Figure 2.

MHC class II restriction of responses to mycobacterial antigens by T cells from mc²6030 immunized CD4^–/– mice.(a) MHC class II restriction of responses to mycobacteria-infected BMM. Purified T cells from an mc²6030-primed and boosted CD4^–/– mice were either cultured without APCs, or with BMM from wild-type C57BL/6 or the indicated knockout mouse strains as APCs. Replicate cultures were either left uninfected (open bars) or infected with mc²6030 (MOI 10 : 1) for 2 hr followed by washing to remove uningested bacteria. Supernatant levels of IFN-γ were measured after 5 days of culture. The mouse used for T-cell isolation in this experiment was primed and boosted as in Fig. 1(b), and killed 2 weeks after boosting. Asterisk indicates statistically significant reduction with MHC class II knockout APCs compared to wild-type C57BL/6 APCs (*P < 0·05; one-way anova, Bonferroni post-test).(b) MHC class II restriction of responses to purified M. tuberculosis protein antigens. Purified T cells from a CD4^–/– mouse that was primed and boosted with mc²6030 as in (a) were cultured with BMMs from wild-type or the indicated knockout mouse strains as APCs. The BMMs were pulsed with 10 μg/ml purified antigen 85 A (open bars), antigen 85 complex (filled bars), or no antigen (not shown) for 6 hr before the addition of T cells. IFN-γ levels were determined as in (a); levels were below the limit of detection (∼0·01 ng/ml) for cultures containing T cells purified from naive mice, or in the absence of antigen stimulation.