors.initials: JJ
authors.lastname: Ellner
mesh_terms: D000328:Adult; D005260:Female; D005720:Gamma Rays; D006801:Humans; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology* / Q000528:radiation effects; D010641:Phenotype; D013601:T-Lymphocytes / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000528:radiation effects; D014373:Tuberculin / Q000494:pharmacology; D014397:Tuberculosis, Pulmonary / Q000276:immunology*
chemical_list: D014373:Tuberculin