FIGURE 4.

TCR-Ts do not recognize and kill ENPP1 + tumor cells. (A) Western Blot analysis showed ENPP1 expression in different cell lines. MB231-Luc was derived from MDA231 by transfecting Luciferase gene. (B) Flow cytometry data demonstrated the HLA-A2 expression level on the surface of different cell lines by anti-HLA-A2 antibody staining. The hatched lines indicate the isotype staining controls. (C) ELISA assay showed the level of IFNγ production by TCR-Ts after stimulation with indicated cell lines in the presence of 1 μg/ml ENPP1 peptide. (D,E). The activation of TCR-Ts by different cell lines in the absence of ENPP1 peptides was presented. Only the TCR3-Ts were weakly activated, while TCR1-Ts and TCR2-Ts could not be activated by ENPP1 + MB231 and MCF7 cells. (F) LDH assay showed that TCR-Ts do not kill the ENPP1 + MB231 cells. HepG2 cells were used as positive control. Student t-test was used for statistical analysis. This experiment was repeated 4 times with similar data.