Enhancement of the protective efficacy of an oprF DNA vaccine against Pseudomonas aeruginosa

Abstract

The outer membrane protein F gene (oprF) of Pseudomonas aeruginosa was recently shown by us to protect mice from P. aeruginosa chronic pulmonary infection when used as a DNA vaccine administered by three biolistic (gene gun) intradermal inoculations given at 2-week intervals. In the present study, we used two different strategies to improve the protective efficacy of the DNA vaccine. In the first strategy, mice were primed with two biolistic intradermal inoculations with the oprF vaccine and then were given a final intramuscular booster immunization containing either a synthetic peptide-keyhole limpet hemocyanin (KLH) conjugate or a chimeric influenza virus. Both the synthetic peptide conjugate and the chimeric virus contained peptide 10, a previously identified immunoprotective epitope of protein F. The second strategy involved the addition of a second outer membrane protein to the vaccine. DNA encoding a fusion protein comprised of the C-terminal half of protein F fused to OprI was administered by three biolistic intradermal inoculations. Challenge with P. aeruginosa in a chronic pulmonary infection model demonstrated that boosting with the chimeric virus (but not with peptide-KLH) or adding oprI to the DNA vaccine significantly enhanced protection as compared to that afforded by the oprF vaccine given alone. Thus, both strategies appear to augment the protection afforded by an oprF-only DNA vaccine.

Blocking of the TLR5 Activation Domain Hampers Protective Potential of Flagellin DNA Vaccine

“…Specificity of serum IgG was analyzed by using immunoblots of flagella prepared from PAO1 and PAK as described previously (29,33). After separation by SDS-PAGE, samples were blotted on polyvinylidene difluoride membranes.…”

Protection against P. aeruginosa with an adenovirus vector containing an OprF epitope in the capsid

“…Immunization with recombinant OprF has been shown to generate protective immune responses, and recombinant OprF is being tested as a vaccine candidate against infections with P. aeruginosa in animals and humans (22)(23)(24)(25)(26)(27)(28). Genetic immunization with DNA encoding an OprF/OprI hybrid via a gene gun in mice resulted in humoral immunity against P. aeruginosa (29). Various immunogenic peptides have been identified in the outer loops of OprF, among them the B cell epitopes TDAYNQKLSERRAN (peptide 9, identical to Epi6) and NATAE-GRAINRRVE (peptide 10, identical to Epi8) (21).…”

“…OprF has been shown to be immunogenic in laboratory animals and humans, and the sequence of OprF suggests that there are several extracellular loops that serve as good B cell epitopes ( Figure 1) (21)(22)(23)(24)(25)(26)(27)(28)(29). The Ad hexon is the most abundant immunogenic of the Ad capsid proteins (30)(31)(32)(33).…”

Recent developments for Pseudomonas vaccines

“…125,126 Many of the initial vaccination studies demonstrated that immunization with either OprF or OprI as immunogens elicits cross-reactive, opsonizing and protective antibodies in animal models or humans. [127][128][129][130][131][132][133][134] To enhance synergistic immunogenicity, a recombinant hybrid vaccine using immunogenic epitopes from OprF and OprI was developed. Active or passive immunization with this OprF-OprI vaccine was protective against systemic P. aeruginosa infection in various animal models.…”

“…151 OprI was demonstrated to adhere to the mucosal surfaces of the respiratory and intestinal tract and may so act as a mucosal carrier to facilitate antigen delivery to antigenpresenting cells. 152 In addition to conventionally extracted or recombinant protein preparations, Opr have been successfully tested in several other formulations including DNA vaccines, 129,130 peptide vaccine, 153 viral vectors, 154-159 dendritic cell-pulsed, 160 or heterologously expressed in bacterial vectors. 70 Furthermore, many of the chimeric vaccines include OprF/OprI as their critical component.…”