D3012: Efficacy of reservoir targeted vaccine in eliciting a protective immune response against Lyme Borreliosis in California-endemic reservoir host, Peromyscus maniculatus

Lyme disease  is a potentially life threatening disease caused by spirochete Borrelia burgdorferi and relies on reservoir hosts such as deer mice (Peromyscus leucopus), in eastern United States, and white footed mice (Peromyscus maniculatus), in the western United States,  to complete its sylvatic transmission cycle. The use of an oral reservoir targeted vaccine (RTV), based on the outer surface protein A (OspA) of B. burgdorferi has successfully elicited protective immunity against the B. burgdorferi B31 isolate in Peromyscus leucopus, a primary reservoir of B. burgdorferi in the eastern United States. Although the efficacy of OspA based vaccines to induce protection against B. burgdorferi is well supported, its applicability to reservoir hosts in the eastern United States has not been evaluated. Our study aims to evaluate the efficacy of an OspA based oral bait vaccine in inducing a neutralizing antibody response against a virulent isolate from California (CA4) in a California-endemic reservoir host, Peromyscus maniculatus. Fifteen Peromyscus maniculatus mice were placed on an immunization schedule with RTV for a total of eight weeks. Antibody response was measured in serum collected from vaccinated and control mice using  an Enzyme-Linked Immunosorbent Assay (ELISA). In addition, a pathogen  neutralization assay against two strains of B. burgdorferi (B31 and CA4) was conducted using serum sample collected from mice at the end of the immunization schedule. Performing extensive studies can expand our understanding on the vaccines capabilities and possible targets, aiding in the reduction in Lyme disease related cases, and exposure to B. burgdorferi infected ticks.