WHY DO SOME NEMATODE PARASITES OF ALIMENTARY-TRACT SECRETE ACETYLCHOLINESTERASE

Many gastrointestinal nematodes secrete large amounts of acetylcholine sterases. Antibodies are produced against these secreted acetylcholine sterases and appear to give some protection against infection with som e nematodes. The theory that acetylcholinesterase secreted by gastroin testinal nematodes may act as a biochemical holdfast by reducing contr actions of the alimentary system has not been substantiated; a vasoact ive intestinal polypeptide-like protein is secreted by some species an d may be the biochemical holdfast. Secreted acetylcholinesterases may alter host cell permeability, have an anti-coagulant role, affect glyc ogenesis, and/or be important in certain aspects of acetate and cholin e metabolism. Probably the most important role for acetylcholinesteras e secreted by nematodes is immune modulation and/or reduction of infla mmation in the vicinity of the nematode. The reason why some species o f gastrointestinal nematodes resistant to benzimidazoles contain eleva ted amounts of acetylcholinesterase is unclear. Copyright (C) 1996 Aus tralian Society for Parasitology. Published by Elsevier Science Ltd.