Recombinant outer membrane protein: a potential candidate for Th17 based vaccine against Klebsiella pneumoniae. (VAC7P.967)

Abstract

Abstract Bacterial pneumonia is a leading cause of mortality and one major pathogen associated with this disease is Klebsiella pneumoniae. Recently, the emergence of antibiotic resistant strains demands an effective vaccine against these bacteria. We have previously shown that intranasal immunization with heat-killed K. pneumoniae or crude outer membrane proteins isolated from K. pneumoniae induced antigen specific Th17 responses and these Th17 cells conferred serotype independent protection against various clinical isolates of K. pneumoniae including the recently described multidrug resistant New Delhi Metallo-beta-lactamase-1 strain. To develop a clinically relevant Klebsiella vaccine, we cloned single OMP genes by PCR from K. pneumoniae and successfully expressed one recombinant outer membrane protein, OmpX, in the BL21 E. coli strain. The purified recombinant OmpX was recognized by Klebsiella immune serum by direct ELISA and also recognized by Th17 cells from Klebsiella immunized mice. In vivo, intranasal immunization of the purified OmpX induced robust mucosal Th17 responses and left IL-17 producing gamma-delta T cells unaffected. Ongoing work will determine whether these Th17 responses will result in serotype independent protection against live bacterial challenge including the multidrug resistant strains.