FIG 6.
Specificity and cytokine profile of ribosome-specific CD4+ T cell responses. C57BL/6 mice were immunized i.v. with 5 × 107 CFU of IKEPLUS or BCG-Danish. Two weeks later, CD4+ T cells were purified from splenocytes and tested by an ELISPOT assay for the production of IFN-γ or IL-4, as well as IL-17A (not shown), in response to ex vivo stimulation with the indicated antigens (the rplJTB146–160 peptide [10 μg/ml], the ribosome-enriched fraction from IKEPLUS [5 nM], purified E. coli ribosomes [5 nM], the M. tuberculosis sonicate [10 μg/ml], the TB9.8 peptide [10 μg/ml], or the IKEPLUS sonicate [10 μg/ml]). Responses that were significantly different between IKEPLUS- and BCG-immunized animals are indicated. *, P < 0.05; **, P < 0.01; ***, P < 0.0001; ns, not significant (as determined by ANOVA). Positive-control wells stimulated with concanavalin A (5 μg/ml) demonstrated the ability of the assays to detect all three cytokines (not shown). Symbols represent cells harvested from individual mice (n = 6), and data shown are combined data from two independent experiments.