The ability of vaccination with recombinant OspA from six seroprotective groups of Borrelia burgdorferi sensu lato to induce protection against
infection with homologous and other Lyme spirochetes was examined in hamsters.
Antisera generated against the OspA
proteins of B. burgdorferi sensu stricto S-1-10 and C-1-11 (seroprotective groups 1 and 2, respectively), Borrelia afzelii BV1 (seroprotective group 4), and Borrelia garinii LV4 (seroprotective group 5) were able to kill the homologous spirochete in vitro but not other isolates. Surprisingly,
antisera against B. afzelii PKo (seroprotective group 6) and B. burgdorferi sensu lato LV5 (seroprotective group 3) OspA
proteins were unable to kill the homologous organism, although LV5 OspA
antisera killed the heterologous isolates S-1-10 and LV4. In vivo vaccination studies supported the in vitro findings, confirming that vaccination with a single
OspA protein does not provide complete protection against challenge with all
Lyme disease spirochetes. In addition, OspA
antibodies from some isolates may not protect against the homologous isolate. The induction of protective
antibodies against other B. burgdorferi
proteins may be necessary to insure a comprehensive
Lyme disease vaccine.