Immunization with aPseudomonas aeruginosa1244 Pilin Provides O-Antigen-Specific Protection

Abstract

The O antigen is both a major structural outer membrane component and the dominant epitope of most gram-negative bacteria. Pseudomonas aeruginosa 1244 produces a type IV pilus and covalently links an Oantigen repeating unit to each pilin monomer. Here we show that immunization of mice with pure pilin from strain 1244 by use of either the mouse respiratory model or the thermal injury model resulted in protection from challenge with a pilus-null O-antigen-producing 1244 mutant. These results provide evidence that the pilin glycan stimulates a protective response that targets the O antigen, suggesting that this system could be used as the basis for the development of a variety of bioconjugate vaccines protective against gram-negative bacteria.

Glycosylation of Pilin and Nonpilin Protein Constructs byPseudomonas aeruginosa1244

“…We have shown that the P. aeruginosa strain 1244 pilin-bound O-antigen repeating unit is immunogenic (9) and that this structure provides O-antigen-specific protection (29). A T-cell-dependent response against this saccharide is indicated by the strong IgG reaction seen (29). This vaccine target is not limited to the lipopolysaccharide of P. aeruginosa, since the minimal PilO glycan requirement is found in the O-antigen repeating units of many bacterial pathogens (14,28).…”

“…Immunization with either pili (38) or O antigen (15,40,52) from P. aeruginosa has been shown to be protective, as determined in murine models. We have shown that the P. aeruginosa strain 1244 pilin-bound O-antigen repeating unit is immunogenic (9) and that this structure provides O-antigen-specific protection (29). A T-cell-dependent response against this saccharide is indicated by the strong IgG reaction seen (29).…”

“…All animal storage and experimentation took place at the USDA-approved Duquesne University Animal Care Facility. Preparation of strain 683 pili followed a standard methodology (29). A total of 6 female BALB/c mice (Hilltop Lab Animals, Scottdale, PA), approximately 6 to 8 weeks old and weighing 25 g, were immunized using a protocol described previously (29).…”

Genetic engineering ofFrancisella tularensisLVS for use as a novel live vaccine platform againstPseudomonas aeruginosainfections

“…This immunization route was selected because previous studies showed robust mucosal and systemic antibody production in response to alternative Pseudomonas vaccines. 20,21 Serum was collected from mice 42 days post-immunization. Mice that had been immunized with LVS / pGFLI produced robust levels of antibodies specific for P. aerugionsa (P < 0.05) compared to animals treated with PBS (Fig.…”

“…In the more immediate future, studies should investigate whether immunization with F. tularensis / pGFLI protects against a lethal P. aeruginosa infection using the appropriate animal model such as the murine cystic fibrosis model or the burn mouse model. 21,32 …”