ROLE OF ARGINASE ON THE PROGRESS OF SCHISTOSOMIASIS CAUSED BY SCHISTOSOMA MANSONI

Schistosomiasis is a parasitic disease caused by trematode flat worms of the genus Schistosoma. Most of the helminthic infections generally associated with the development of T-helper 2 (Th2) cell response. However, the acute stage of the infection induces Th1 response and the chronic stage induces the Th2 response. These Th2 cells produce cytokines that can alternatively activate macrophages and result in production of arginase. Arginase catalyzes the conversion of arginine in to L-ornithine and urea. L-ornithine is a necessary metabolite for the production of polyamines and prolines, which control cell proliferation and collagen production respectively. Parasite antigen-specific host immune respons¬es which are expressed as inflammatory reaction are mostly the cause of host morbidity in Schistosomiasis. Therefore, this review was aimed to describe the role of arginase on the progression of Schistosomiasis. The acute stage of the disease that is characterized by increased Th1 cytokine production, and elevated activity of inducible nitric oxide synthase (NOS) which will result immunopathology are antagonized by the activity of arginase through reduction of cell differentiation and reduced production of nitric oxide by computing to arginine respectively. The immune-suppressive ability of arginase functions as an inhibitor of inflammation and fibrosis following chronic Schistosomiasis. On the other hand schistosomula killing ability of arginase was also suggested. In contrast, inhibition of NOS activity, synthesis of prolines and polyamines favor pathological importance of arginase. Therefore arginase has both inhibitory and pathologic role on the progression of Schistosomiasis. For this purpose, attention should be given on arginase effect study on human Schistosomiasis.