Figure 4.
Vδ1 γδ T cells recognized MICA/B on epithelial tumor cell lines and on heterologous and autologous tumor cells. (A and B) Cytotoxicity of the ovary tumor-derived OTδ1 T cell line against HCT116 and Lovo (colon carcinoma cell lines), OV-1063 (ovary carcinoma cell line), and DU145 (prostate carcinoma line) was inhibited by mAb 6D4. Addition of isotype-matched control Ig had no effect (data not shown). The target cell lines expressed MICA/B by staining with mAb 6D4 (ref. 10; data not shown). Similar results were obtained with other tumor-derived Vδ1 γδ T cell lines and additional tumor cell line targets (see text). E:T, effector-to-target cell ratio. (C) MICA/B-induced release of IFN-γ by the OTδ1.1 T cell clone was inhibited in the presence of mAb 6D4 but not of isotype-matched control Ig. Release of IFN-γ (ng/ml) after 48 h of T cell stimulation was quantitated by ELISA (see Materials and Methods). Stimulator cells were C1R-MICA transfectants or tumor cell preparations from breast, lung, or heterologous or autologous ovary carcinomas. Similar results were obtained with another Vδ1 γδ T cell clone derived from a different ovary tumor.