Identification of the most immunogenic regions in vaccine candidate P6 (948.7)

Abstract

P6 is a leading protein vaccine candidate for protection against Nontypable Haemophilus influenzae (NTHi) infection. NTHi bacteria are a cause of middle ear infections, sinusitis, pneumonia, and chronic bronchitis. Vaccines that contain only the most immunogenic parts of the protein, often including the antibody binding sites or “epitopes,” can reduce production costs and can sometimes enhance effectiveness. Thus, identifying the most immunogenic part of P6 might be highly attractive to pharmaceutical companies who would like to use P6, or part of P6, in their next vaccine against NTHi. In this study, the P6 epitopes against monoclonal antibodies 4G4 and 7F3 were partially identified. P6 mutant T42R (threonine to arginine at residue 42) was prepared using recombinant DNA technologies, and mutated DNA was transformed into Escherichia coli cells for efficient overexpression. An Enzyme‐Linked Immunosorbent Assay (ELISA) showed decreased binding (compared to wild‐type P6) of the P6 T42R mutant for both the 4G4 and 7F3 antibodies, suggesting that 7F3 and 4G4 interact with residue 42. Nuclear Magnetic Resonance (NMR) spectroscopy was employed to assess structure changes in P6 due to the mutations.Grant Funding Source: This study was supported by NIH NIDCD RO1 08671 (to MEP) and the Rochester Institute of Technology.