FIG 7.
Anthrax LT challenge in Ad5-PAopt-immunized rats. Naive Fisher 344 rats or those with PEI were intramuscularly or intranasally vaccinated with Ad5-PAopt or intramuscularly injected with rPA as control. At the indicated time, rats were intravenously challenged with 10 times the LD50 of anthrax lethal toxin and monitored for survival over 48 h. (A) Protective efficacy in naive rats vaccinated intramuscularly with Ad5-PAopt. (B) Protective efficacy of intramuscular Ad5-PAopt vaccination in rats with intranasally induced PEI to Ad. (C) Protective efficiency of intranasal Ad5-PAopt vaccination in rats with intranasally induced PEI to Ad. (D) Dynamic changes of toxin-neutralizing antibodies within 14 days in naive and Ad preinoculated rats. The data are presented as the means ± SEM (n = 6 per group). PEI, preexisting immunity; i.m., intramuscular; i.n., intranasal; i.n.-PEI, intranasally induced PEI; i.m.-PEI, intramuscularly induced PEI.