Figure 3: BOSC cells were transiently transfected with expression vectors containing either the cDNA of CEACAM1, CEACAM3-CEACAM8 or CEACAM19-21. Recognition of CEACAM4 was tested on CHO cells stably transfected with a CEACAM4 expressionvector. Expression of the constructs was confirmed with monoclonal antibodies known to recognise the corresponding proteins (CEACAM1: 4/3/17, CEACAM3, 4: D14HD11, CEACAM5: 26/3/13, CEACAM6: 9A6, CEACAM7: BAC2, CEACAM8: GM-2H6, CEACAM19-21: anti-myc, green curves). An irrelevant monoclonal antibody served as a negative control (black curves). Forspecificity testing, protein G purified D14HD11 was tested on all CEACAM transfectants. A positive signal was obtained with CEA-CAM1, CEACAM3, CEACAM4, CEACAM5 and CEACAM6 expressing cells (red curves).

Figure 4: FACS analysis of BOSC23 cells using D14HD11. BOSC23 cells were transiently transfected with anexpression vector encoding either CEACAM1, 3, 4, 5, 6 (red curves) or an irrelevant protein (control transfectant: blackcurves). Binding of D14HD11 was detected with a PE-conjugated secondary antibody. A positive signal wasobtained only with CEACAM1, CEACAM3, CEACAM4, CEACAM5 and CEACAM6 expressing cells.

Figure 1: Domain organization of the human CEACAM family. The CEACAM family consists of two subgroups, the CEACAM and the PSG subgroup. CEACAM family members are membrane bound by either via a transmembrane domain or a GPI anchor (green arrow) whereas the PSGs are secreted glycoproteins. N-linked glycosylation sites are shown as drum sticks. The IgV domains are shown. in red, the IgC domains in blue.