(C) Survival of mice (n=10) upon intranasal infection with 2x106 CFU of S. pneumoniae T4 together with peptide P2 or CP2 or P2-NPs over 3 days post infection. Infected mice were checked twice daily in the morning at 9 am (early check) and in evening at 7 pm (late check) for clinical symptoms. Unloaded NPs and the isogenic PLY mutant strain (T4Δply) served as negative controls. * denotes P < 0.05 and ** denotes P < 0.005 by Mantel Cox test. Exact P values are shown in Appendix Table S4. 