Investigation of the potential of a 48 kDa protein as a vaccine candidate for infection against nontypable Haemophilus influenzae

This study determined the conservation and protective efficacy of a 48 kDa nontypable Haemophilus influenzae (NTHi) protein (P48). This protein was highly conserved across the strains of NTHi examined and mucosal immunization with recombinant P48 (rP48) significantly reduced the numbers of viable NTHi recovered from the lung following challenge. rP48 induced predominantly an IgG2a antibody response that correlated with the reduction in the number of viable NTHi in the lung. These antibodies were not bactericidal against NTHi. The results suggest that P48 warrants further investigation as a vaccine component for NTHi disease.