Figure 1
Vaccination with alveolar lining fluid (ALF)-exposed Bacillus Calmette-Guérin (BCG) reduces Mycobacterium tuberculosis (M.tb) bacterial burden in the lung and spleen of C57BL/6J mice and extends survival. (a) Experimental design. (b and c) C57BL/6J mice were vaccinated with NaCl-exposed BCG (NaCl-BCG; gray bars) or ALF-exposed BCG (ALF-BCG; black bars), or left unvaccinated (vehicle control; open bars). Six weeks later, mice were infected with a low-dose aerosol of M.tb. C57BL/6J mice were killed at 14 and 250 days post infection (DPI) and M.tb colony-forming unit (CFU) determined in the lung and spleen. Representative experiment from n=3 with 4–5 mice per group per time-point studied, mean±s.e.m.; one-way analysis of variance (ANOVA) with Tukey’s post hoc test, *P<0.05, **P<0.01, and ***P<0.001; NS: not significant. (d) C57BL/6J mice were vaccinated with vehicle (open circles), NaCl-exposed BCG (gray diamonds), or ALF-exposed BCG (black circles) and challenged with M.tb 6 weeks later. Survival was monitored across a period of 85 weeks. Mice were killed when they met the exclusion criteria documented in animal care and use protocols. Mice in the vehicle group (n=15) displayed a mean survival of 50.00 weeks. NaCl-BCG (n=12)-vaccinated mice had a mean survival of 64.50 weeks. ALF-BCG (n=18)-vaccinated mice had a mean survival of 71.00 weeks. Pooled data from n=3 with 4–6 mice per group (12–18 total mice per group), mean±s.e.m.; log-rank test, *vehicle vs. NaCl-BCG (P=0.0111), ****vehicle vs. ALF-BCG (P<0.0001), and **NaCl-BCG vs. ALF-BCG (P=0.0069). In all the experiments, for each ‘n’ value, ALFs from different donors were used.
