Fig. 2.

Enhancement of TNF-α release in the presence of a panel of plasma from patients with active pulmonary tuberculosis and healthy PPD skin test donors. Purified adherent cells (1 × 10⁶ cells in 500 μl) were stimulated with PPD at 10 μg/ml. TNF-α release was assessed in antigen stimulated adherent cells in the presence of either control plasma, or plasma from patients with active pulmonary tuberculosis. All plasma samples were heat inactivated and added at a dilution of 1:500. Spontaneous release of TNF-α by adherent cells was also assessed in the presence of plasma samples without any added stimulant, and was <10 pg/ml for all plasma samples tested. □, Control plasma; , patient plasma.