POLYMORPHISM IN OSPC GENE OF BORRELIA-BURGDORFERI AND IMMUNOREACTIVITY OF OSPC PROTEIN - IMPLICATIONS FOR TAXONOMY AND FOR USE OF OSPC PROTEIN AS A DIAGNOSTIC ANTIGEN

The nucleotide sequences of the ospC gene from five Danish human Borre lia burgdorferi isolates representing all three B. burgdorferi genospe cies (B. burgdorferi sensu stricto, Borrelia garinii sp. nov., and gro up VS461) and from the American type strain B31 were determined and co mpared with the published ospC sequence from the German B. burgdorferi isolate PKo (R. Fuchs, S. Jauris, F. Lottspeich, V. Preac-Mursic, B. Wilske, and E. Soutschek, Mol. Microbiol. 6:503-509, 1992). The ospC g ene was present in all isolates, regardless of the presence or absence of its product, OspC. The deduced amino acid sequences of OspC from t he seven isolates were aligned and revealed pairwise sequence identiti es ranging from 60.5 to 100%. Differences were scattered throughout th e amino acid sequences. A phylogenetic tree was constructed and reveal ed three distinct phenotypic groups OspCI to OspCIII corresponding to the three delineated genospecies. Immunoblot analysis revealed that th e seven OspC proteins tested have both common and specific epitopes. T here is significant epitope diversity, since even polyclonal antisera showed serotype-restricted specificity. Therefore, a serodiagnostic as say for Lyme borreliosis utilizing OspC as a test antigen should inclu de all three OspC phenotypes in order to obtain a species-wide sensiti vity.