Figure 6

Direct recognition of STEAP-expressing lung tumor cells by STEAP _281-296 - reactive CD4 T-cell clones. DR15-restricted CD4 T-cell clone SH31 (A) and DR53-restricted CD4 T-cell clones SH6 (B), HK7 (C), and Sa12 (D) were tested for their capacity to recognize antigen directly on STEAP positive LC cells that are either matched or mismatched for the restricting HLA-DR alleles. The HLA-DR-negative Jurkat was also used as negative control. The antigen specificity of these responses was demonstrated by blocking tumor recognition with L243. Columns without bars had SD < 10% the values of the mean. Results are representative of two separate experiments.