CHARACTERIZATION OF AN INHIBITORY SERIC FACTOR FROM TUBERCULOSIS ANERGIC PATIENTS THAT ACTS ON NONADHERENT PPD REACTIVE CELLS

Non-adherent cells from PPD+ tuberculosis patients (TBP PPD+) and from healthy individuals treated with whole tuberculosis anergic immune se ra or with its protein A-Sepharose IgG fraction, or with sera fraction separated by PPD-Sepharose chromatography, were submitted to immunofl uorescence assays. Anti-human IgG or IgM FITC-conjugate were used to r eveal the assays, and results were expressed by a fluorescence percent age or fluorescence index. The presence of IgG over the surface of PPD + non-adherent cells was detected. High fluorescence percentages were observed only in those PPD+ cells treated with whole anergic serum or with its IgG fraction. Positive fluorescence index values were obtaine d only in those PPD+ cells treated with anergic serum, meanwhile fluor escence index was always negative when non-bound fractions from PPD-Se pharose were used. Results suggest that non-adherent population are th e cell targets for the serum inhibitory factor, which previously has b een detected to inhibit antigen response in PPD reactive cells and, po int out the specific behavior of this factor, since it was eliminated by PPD-Sepharose chromatography. The IgG nature of the factor was demo nstrated by SDS-PAGE and immunoelectrophoresis.