Resistance against Brugia malayi microfilariae induced by a monoclonal antibody which promotes killing by macrophages and recognizes surface antigen(s).

Several monoclonal antibodies were produced following the immunization of mice with infective larvae of Brugia malayi. One of these gives a positive fluorescence reaction on the surface of B. malayi microfilariae and this particular monoclonal antibody (IgM isotype) was able to mediate mouse peritoneal macrophage adherence to, and killing of, B. malayi microfilariae in vitro. Adherence and killing were enhanced by fresh normal mouse serum, suggesting a role for complement. When the same monoclonal antibody was passively transferred to mice harbouring microfilariae in their circulation, a complete clearance of microfilariae was observed in 70% of the animals. This monoclonal antibody was able to recognize antigenic determinants (of 110,000 MW) present on the surface of B. malayi microfilariae by radioimmunoprecipitation.