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.