ObjectiveTo detect the expression of CD1d in various tumor cell lines, and to explore the sensitivity of iNKT cells in killing different tumor cell lines.MethodsA variety of tumor cell lines were prepared into single cell suspensions, the tumor cells were incubated with CD1d antibody, and the expression of CDld in various tumor cell lines was detected by flow cytometry. The iNKT cell and tumor cells were co-incubated according to the effect-target ratio of E:T=10:1, 5:1 and 1:1. The killing effect of iNKT cells on tumor cells was monitored by RTCA esight imaging, the expression of molecules on the surface of iNKT cells was detected by flow cytometry, and the cytokine secretion after activation of iNKT cells was detected by ELISA.ResultsThe CD1d expression was detected in Jurkat, Jeko-1, U2OS, A375 and Hep-3B cell lines, and the positive rates was 98.40%, 93.80%, 67.10%, 43.80% and 11.00%, respectively. While tumor cell lines Huh7, OVCAR3, MKN45, AGS, H460, MKN7 and MDA-MB-453 were CD1d negative. Activated iNKT cells expressed NK cell activation receptors CD226 and NKG2D, and at the same time, they could rapidly secrete large amounts of cytokines and cytotoxic molecules such as IFNγ and Granzyme B.ConclusionThe iNKT cell has extensive killing ability against CD1d positive (except Jeko-1 cells) and negative tumor cell lines, and the killing effect is the strongest when target ratio is high. α-Galcer can enhance the killing ability of iNKT cells on CD1d positive tumor cell lines.