IgE-dependent adherence and cytotoxicity of rat spleen and peritoneal cells to Litomosoides carinii microfilariae

Serum taken after the termination of microfilaraemia from rats infected with the filarial parasite Litomosoides carinii brought about adherence and cytotoxicity of normal rat spleen and peritoneal cells to microfilariae. The activity could be absorbed to, and eluted from, anti-rat IgE, but not anti-rat IgG, immunoabsorbent columns. Immune serum heated to 56°C for 3 hr did not cause cellular adherence or cytotoxicity; the addition of fresh normal rat serum failed to restore activity. Fresh rat serum did, however, restore activity to immune serum which was inactive after being heated to 56°C for 30 min. EDTA, EGTA and diethylcarbamazine inhibited adherence. It is concluded that IgE antibodies are responsible for cellular adherence and cytotoxicity and that complement may play a part, as yet undefined, in these reactions.