Figure 10. Induction of BALT after lethal Mtb challenge correlates with protection from pulmonary granulomatous TB.

(a–c) Co-staining of lung sections with CD3 (green) and CD20 (red) and staining of corresponding sections (d–f) with H&E revealed that (a,d) vaccine-naive animals and (b,e) BCG-vaccinated animals had significantly reduced iBALT follicle formation in comparison with (c,f) MtbΔsigH-vaccinated animals, at necropsy, after lethal Mtb challenge. White and black scale bars, 500 μm. Quantification of multiple lesions in six different animals were used the analysis. (g) Total area (mm²) of iBALT follicles and (h) granulomatous pathology in unvaccinated (red), BCG-vaccinated (light blue) and MtbΔsigH-vaccinated (dark blue) animals. ****P<0.0001 using Student's t-test. Data are means±s.d. At least 10 sections from each slide derived from a lung block from multiple animals in each group were used for statistical analysis (g–h).