Abstract: Objective To investigate the cytotoxic effect of γδ T cells from osteosarcoma patients against interferon-γ
(IFN-γ)-treated osteosarcoma cells in vitro. Methods Human γδ T cells were amplified by zoledronate from peripheral blood
cells of osteosarcoma patients. The expression of Fas on the osteosarcoma cells were measured by flow cytometry and
quantitative real-time PCR analysis before and after IFN-γ treatment. The cytoxicity of γδ T cells against osteosarcoma cells
was evaluated with LDH assay. Results IFN-γ significantly enhanced the susceptibility of the osteosarcoma cell lines HOS and
U2OS to the cycotoxicity of γδ T cells from osteosarcoma patients (P<0.01). IFN-γ obviously up-regulated the expression of Fas
in HOS and U2OS cells (P<0.01). Anti-FasL mAb failed to inhibit the cytotoxicity of γδ T cells in untreated osteosarcoma targets
(P>0.05), but significantly impaired γδ T cell cytotoxicity in IFN-γ pre-treated osteosarcoma targets (P<0.01). Conclusion
IFN-γ can enhance the cytotoxic effect of human γδ T cells from osteosarcoma patients against osteosarcoma cells in vitro.