Analysis of Leptospira spp., Leptonema illini, and Rickettsia rickettsii for the 39-kilodalton antigen (P39) of Borrelia burgdorferi.

Five serovars of Leptospira interrogans, Leptospira biflexa, Leptonema illini, and Rickettsia rickettsii were examined and found not to contain the 39-kDa antigen (P39) of Borrelia burgdorferi, the Lyme disease spirochete. The specificity of this antigen and its reactivity with human Lyme disease sera should exclude the possibility of false-positive serum samples from patients having had either leptospirosis or Rocky Mountain spotted fever, as well as tick-borne relapsing fever and syphilis, as reported previously (W.J. Simpson, M. E. Schrumpf, and T. G. Schwan, J. Clin. Microbiol. 28:1329-1337, 1990).