PROTEINASES SECRETED BY FASCIOLA-HEPATICA DEGRADE EXTRACELLULAR-MATRIX AND BASEMENT-MEMBRANE COMPONENTS

The invasive stages of the parasitic trematode Fasciola hepatica relea se proteinases into the medium in which they are mantained. In this st udy, we investigated the interaction of F. hepatica excretory/secretor y (E/S) products and 2 cysteine proteinases (CL1 and CL2) purified fro m these products with extracellular matrix and basement membrane macro molecules. Fasciola hepatica EIS products contained collagenolytic act ivity on fibrillar types I and III collagen as well as basement membra ne type IV collagen. CLI and CL2 were capable of degrading acid-solubl e type III and type IV collagen but not insoluble type I collagen. In contrast, neither the E/S products nor the purified CLI and CL2 showed elastinolytic activity. Fibronectin and laminin were degraded by E/S products and by CL1 and CL2. Sequence analysis of fibronectin degradat ion products showed that the fragments obtained corresponded to comple te biologically active domains. These results indicate that the cystei ne proteinases secreted by F. hepatica may be involved in the process of tissue invasion by the parasite.