Characterization of Borrelia coriaceae antigens with monoclonal antibodies.

Three monoclonal antibodies (F6F3, F6B11, and F6B3) were developed against Borrelia coriaceae antigens. All three antibodies appeared to be specific for this species and did not cross-react with Borrelia burgdorferi (strains B31 and IRS), Borrelia hermsii, Borrelia anserina, Leptospira interrogans serovar hardjo, or Treponema hyodysenteriae, as determined by indirect fluorescent antibody staining, enzyme-linked immunosorbent assay, and Western immunoblot analysis. Only one of these antibodies, F6B3, bound to spirochetes present in organ smears from the argasid tick, Ornithodoros coriaceus. The antigens recognized by F6F3, F6B11, and F6B3 have apparent molecular weights of ca. 37,000, 35,000, and 16,000, respectively, as determined by Western blot analysis. Antigens were analyzed by immune electron microscopy as well as Western blot and indirect fluorescent antibody staining analysis of spirochetes after enzyme (trypsin and protease K) and detergent (Triton X-100) treatments. These studies suggest that all three antigens are integral membrane proteins. The characteristics of the 37K and 35K proteins are consistent with the outer surface proteins of B. burgdorferi (OSP A and OSP B) described by Barbour et al. (A. G. Barbour, S. L. Tessier, and S. F. Hayes, Infect. Immun. 45:94-100, 1984), while data regarding the 16K protein are less conclusive but may suggest a cytoplasmic membrane location. We suggest that the 37K, 35K, and 16K antigens be designated integral membrane proteins A, B, and C, respectively, as a result of these studies.