Polymorphisms of major surface proteins of Borrelia burgdorferi.

Forty-five isolates of Borrelia burgdorferi, the etiologic agent of Lyme disease, were examined with monoclonal antibodies directed against the surface proteins, OspA and OspB. Eighteen of 21 strains of European origin could be distinguished from 24 North American strains on the basis of their reactivities with two antibodies, one specific for an OspA protein and one specific for an OspB protein. Differences in antibody reactivities were associated with differences in the electrophoretic migrations of OspA and OspB proteins. Thus, Lyme disease borreliae are polymorphic with respect to their major surface proteins. The demonstrated distinctions between the majorities of European and North American strains may have relevance for both epidemiologic and pathogenic studies of Lyme disease.