FIG 5.
Dampening of IL-17A responses (ELISPOT assay) to M. bovis infection with prior BCG vaccination. Treatment groups included nonvaccinated animals (n = 10) and vaccinated animals (n = 19). The vaccinated group consisted of animals vaccinated with BCG (n = 9) or BCG mutants (i.e., BCG Δfdr8, BCG ΔleuCD Δpks16, BCG ΔmetA, and BCG ΔmmaA4; n = 10). Virulent M. bovis strain 10-7428 was administered by aerosol to all calves 3.5 months after vaccination, and calves were euthanized 4.5 months after M. bovis challenge (Table 1). For IL-17A ELISPOT analysis, PBMCs (2 × 105 PBMCs/well) were stimulated with 10 μg/ml M. bovis PPD (A), 3 μg/ml rAg85A-rTB10.4 (B), or 3 μg/ml rESAT-6:CFP10 (C) for 18 h prior to spot development and counting, as described in Materials and Methods. Results (mean ± SEM) are expressed as spot-forming units (sfu) per 2 × 105 cells for each treatment group at the indicated time points relative to vaccination (Vacc) or challenge. *, response differs from that for nonvaccinated animals at that time point (P < 0.05, as determined by ANOVA followed by Tukey's multiple-comparison test).