Fig 4.

Passive protection in the in vivo rat model. (A) Plot of the number of CFU counted for each infant rat alternatively injected with either preimmune mouse sera or sera from immunized mice, as indicated below the chart. (B) Plot of the number of CFU counted for each infant rat, alternatively injected with either preimmune human sera or sera from human immunized with the 4CMenB vaccine, as indicated. Infant rats were infected with either the NGP165 wild-type or NGP165 NHBA KO strain. Circles indicate single infant rats, while solid horizontal black lines indicate the average of CFU counted for each condition; error bars are also reported. A horizontal dashed line indicates the limit of quantification of the CFU. * = P < 0.05; ** = P < 0.01 (comparing data determined under all described conditions to those determined for rats injected with preimmune sera). No statistical difference between data corresponding to the protection of infant rats from infection by either the NGP165 wild-type or the NHBA KO strain is present. (C) Table showing the results obtained in the in vivo passive protection model.