Evaluation of Outer Surface Protein Vaccine Candidates of Borrelia burgdorferi for Lyme Disease

Lyme disease affects several hundred thousand people worldwide annually, yet there is no registered vaccine for the disease available for human use. The disease is caused by Borrelia burgdorferi sensu lato complex bacteria, which harbor numerous outer surface proteins, and many of which have been targeted for vaccine development. However, to effectively combat various Borrelia species, the target protein should ideally be conserved and located in the chromosome. In this study, we evaluated the potential of seven conservative, chromosome-encoded outer surface proteins as vaccine candidates. Unfortunately, four of the initial candidates could not be produced in E. coli. The remaining BB0028, BB0158, and BB0689 proteins were administered to mice in both the free form and as conjugates with virus-like particles (VLPs). In most cases, high antibody titers were obtained, confirming the good immunogenicity of the selected proteins. However, for BB0158 and BB0689 proteins, adverse effects were observed following the injection of free proteins, which were not observed when they were coupled to VLPs. Bactericidity tests of the obtained antibodies suggested that none of the vaccine candidates could induce the production of bactericidal antibodies.