The escalating spread and density of tick populations underscore the urgent need for enhanced surveillance and risk assessment strategies for tick-borne diseases (TBD). Biomarkers derived from the antibody response to tick saliva can be used to facilitate the surveillance of vector establishment in novel regions, assess anti-vector interventions and diagnose TBD through documentation of antecedent tick bites in suspected cases. Here, we derived short peptides from previously identified immunogenic proteins—namely IrCRT, IrSPI, and IrLIP—through bioinformatic predictive analysis using the Immune Epitope Database. ELISAs performed with experimentally controlled sheep sera infested with Ixodes ricinus were used to assess the level of antibody response of IgM and IgG to the peptides derived from these three proteins. Next, we tested the candidates on sera derived from both field and clinical isolates of tick-exposed individuals. For all sera, we obtained different IgM and IgG responses with varying degrees of immunogenicity detected per peptide. Further, through use of an exploratory microarray assay (PepperPrint™), we selected new peptides based on their ability to be recognized using serum from experimentally infested sheep. Amongst the top randomly generated peptides, we found a more specific immunogenic response against the IgG antibodies when compared to IgM.  Selected candidates were further tested against experimentally-controlled infested sheep sera, as well as field and clinical isolates. Finally, candidates were cross-validated against mosquito-exposed sera to ensure vector specificity. This study offers the potential for developing new effective strategies for the surveillance and diagnosis of tick-related risks as well as the control and prevention of TBD.

Paris Post-docs seminar series.