Antibodies to OspB prevent infection of C3H mice challenged with Borrelia burgdorferi isolates expressing truncated OspB antigens.

Truncation of outer surface protein B (OspB) of the Lyme disease agent, Borrelia burgdorferi, may allow the organism to escape immunological destruction and render an OspB-based vaccine ineffective. To investigate this possibility, we have identified two isolates, 297 and CA4, which predominantly express a truncated form of the OspB antigen. In each case, nucleic acid sequencing revealed that truncation of the OspB antigen resulted from a nonsense mutation within the 3', end of the ospB gene. Growth inhibition and protection studies demonstrated that both isolates were neutralized by an anti-OspB serum. Our results indicate that truncated forms of the OspB antigen possess epitopes that may represent important targets for neutralizing antibodies and thus, support the inclusion of OspB as a component of a subunit vaccine.