Figure 4 Engineered patient's T cells with anti‐carcinoembryonic antigen (CEA) receptor were specifically activated by autologous tumour cells. Lymphocytes from peripheral blood (PBL) of colorectal cancer patient Nos 1 and 2 were grafted with the anti‐CEA immunoreceptor BW431/26‐scFv‐Fc‐ζ (PBL‐439) (see fig 1B), and 1.25–10×10⁴ grafted cells per well were coincubated with autologous CEA⁺ primary tumour cells (5×10⁴ cells/well) for 48 hours. PBL without BW431/26‐scFv‐Fc‐ζ receptor served as controls. Interferon γ (IFN‐γ) in the culture supernatant was determined by ELISA.