Abstract

The outer membrane protein F(OprF) of Pseudomonas aeruginosa is known to be conserved among various P. aeruginosa strains, and has been shown to be protective against P. aeruginosa infections in animal model systems. In order to identify epitopes essential for immunogenicity and protective efficacy, we synthesized 14 peptides of the mature OprF protein and evaluated their immunofenicity in mice. Among them two peptides in the carboxy-terminus region of OprF, peptide 3(^204GAPAVAEVVRVQLDVKFD^221) and peptide 14(^305NATAEGRAINRRVE^318), elicited high titer of antibody responses in mices, and reacted strongly with anti-OprF antibodies. The peptides were also examined for reactivity with antisera from human volunteers immunized with a P. aeruginosa vaccine composed of outer membrane proteins and from patients who recovered from Pseudomons infections. Peptide 3 showed high reactivity with both antisera from the vaccines and the convalescents, comparable to that of peptide 14, which has been previously reported to afford protection against P. aeruginosa in a murine acute infection model. Substitution of three amino acids KFD in peptide 3 with AAA significantly diminished its reactivity to the antisera, indicating that the core sequence ^216LDVKFD^221 is crucial for its immunogenicity and reactivity with human antisera. These data suggest a potential use of this peptide for development of a vaccine against P. aeruginosa infection.

• Keywords: Convalescence sera; Immunodominant epitope; OprF; P. aeruginosa