SCHISTOSOMA MANSONI - GENERATION OF ANAPHYLATOXIN BY CERCARIAL EXTRACTS

Extracts from Schistosoma mansoni cercariae generate in plasma or serum an activity which contracts the isolated guinea pig ileum. This contraction is inhibited by mepiramine (an anti-histaminic drug). The activity formed by cercarial extracts produces cross-desensitization with the classical anaphylatoxin generated by agar, and induces mast cell degranulation in guinea pig mesentery as well as enhancement of vascular permeability in guinea pig skin. The generation of this anaphylatoxin was blocked by the previous heating of the serum at 56 °C for 30 minutes and by the presence in mixture of 1 × 10-2 M Na33HEDTA. The possible role of this pharmacological active material in the process of skin penetration by cercariae is discussed. © 1969.