Carcinoembryonic antigen inhibits neutrophil activation by N-formyl-methionyl-leucyl-phenylalanine

Carcinoembryonic antigen (CEA) is a surface glycoprotein expressed in human epithelial cells and is released from their surface, especially during colorectal cancer. Frequently, colorectal cancer is accompanied by inflammation, where tumor-infiltrating neutrophils play an important role. CEA was also found to be a strong chemotactic agent for neutrophils. The purpose of this study was to find out if CEA can enhance neutrophil priming and activation. Primed neutrophils were activated by N-formyl-methionyl-leucyl-phenylalanine (formyl-MLP) and the resulting oxidative burst was measured luminometrically. Unexpectedly, in vitro priming of neutrophils by CEA, alone or preceded by LPS, inhibited subsequent activation of these cells by formyl-MLP. CEA may have anti-inflammatory properties in vivo.