ANIMAL AND HUMAN-ANTIBODIES REACTIVE WITH THE OUTER SURFACE PROTEIN-AAND PROTEIN-B OF BORRELIA-BURGDORFERI ARE BORRELIACIDAL, IN-VITRO, INTHE PRESENCE OF COMPLEMENT

Polyspecific antibodies present in ascitic fluids of mice (pMIAFs) imm unized with whole Borrelia burgdorferi cells exerted borreliacidal act ivity in vitro when tested with complement and homologous antigen but not with heterologous B. hermsii. Similarly, monospecific mouse antibo dies obtained by immunizing mice with purified preparations of outer s urface protein A and B of B. burgdorferi were borreliacidal. On the co ntrary, mouse monospecific antibodies raised against the 41-kDa flagel lar protein of B. burgdorferi did not kill borreliae in the presence o f complement. A complement-mediated, in,vitro, borreliacidal activity was observed in human sera from patients with Lyme disease when antibo dies against OspA and/or OspB were detectable in sera by the Western b lotting technique. The in vitro borreliacidal activity of human sera w as evident after 14 h incubation with live B. burgdorferi spirochaetes and complement, whereas antibodies present in mouse immune ascitic fl uids killed borreliae after 1 h incubation.