Figure 3.

The importance of the polymeric structure of F1 in affording rapid onset of protection against pneumonic plague. (A) Survival curves of C57BL/6 mice (n = 8) vaccinated with polymeric F1 and LcrV (80 µg each/mouse) and with (B) monomeric F1 and LcrV (80 µg each/mouse) 3 days (open squares), 4 days (open diamonds), and 5 days (open circles) before an intranasal challenge with Y. pestis Kim53 (10 LD50). Mortality of control, AlOH-vaccinated animals (n = 4) is shown by a thick dashed line and closed circles. (C) Survival of the mice vaccinated with monoF1, polyF1, or LcrV (80 µg/mouse) 4 days prior to the challenge indicated above. p values calculated by the log-rank test toward control AlOH-vaccinated animals are shown. n.s. = nonsignificant.