CD11/CD18 belongs to the integrin family of proteins. It is heterodimeric cell surface receptor expressed on all leukocytes. CD18, in association with integrin α chain CD11a, CD11b, and CD11c forms LFA-1, Mac-1, and αXβ2, respectively, and plays an important role in leukocyte adhesion. CD11/CD18 complexes bind ICAM-1 (CD54), ICAM-2 (CD102), ICAM-3 (CD50), iC3b, and fibrinogen. Clone m24 binds the extended/open high affinity conformation of CD11a/CD18. The antibody can be used as a reporter of the activation state of the integrin receptor in response to exposure to Mg2+ or Mn2+.