Protective Efficacy of a Borrelia burghdorferi BB0172 Derived-Peptide Based Vaccine Formulation in the Murine Model Against Lyme Disease

Lyme disease (LD) is the most prevalent tick-borne disease in the US. The disease in humans is characterized by the development of a characteristic skin rash (erythema migrans), arthritis, cardiac and neurological signs. Vaccination is the most efficient preventive measure that could be taken to reduce the incidence of the LD around the globe; however at present no vaccine is available for human use. To date, extensive research has been devoted to develop a protective vaccine for use in humans. Nonetheless, it is challenging to find a conserved antigen to combat the heterogeneity within the Lyme spirochetes. Also, the complex biology of Borrelia species and alterations in the expression of outer surface membranes, put another burden to generate effective LD vaccines. In this work, PepB, a BB0172-derived peptide was evaluated in scaffolded and conjugated formulations as a vaccine candidate in murine model of LD. Overall, we observed that, when animals are immunized with pepB conjugated to the tetanus toxoid, they develop high antibody titers that induce protection when animals are infected by needle inoculation. Furthermore, sera from immunized individuals showed bactericidal properties. Finally, the peptide conjugations tested did not protect against the tick infection by clearing infection, but a significant reduction in bacterial burden was observed in immunized groups compared to control groups. Therefore, we conclude that PepB conjugated antigens can serve as an alternative to prevent Lyme disease; nevertheless further studies will be needed to evaluate further delivery methods as well as antigen presentations (polyvalent vaccines, microencapsulation, etc.)