THE 39-KILODALTON PROTEIN OF BORRELIA-BURGDORFERI - A TARGET FOR BACTERICIDAL HUMAN MONOCLONAL-ANTIBODIES

Three human monoclonal immunoglobulin M antibodies against Borrelia bu rgdorferi, obtained from in vitro-stimulated peripheral blood lymphocy tes, reacted in Western blots (immunoblots) with a prominent 39-kDa pe ptide and a faint band of approximately 66 kDa. Two of these antibodie s showed bactericidal activity without addition of complement. All thr ee antibodies were reactive in an enzyme immunoassay with cloned P39 ( W. J. Simpson, M. E. Schrumpf, and T. G. Schwan, J. Clin. Microbiol. 2 8:1329-1337, 1990), suggesting that the target molecule of these antib odies is identical to the P39 protein. In addition, the majority of su pernatants from human lymphocytes stimulated in vitro with crude B. bu rgdorferi antigen reacted in this assay, demonstrating that P39, altho ugh a minor component of B. burgdorferi is an immunodominant antigen i n these spirochetes. A fourth monoclonal antibody, reacting with OspA, also exhibited bactericidal activity.