FASCIOLA-HEPATICA - LOCALIZATION OF GLUTATHIONE-S-TRANSFERASE ISOENZYMES IN ADULT AND JUVENILE LIVER FLUKE

Four cDNA clones (GST-1, -7, -47, and -51) encoding isoenzymes of the detoxification enzyme glutathione S-transferase (GST) have previously been identified and characterised from Fasciola hepatica. In the prese nt study, antisera were generated to synthetic peptides of regions uni que to each of the four GST proteins predicted by the cDNAs. The antis era were characterised, and two were found to distinguish GST-1 from G ST-7, GST-47, and GST-51 as a group. These two antisera were used to l ocalise different GSTs in adult and newly excysted juvenile F. hepatic a. The antiserum to GST-1 was specific and localised GST-1 to the pare nchyma of adult fluke but not to the lamellae of the intestinal caeca. The antiserum to a GST-51 peptide, which cross-reacted with GST-7 and GST-47 but not GST-1, localised the other GSTs not only to the parenc hyma but also to the intestinal lamellae of adult fluke. This appears to be the first evidence of tissue-specific expression of GST isoenzym es in trematodes. In contrast to adult fluke, immunolocalisation of th e GSTs in juvenile F. hepatica revealed the binding of both the GST-1 and GST-51 antisera to the parenchymal cytoplasm, to cytoplasmic exten sions of the parenchyma cells in the subtegumental area, as well as th e excretory ducts. No labeling was observed in the intestinal epitheli um of the juvenile fluke. These results demonstrate that adult F. hepa tica, in contrast to juvenile flukes, contain a GST, which is not GST- 1, associated with the lamellae of the gut and suggest that GSTs in ad ult fluke may play a role in the absorptive function of the adult gut. (C) 1995 Academic Press, lnc.