Neutrophils express many surface adhesion molecules, including CEACAM1, CEACAM3, CEACAM4, CEACAM6 and CEACAM8 glycoproteins, which play an important role in biological functions of neutrophils such as adhesion, phagocytosis, oxidative burst and degranulation. CEACAM3 activates neutrophils and initiates phagocytosis as a result of binding to bacterial Opa protein. In addition, CEACAM1 and CEACAM6 can delay apoptosis. All neutrophil CEACAMs, except for CEACAM3, can stimulate adhesion of neutrophils to endothelium. One CEACAM family member, CEA, which is not expressed by neutrophils, displays strong chemotactic activity, and probably can prime and/or activate neutrophils to adhesion. Induction of CEACAM signaling can be initiated by dimerization of CEACAMs and/or phosphorylation of their cytoplasmic domains. CEACAM signaling is often associated with an increase in the cytoplasmic calcium level.