Abstract: AimTo clone the gene of staphylococcal enterotoxin C₂ and express it in the form of a soluble fusion protein in E.coli. Then the activation of SEC₂ on mice lymphocyte and its lethal effects on tumor cells were studied. MethodsStaphylococcus aureus SEC₂ gene was cloned into GST gene fusion vector pGEX-4T-1. The resultant plasmid pGEX-4T-SEC₂ was used to transform E.coli BL21, where the GST-SEC₂ fusion protein was expressed efficiently. The rSEC₂ protein was purified with Glutathione Sepharose 4B affinity column and digested with thrombin. The in vitro culture system was utilized to observe the activation of the SEC₂ on mice lymphocyte and the lethal effects on tumor cells of the activated mice lymphocyte. ResultsThe proper gene of SEC₂ was cloned and purified rSEC₂ was obtained. The MTT results indicated that rSEC₂ have strong ability to stimulate mice lymphocyte to proliferate with a dose-dependent manner. With the proliferation of mice splenic lymphocyte, rSEC₂ has a strong lethal effect on tumor cells B16, K562 and K562-AD. ConclusionIn this study, the gene of SEC₂ was cloned and the rSEC₂ protein was obtained, which had strong lethal effect on tumor cells B16, K562 and K562-AD.