An octavalent Lyme disease vaccine induces antibodies that recognize all incorporated OspC type-specific sequences

Lyme disease is the most common vector-borne disease in North America and Europe and, if untreated, has significant arthritic, cardiac, dermatological and neurological sequelae. There is no currently available human Lyme disease vaccine. Outer surface protein C, because of its antigenicity, protective ability, and expression characteristics has emerged as a promising second generation vaccine candidate; however, significant sequence heterogeneity has impeded its development. Analyses of OspC sequences have revealed the existence of stable phylogenetic clusters or types, and that the type-defining sequence variation occurs within defined domains of the protein. Recent data indicating that immunodominant, and potentially protective OspC epitopes are located in these hypervariable regions has allowed development of a tetravalent, epitope-based, chimeric vaccine. In this report, we have extended that previously described tetravalent construct to include four additional OspC types. We demonstrate that the construct is highly immunogenic, and elicits type-specific antibodies that recognize each of the eight incorporated OspC type-specific epitopes. Antibody raised to the octavalent construct readily binds to the surface of strains expressing each component OspC type, indicating that the incorporated epitopes are presented on the surface of intact cells. In addition, the construct elicits antibody isotypes associated with complement-dependent bactericidal activity. These results represent an important step forward in the design of a broadly protective polyvalent OspC-based Lyme disease vaccine.