title: Resistance of nematode secretory products to cleavage by mast cell proteinases.
abstract: Mast cell proteinases are known to be released in response to helminth infection, and are, in particular, characteristic of the immune rejection of intestinal nematode parasites. In intestinal mucosal tissue the relevant enzyme is rat mast cell proteinase II (RMCP II) and that of other tissues, including the lung, is rat mast cell proteinase I (RMCP I). The function of these enzymes is unknown, and we have examined the possibility that they directly attack the parasites. This was done by examining the cleavage patterns produced by both proteinases on 125I-labelled excretory/secretory (ES) products of two intestinal nematodes (the infective larva of Ascaris suum, and adult Nippostrongylus brasiliensis) and one which has a pulmonary migration route (the third/fourth stage larva of A. suum). It was first established that all the labelled molecules were proteinaceous, by their susceptibility to broad spectrum proteinases, and that none were host components carried over into culture, by their antigenicity to infected hosts. All the nematode ES products were found to be remarkably resistant to RMCP I and II, only one major component of the infective larva of A. suum being cleaved by both enzymes. This was not found to reflect a resistance to serine proteinases in general, since selected ES components were cleaved by chymotrypsin and trypsin. This would, therefore, argue that, if the enzymes play any direct role in the immune expulsion of nematodes, it is unlikely to be successfully directed at their secretions.
authors.forename: F
authors.initials: F
authors.lastname: Qureshi
authors.forename: M W
authors.initials: MW
authors.lastname: Kennedy
authors.forename: S
authors.initials: S
authors.lastname: Gibson
authors.forename: P Z
authors.initials: PZ
authors.lastname: Ye
authors.forename: H R
authors.initials: HR
authors.lastname: Miller
mesh_terms: D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology; D001200:Ascaris / Q000276:immunology / Q000378:metabolism*; D053818:Chymases; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000378:metabolism*; D009559:Nippostrongylus / Q000276:immunology / Q000378:metabolism*; D011506:Proteins / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D012697:Serine Endopeptidases
chemical_list: D000947:Antigens, Helminth; D011506:Proteins; D010450:Endopeptidases; D012697:Serine Endopeptidases; D053818:Chymases