Intercellular adhesion molecule 3 (ICAM-3), also known as CD50, is a member of the immunoglobulin superfamily that binds to the leukocyte integrins LFA-1 (CD11a/CD18) and αd/β2.ICAM-3 is expressed on leukocytes and epidermal Langerhans cells.ICAM-3 is a transmembrane glycoprotein expressed by leukocytes as the the counter-receptor for lymphocyte function-associated antigen (LFA)-1 integrin.ICAM-3 regulates the affinity of LFA-1 for ICAM-1 and induces T-cell activation and proliferation, in addition to acting as an adhesion molecule for the contact of T-cells with antigen-presenting cells.ICAM-3 plays an important role in the initiation of the immune response by T-cells and antigen-presenting cells.CD50 molecules play an important role in the T lymphocyte function plays a role in the maturation process of T lymphocytes, and its expression is increased during the maturation process of T lymphocytes.