MOLECULAR ANALYSIS OF GENES ENCODING OUTER SURFACE PROTEIN-C (OSPC) OF BORRELIA-BURGDORFERI SENSU-LATO - RELATIONSHIP TO OSPA GENOTYPE AND EVIDENCE OF LATERAL GENE EXCHANGE OF OSPC

It has been shown by analysis with monoclonal and polyclonal antibodie s that outer surface protein C (OspC) of Borrelia burgdorferi sensu la te is highly heterogeneous, To determine if the heterogeneity has a ge netic basis, the genes of 18 different B. burgdorferi sensu late strai ns have been amplified by PCR, cloned, and sequenced, The ospC genes c ould be amplified from all strains tested, even from two strains which did not express OspC in detectable amounts. Among the 18 strains, 16 significantly different types of ospC sequences have been found, The s equence identities of the deduced amino acid sequences of different os pC genotypes range between 62 and 80% (determined without the leader p eptide), The sequences correspond to one of the 13 OspC types distingu ishable by analysis with monoclonal antibodies (B. Wilske, S. Jauris-H eipke, R. Lobentanzer, I. Pradel, V. Preac-Mursic, D. Roessler, E. Sou tschek, and R. C. Johnson, J. Clin. Microbiol. 33:103-109, 1995) or re present additional types, Two completely new types were found, and Osp C type 8 (which was found in Borrelia afzelii and Borrelia garinii) co uld be divided into two groups with different sequences but the same a ntibody pattern. Thus, strains belonging to different species or OspA serotypes were always significantly different in their ospC sequences, This was also confirmed by ospA sequence analysis, Interestingly, som e strains of the same OspA serotype or genotype were very heterogeneou s with respect to OspC, while others had nearly identical OspC protein s, Such groups of strains were found among B. burgdorferi sensu strict o, B. afzelii, and B. garinii strains. Cluster analysis of 5'-terminal and 3'-terminal stretches of ospC suggested recent intragenic recombi nation events in the ospC gene of at least one B.afzelii strain, In ad dition, other recombination events between ancestors of strains belong ing to the same or different species were evidenced by this type of an alysis.