Abstract: Objective To investigate the effect of IFN-α1b on cytotoxic activity of human γδT cells against Daudi cells. Methods Daudi cells treated with IFN-α1b were functioned as target cells and γδT cells treated with IFN-α1b as effector cells. The cytotoxic activity of γδT cells was tested by a lactate dehydrogenase release assay. ELISA kits were applied to detect the level of granzymes B and IFN-γ released from γδT cells. Flow cytometry was performed for examining Fas receptor, stress protein ligands on Daudi cells and activation markers CD69 and CD25 of γδT cells. Results Both IFN-α1b pretreated Daudi cells or γδT cells significantly augmented the cytotoxic activity of γδT cells against Daudi cells (P＜0.0001). IFN-α1b also enhanced granzymes B and IFN-γ secretion of γδT cells(P＜0.05); IFN-α1b significantly up-regulated the expression of Fas receptor and stress ligand ULBP4 on but not ULBP3 on Daudi cells; IFN-α1b also increased the expression of CD69 but not CD25 on γδT cells. Conclusions IFN-α1b improves cytotoxicity of human γδT cells against cancer cell line Daudi by different mechanisms.So it is believed that IFN-α1b plus γδT cells may enhance the anti-tumor effect of γδT cells.

Key words: IFN-α1b, γδT cells, Daudi cells, cytotoxicity