FIG. 2.

(A) Restriction of CD4 T cells by class II MHC (HLA-DR) expression on M. tuberculosis-infected monocytes. Monocytes were pretreated with either L243 (10 μg/ml) or isotypic control MAb (10 μg/ml) on ice for 120 min before the addition of CD4 T cells (2.5 × 10⁴/well) from a long-term T-cell line with and without M. tuberculosis or soluble mycobacterial antigen in a proliferation assay. The results are the means and standard deviations of triplicate wells and are representative of four experiments. (B) Dependence on Vδ2 TCR expression by γδ T cells for activation by M. tuberculosis-infected monocytes. γδ T cells (2.5 × 10⁴/well) were pretreated with either C448.15D (15D) or isotypic control MAb (2 μg/ml) on ice for 60 min before being added to irradiated heterologous monocytes (5 × 10⁴/well) with and without M. tuberculosis (5 × 10⁶/ml) in a proliferation assay. The results are the means and standard deviations of triplicate wells and are representative of three experiments. Ag, antigen; MTB, M. tuberculosis.