STUDIES ON DIPETALONEMA-VITEAE (FILARIOIDEA) .3. ANTIBODY-DEPENDENT CELL-MEDIATED DESTRUCTION OF MICROFILARIAE INVIVO

Abstract

Antibody-dependent cell-mediated destruction of D. viteae microfilariae could be demonstrated in the golden hamster using a micropore chamber technique. Microfilariae were eliminated within 24 h in chambers of 3.0 and 5.0 .mu.m pore size when implanted into amicrofilaremic hamsters (30 wk post-infection). At peak microfilaremia (12 wk post-infection), only some hamsters could efficiently destroy microfilariae. In chambers with 0.3 .mu.m pore size, microfilariae survived for more than 3 wk in all hamsters. In uninfected hamsters, microfilariae could only be eliminated if they were pre-incubated with serum or its 19S fraction containing antibodies to the cuticle of microfilariae. The opsonizing activity of the serum was abolished by 2-mercaptoethanol treatment. The composition of cells adhering to microfilariae was significantly different from the composition of cells which migrated into a chamber. The adhesion patterns on individual microfilariae indicated that no single effector cell type was responsible for the destruction of microfilariae. The eosinophil was the predominant cell type, but neutrophils, lymphocytes and monocytes adhered to the microfilariae. Cellular adhesion led to the immobilization of microfilariae and subsequently to their disintegration within large cell clusters. During the final stages of destruction the contribution of the monocyte became more pronounced.