Respiratory Immunity is an Important Component of Protection Elicited by Subunit Vaccination Against Pneumonic Plague
ARMY MEDICAL RESEARCH INST OF INFECTIOUS DESEASES FORT DETRICK MD AEROBIOLOGY DIV
Pagination or Media Count:
Mice were vaccinated with a recombinant fusion protein, rF1-V, by an intramuscular prime followed by an intranasal boost, to evaluate protection against pneumonic plague. Forty-two days after the intranasal boost, the mice were challenged by aerosol exposure to Yersinia pestis. Survival after exposure depended upon the dose of rF1-V given i.n. with or 80 survival in the highest dose groups. Pulmonary and serum antibody titers to V were the best predictors of outcome. For vaccinated mice that succumbed to the infection, death was delayed by 1-2 days compared to sham-inoculated controls. Weight loss early after exposure correlated with outcome. Pathology studies indicated a severe, necrotizing bronchopneumonia in vaccinated mice that succumbed to the infection, compatible with a prolonged disease course, while the lungs of sham-inoculated mice had only mild pneumonia, which is compatible with a more rapid disease course. Immunity in the respiratory tract appears to be critical for protection against primary pneumonia caused by Y. pestis.