CD49b the integrin alpha 2 chain, associates with CD29 (integrin beta 1 chain) to form VLA-2 integrin complex, which plays a critical role in the processes of lymphocyte adhesion and activation. VLA-2 serves as a receptor for collagen, laminin, and fibronectin and also regulates the extracellular matrix synthesis and organization. CD49b has been used to identify NK cells, and coexpressed with CD223 (LAG-3) it identifies CD4+ T regulatory type 1 cells (Tr1) .