Submitted to: Parasitology Today
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 11, 1996
Publication Date: N/A
Interpretive Summary: The extracellular matrix degradation assay has demonstrated the ability of live H. contortus adult parasites to hydrolyze, under physiological conditions, and then ingest, major connective tissue macromolecules. These data support the hypothesis that H. contortus utilizes cysteine protease activity, and not just mechanical activity, to disrupt host tissue. In vivo inactivation of the cysteine proteases of H. contortus might prevent this parasite's access to nutrients, and thus these proteases represent a potential target for control measures.
The significance of cysteine protease activity present in excretory/secretory products of the feeding stages of Haemonchus contortus is discussed. Based, in part, on the in vitro degradation and uptake of extracellular matrix components by live parasites, the authors argue that the cysteine proteases have an essential extracorporeal function in the digestion of host tissues. The merits of the extracellular matrix model, which mimics the in vivo structure of connective tissue and basement membranes, in analyzing host-parasite interactions and, possibly parasite developmental processes, are presented.