CD15 is 3-fucosyl-N-acetyllactosamine (3-FAL), also known as Lewis X, 3-FAL, X-hapten, and SSEA-1. CD15 is expressed on granulocytes and monocytes. It has also been shown to be expressed on Langerhans cells and some malignant cells. CD15 has been implicated in adhesion, as well as chemotaxis, phagocytosis, and bactericidal activity.