FIG 2.

Anti-FHbp passive protective activity against bacteremia. Human FH transgenic infant rats were treated i.p. with sera from immunized mice and 2 h later challenged i.p. with 3,000 or 4,000 CFU of group B strain R1 or S1. Blood cultures were obtained 12 h after the bacterial challenge. Each symbol represents result of an individual animal. (A and D) Sera diluted 1:10 from negative-control mice immunized with aluminum hydroxide; (B and C) sera diluted 1:40 or 1:160, respectively, from mice immunized with FHbp ID 1 (antigenic variant in 4CMenB vaccine); (E and F) sera diluted 1:40 or 1:160, respectively, from mice immunized with FHbp ID 4 (matched the FHbp variant in the R1 and S1 isolates). Not shown are data from control animals treated with 10 μg of an anticapsular MAb, which resulted in sterile blood cultures. Panels with asterisks were statistically significant (panel B, P = 0.0239; panel C, P = 0.0032; panel F, P = 0.0146).