β 2 Integrins As Regulators of Dendritic Cell, Monocyte, and Macrophage Function.

Emerging evidence suggests that the β integrin family of adhesion molecules have an important role in suppressing immune activation and inflammation. β integrins are important adhesion and signaling molecules that are exclusively expressed on leukocytes. The four β integrins (CD11a, CD11b, CD11c, and CD11d paired with the β chain CD18) play important roles in regulating three key aspects of immune cell function: recruitment to sites of inflammation; cell-cell contact formation; and downstream effects on cellular signaling. Through these three processes, β integrins both contribute to and regulate immune responses. This review explores the pro- and anti-inflammatory effects of β integrins in monocytes, macrophages, and dendritic cells and how they influence the outcome of immune responses. We furthermore discuss how imbalances in β integrin function can have far-reaching effects on mounting appropriate immune responses, potentially influencing the development and progression of autoimmune and inflammatory diseases. Therapeutic targeting of β integrins, therefore, holds enormous potential in exploring treatment options for a variety of inflammatory conditions.