Early cytokine response to lethal challenge of Klebsiella pneumoniae averted the prognosis of pneumonia in FyuA immunized mice.

Klebsiella pneumoniae, a multi drug resistant nosocomial pathogen is associated with pneumonia and immunization gives a hope to fight its infections. A possible vaccine candidate is the conserved protein, yersiniabactin receptor FyuA. Its expression along with the siderophore yersiniabactin increases in bacteria under iron starving conditions prevailing in lungs. In this study, the potential of recombinant FyuA of K. pneumoniae has been evaluated against lung infection in BALB/c mice. Immunization generated both humoral and cell mediated response which conferred protection against the lethal dose of bacteria. Bacterial burden in lungs reduced by 6 log10 CFU/ml after 2nd day post infection as compared to control. Similarly, the levels of pro-inflammatory cytokines IL-17, TNF-α and IL-1β were also reduced significantly; reduced tissue damage was evident from histopathology of lungs in immunized mice. These results indicate the protective role of FyuA which can be a potential vaccine candidate.