SS40 - THE ZINC ENDOPEPTIDASE SECRETED BY INFECTIVE LARVAE OF STRONGLOIDES STERCORALIS

Infective larvae of a pathogenic nematode of humans, Strongyloides ste rcoralis, release a potent zinc endopeptidase activity which has a bro ad substrate specificity for constituents of extracellular dermal matr ix, including elastin. Specific inhibitors of zinc endopeptidases prev ent the penetration of mammalian skin by S. stercoralis larvae. We now report the molecular size and isoelectric point of the S. stercoralis zinc endopeptidase at 40 kDa, pI 5 by zymogram analysis. The activity was not influenced by incubation with P-mercaptoethanol at 22 degrees C, but was inactivated by incubation at 100 degrees C for 2 min. The enzyme, which we term Ss40, is immunogenic and stimulates humoral IgG antibodies during infection of humans; the activity was immunoprecipit able from ES with pooled infection sera. In addition, a HPLC-enricbed Ss40 preparation stimulated the release of histamine from peripheral b lood leukocytes of S. stercoralis-infected persons, suggesting that Ss 40 is allergenic in humans. (C) 1995 Academic Press, Inc.