Integrin beta 2/CD18
Integrin beta 2, the CD18 antigen, is the beta chain shared by the four leukocyte beta2 integrins LFA-1, Mac-1, p150,95 (CD11c/CD18) and alpha D beta2. Expressed on all leukocytes, the chain partners with CD11a, CD11b, CD11c or CD11d to mediate adhesion to ICAM molecules, complement-opsonized particles and extracellular matrix during immune and inflammatory responses. Inside-out signaling converts the chain's extracellular domain from bent to extended active conformations that support firm leukocyte arrest on endothelium. Mutations in the ITGB2 gene cause leukocyte adhesion deficiency type I, a syndrome of recurrent bacterial infections and impaired pus formation.
