Research Article: Synthetic Peptide Vaccine Development: Designing Dual Epitopes into a Single Pilin Peptide Immunogen Generates Antibody Cross‐reactivity between Two Strains of Pseudomonas aeruginosa

Abstract

One of the main challenges of Pseudomonas aeruginosa vaccine development is the design of an antigen that elicits cross-reactive antibodies against multiple virulent strains. Using a rational design approach, we have developed a single 17-residue peptide immunogen that generates antibodies that target the receptor-binding domain of the type IV pilus of more than one strain of P. aeruginosa. Using the receptor-binding domain sequence, of native strain PAO as a template, we have systematically changed up to five residues in the PAO sequence of the peptide immunogen into that of the PAK sequence. We show by indirect and competitive ELISA that the mutant peptide immunogens elicit the development of polyclonal sera that is cross-reactive to both native strain PAO and PAK pilin. We further show that there are at least two separate antibody populations in the polyclonal sera that possess closely related epitopes but which are each strain specific. Moreover, part of the epitope for the PAO-specific antibodies consists of several residues outside the disulfide loop of the receptor-binding domain. This allows us to create two unique epitopes within the same receptor-binding domain sequence.

In silico analysis to identify vaccine candidates common to multiple serotypes of Shigella and evaluation of their immunogenicity

“…A cocktail of all five peptides was found to be more effective than the individual peptide in eliciting both humoral (IgG and IgA) and cellular immune response (TNF- α and IFN-γ). This may be due to the presence of all the predicted B-and T-cell epitopes in the mixture and these results are in concordance with a study by Hackbarth et al in Pseudomonas aeruginosa [ 73 ]. Therefore, these five peptides can be utilized in a multi-epitope vaccine.…”

Peptide-based synthetic vaccines

“…Following this approach, higher antibody titers can be generated against the targeted protein and, more importantly, those antibodies can recognize both pathogen strains used in the design of this epitope. 25 However, while modification of epitopes may be beneficial, longer peptides still need to be processed to activate desired immune responses. 26 Recent research by Melief and co-workers has shown that synthetic long peptides induced stronger T-cell activation than the corresponding protein, and rapid antigen processing in APCs was the key factor which allowed enhanced cellular immune responses.…”

Understanding Pseudomonas aeruginosa–Host Interactions: The Ongoing Quest for an Efficacious Vaccine

“…Synthesis of consensus peptide immunogens that represent the various pilin serotypes to achieve broad protection without the use of a vaccine cocktail has yielded promising results. Cross-reactive polyclonal sera were elicited, generating protective high antibody titres [145,146,[261][262][263]; however, further studies to assess its effectiveness against various clinical strains should be carried out. Proteins of the pilin subcomplexes, such as PilQ, have been investigated.…”