Complement-mediated adherence of cells to microfilariae of Brugia malayi.

Immune sera promote the adherence of human buffy coat cells to microfilariae of Brugia malayi. This effect is augmented by the simultaneous addition of fresh human or guinea pig serum. The heat-labile, adherence-promoting factor present in nonimmune sera appears to be complement. In the absence of antibody, microfilariae activate complement via the alternative pathway and C3 is deposited on the microfilarial sheath.