CD4+ T Cells Recognizing PE/PPE Antigens Directly or via Cross Reactivity Are Protective against Pulmonary Mycobacterium tuberculosis Infection
Fig 5
Comparative protective effects of Mtb Δppe25-pe19 or Mtb eccD5 KO strain and induction of ESX-5-related PE/PPE specific T-cell responses by immunization with synthetic peptides.
A) C57BL/6 mice (n = 6 per group), left unvaccinated or immunized s.c. with 1 x 106 CFU/mouse of Mtb Δppe25-pe19 or Mtb eccD5 KO strain, were challenged at 4 weeks p.i. via aerosol route with ≈ 200 CFU/mouse of Mtb H37Rv WT strain. One month post-challenge, the mycobacterial loads were determined in the lungs and spleen of individual mice. NS = not significant, *, **, ***, **** = statistically significant, as determined by One Way ANOVA test with Tukey’s correction for multiple comparisons, p<0.05, p<0.005, p<0.001 or p<0.0001, respectively. B) IL-2, TNF-α and IFN-γ production, detected in the culture supernatants of splenocytes from mice (n = 3 per group), immunized with individual synthetic PE/PPE peptides formulated in CpG(DOTAP) at 10 days p.i. Error bars represent ± SD. The results are representative of two independent experiments.