Localization of leucine aminopeptidase in the Schistosoma mansoni eggs and in liver tissue from infected mice.

Infection with Schistosoma mansoni causes hepatic granuloma formation and fibrosis in response to parasite eggs. The present work localized the leucine aminopeptidase (LAP) in S. mansoni eggs and in liver tissue sections from infected mice. Fresh eggs and livers obtained from infected hamsters were processed and stained with the L-leucine-7-amino-trifluoromethyl-coumarin specific substrate. The L-argnine-7-amino-trifluoro-methylcoumarin and Bestatin (leucine aminopeptidase inhibitor) were used to test the LAP substrate specificity and reactivity. The staining pattern for that enzyme in the egg and liver tissue reflects that the leucine aminopeptidase is a major egg constituent distributed in nearly all the egg except the spine. The control substrates confirmed the substrate broad specificity of LAP. In conclusion, the LAP enzyme is a major egg antigen and the target antigen for the antipathology vaccine development studies.