CD11c (p150, alphaX integrin subunit) forms complex with CD18 (beta2 integrin subunit) and is expressed mainly on tissue macrophages and dendritic cells. CD11c binds to complement fragment iC3b, fibrinogen, VCAM-1 and ICAM-2 or e.g. CD90. Like other beta2 integrins, CD11c/CD18 plays roles in cell migration and phagocytosis. Moreover, interaction of CD11c/CD18 with plasminogen regulates plasmin activities, and interaction with heparin counteracts binding of iC3b.