Multiple sequence alignment was performed by Clustal W, using amino acid sequences of rat ACAM (rACAM; GenBank® accession number, AF302047), mouse ACAM (mACAM; AY326421), human ACAM (hACAM; AY326422), CAR (Hs.473417), BT-IgSF (Hs.112873), ESAM (Hs.173840), CTXL (Hs.112377), MGC44287 (Hs.177164), GPA33 (Hs.437229), JAM-A (Hs.414880), JAM-B (Hs.436494) and JAM-C (Hs.419149). Identical and similar amino acids are boxed in black and grey respectively. Signal sequences are indicated by broken lines. Transmembrane segments are underlined. Rabbit polyclonal serum was raised against a synthetic peptide at the C-terminal end (bold and underlined). N-glycosylation sites are indicated by closed circles. ACAM, CAR, BT-IgSF and CTXL share the motif D/EI/LREDXXXP (indicated by asterisks). The six cysteine residues, C1 to C6, forming disulphide bonds in V- and C2-type Ig domains, are indicated. The J-segment motif (VLV) is indicated by J.