CMV isolated from infected decidua induces a ligand for the CEACAM1 on infected HFF cells. (a) Staining of HFF cells infected with clinical CMV strain with CD99-Ig or with CEACAM1-Ig. No staining was observed when proteins were omitted, indicated by the horizontal line. FSC, forward scatter. (b) IL-2 secretion from BW or BW/CEACAM1ζ cells coincubated with HFF-infected cells for 48 hours. The average of two experiments is shown.