CHARACTERIZATION OF THE PROTECTIVE BORRELIACIDAL ANTIBODY-RESPONSE INHUMANS AND HAMSTERS AFTER VACCINATION WITH A BORRELIA-BURGDORFERI OUTER SURFACE PROTEIN-A VACCINE

Significant borreliacidal antibody was induced in volunteers and hamst ers 60 days after primary and secondary vaccination with high concentr ations of recombinant outer surface protein A (rOspA). However, the bo rreliacidal antibody response waned rapidly. Only 1 person had detecta ble cidal activity 180 days after vaccination. Similarly, the borrelia cidal antibody response waned rapidly in hamsters by week 10 of vaccin ation, By contrast, the total anti-rOspA antibody response remained el evated in volunteers and hamsters, When isolates of Borrelia burgdorfe ri sensu late were incubated in sera from vaccinated humans or hamster s, only the vaccine-specific isolate was killed. These results were co nfirmed by challenging rOspA-vaccinated hamsters with different isolat es of B. burgdorferi sensu late. The results showed that monitoring to tal rOspA antibody is inappropriate for evaluating the efficacy of an rOspA vaccine. The rOspA vaccine must be improved to yield comprehensi ve protection and maintain sustained levels of protective borreliacida l antibodies.