Figure 5.

In vivo protection by MAbs and polyclonal antibodies to PNAG against K. pneumoniae KPC infections. (a) C3H/H3N mice (n = 24) were passively immunized with PNAG-specific goat antiserum given intraperitoneally (ip) or intravenously (iv) 24 h and 4 h before intraperitoneal inoculation of K. pneumoniae KPC. Controls received NGS (n = 20) or PBS (n = 7). All sera were either intact or absorbed with K. pneumoniae K2ΔpgaC to remove antibodies to K. pneumoniae other than those to PNAG. The challenge dose was 10⁸ cfu/mouse. P values by unpaired non-parametric t-test comparing NGS to immune serum in mice challenged by the same route. (b) C3H/H3N mice (8/group) were passively immunized with different amounts of the MAb to PNAG (from 25 to 100 μg) or MAb to P. aeruginosa alginate (100 μg) as a control then challenged intravenously with K. pneumoniae KPC (10⁹ cfu/mouse). (c) Mice were injected intraperitoneally with PNAG-specific goat antiserum 24 and 4 h before inoculation with K. pneumoniae KPC. Controls received NGS. P values by log-rank test comparing MAb F598 (100 μg) with MAb F429 (100 μg) (b) or antibodies to PNAG to non-immune serum (c).