apoptosis of human lymphocytes after exposure to hydatid fluid

background: modulation of the immune response is an important strategy by which establish­ment and growth of hydatid cyst in the internal organs of human is warranted. induction of apop­tosis in the lymphocytes might be a considerable component. this study was designed to evaluate apoptotic impact of hydatid fluid (hf) on human lymphocytes. methods: human lymphocytes were treated with hydatid fluid. after 6 hours of exposure, cas­pase-3 activity, the central enzyme of apoptosis cascade, was measured by fluorometric assay in the hf-treated lymphocytes and control cells. in addition, the expression of bax (a pro-apoptotic protein) and bcl-2 (an anti-apoptotic protein) mrna was assessed by rt-pcr after 12 hours of exposure. results: both the ratio of bax/bcl-2 mrna expression and caspase-3 activity were higher in the hf-treated lymphocytes relative to the control group. conclusion: apoptosis could be as a possible mechanism by which echinococcus granulosus overwhelms host defenses.