IgG and IgA responses to whole cell 23F or 6B pneumococci following 23F or 6B challenge, respectively.

ELISAs were performed using 23F or 6B pneumococci as targets to measure specific IgG (A, C and E) and IgA (B, D and F) titers in serum (A and B), NW (C and D) and BAL (E and F). Values shown are the mean antibody titers (of triplicates), pre and post 23F (n = 7) or 6B (n = 8) challenge (x-axis). *represents statistical significance between pre- and post-inoculation antibody titers.