Invitrogen™ CD18 Monoclonal Antibody (IVA35), Alexa Fluor™ 488

CD18, also known as the integrin beta 2 subunit, is a 90-95 kDa type I transmembrane protein expressed on all leukocytes. It heterodimerizes with the alpha chains of CD11a, CD11b, CD11c, and CD11d to form various leukocyte (beta2) integrins, which are crucial for cellular adhesion and signaling. The CD18/CD11a complex, known as lymphocyte function-associated antigen-1 (LFA-1), plays a significant role in cellular adhesion and inflammatory reactions. CD18 also forms heterodimers with CD11b (Mac-1, CR3), CD11c, and CD11d, contributing to the processes of cell adhesion and cell-surface mediated signaling. These integrins are essential for proper leukocyte migration and mediating intercellular contacts. The absence of CD18 leads to leukocyte adhesion deficiency type I (LAD1), a condition characterized by impaired leukocyte migration. Severe reduction in CD18 expression can result in the development of a psoriasiform skin disease. CD18 is also a target of Mannheimia (Pasteurella) haemolytica leukotoxin, which can mediate leukotoxin-induced cytolysis. Defects in the CD18 gene are the cause of LAD1, and two transcript variants encoding the CD18 protein have been identified. The integrin-mediated responses are often a composite of the functions of its individual subunits, highlighting the importance of CD18 in immune function and disease.