LYMPHO-PROLIFERATIVE RESPONSES TO VARIOUS FASCIOLA HEPATICA WORM'S ANTIGENS: AN IN VITRO STUDY.

Fascioliasis is an important zoonotic disease with approximately 2-4 million people infected worldwide and a further 180 million at risk of infection. F. hepatica can survive within the bile ducts for many years through its ability to suppress the host immunity with Fasciola cathepsin L1 cysteine protease and Glutathione S transferase playing an important role. The aim of the present study is to investigate the in vitro lympho-proliferative responses of hepatic hilar lymphocytes (HLN) of infected sheep in response to different F. hepatica antigens. The suppressive effects of Fasciola excretory/secretory (ES) and tegument (TEG) and their fractions were also investigated. Our results showed that both ES and TEG had significant suppressive effects on lympho-proliferation, up to 74% and 92%, respectively. When these antigens were fractionated, fraction 3 (MW of >10000-30000) of both ES (64%) and TEG (59%) in addition to fraction 4 (MW of ≤ 10000) of TEG (38%) inherited the suppressive effects. Identification of the potential molecule(s) with such suppressive effects on lymphocytes in TEG fraction 4 could reveal vaccine candidates.