FIG 8.

Correlation of ESAT-6:CFP10-specific IL-17A responses at 8 weeks after M. bovis challenge with lesion severity and mycobacterial burden in the 2007 vaccine efficacy study. Treatment groups included nonvaccinated, BCG-vaccinated, and M. bovis ΔRD1-vaccinated animals. Virulent M. bovis strain 95-1315 was administered by aerosol to all calves 3 months after vaccination, and calves were euthanized 4.5 months after M. bovis challenge (Table 1). Eight weeks after M. bovis challenge, PBMCs (2 × 10⁵ PBMCs/well) were stimulated with 1 μg/ml rESAT-6:CFP10 or medium alone at 39°C for 16 h, and supernatants were harvested for IL-17A analysis by ELISA (bovine IL-17A ELISA VetSet; Kingfisher Biotech). For evaluation of gross pathology, lungs and lymph nodes (mediastinal and tracheobronchial) were evaluated using a semiquantitative scoring system (24). Mycobacterial burdens were determined by culture of a series of dilutions of entire tracheobronchial lymph node homogenates and are presented as CFU per gram of tissue (26). Data (mean ± SEM) are presented as changes in nanograms per milliliter (i.e., antigen stimulation minus medium alone) for each treatment group based on gross pathology scores (A and C) or mycobacterial burdens (B and D). Student's t test P values are provided in the upper left corner of each graph.