Figure 5

(a) 3G4 and 3G8 cells were incubated with PIPLC supernatants from CEACAM5 transfectants, vector control 293 T cells, or (b) IECs cell line T84. FO-1 cells were used as negative control. Absorbed or unabsorbed supernatants were subjected for immunoblotting using Col-1 or B9 mAbs. 3G8 but not 3G4 were capable of absorbing CEACAM5. Data are representative of three independent experiments. (c) 3G cells were incubated with purified CEACAM5 for different time points and subjected to immunoblotting for anti-phosphoLcK mAb. At 15′ CEACAM5 induce phosphorylation of LcK. Data are representative of three independent experiments. (d) Flow cytometry analysis of p-Lck staining in human peripheral CD8⁺ T cells and CD4⁺ T cells stimulated with Sup1, mAb CD8 and CEACAM5 purified peptide for different time points. H₂O₂ represents the positive control. Data are representative of five independent experiments.