Inhibition of the cytotoxic activity of MUC1-reactive CTL.M1.1 (A) and CTL.M1.2 (B) by MoAbs. For HLA-A2 blocking experiments, target cells (MZ1774-RCC) were incubated for 30 minutes with 10 μg/mL of MoAbs (BB7.2 (IgG2b) recognizing HLA-A2. For blocking of CD8 molecules or the TCR on the effector cells, CTL were incubated with 15 μg/mL of T8 (IgG1) MoAb recognizing CD8 and anti–Pan-TCR-β BMA 031 MoAb (IgG2b) before adding to the assay. Isotype-matched antibodies (MAM-6, HMFG-1) were used as controls. The assay was performed at E:T ratio of 20:1. The data are shown as the mean and standard deviation from 6 replicate wells.