Figure 3.

Frequency of lipoarabinomannan (LAM)-responsive T cells in healthy donors. (A) Nonadherent peripheral blood mononuclear cells (PBMCs) and CD1⁺ antigen-presenting cells (APCs) from LAM-responsive donors were stimulated with LAM (10 μg/ml) or total lipids, and the frequency of CD3⁺IFN-γ⁺ T cells was determined after overnight incubation by intracellular flow cytometry. The graph shows the individual results of all 12 donors tested. The P value was calculated using the Wilcoxon matched-pairs signed-rank test. The horizontal bars represent the medians. (B) Nonadherent PBMCs and CD1⁺ APCs from LAM-responsive donors were preincubated (1 h) with neutralizing antibodies to antigen-presenting molecules as indicated (10 μg/ml each) before LAM (10 μg/ml) was added. After 18 hours of incubation, the concentration of IFN-γ in the supernatants was measured by ELISA. The figure shows the reduction of IFN-γ⁺ cells as a percentage compared with the samples incubated with LAM in the absence of antibodies. The results are shown as the average ± SEM of three donors. The frequency of LAM-responsive cells in the control cultures was 1.02%. Ab = antibody; MHC = major histocompatibility complex.