The 9EG7 antibody reacts with the 130-kDa integrin β1 chain (CD29). CD29 is expressed on the cell surface as a heterodimer with one of the distinct integrin α chains. With α1 through α6 (CD49a through CD49f), it forms the VLA-1 through VLA-6 complexes, respectively, and with αv (CD51), it forms αvβ1 integrin. It also associates with the integrin α7 α8 and α9 chains in non-lymphoid tissues. As a result, CD29 has a broad tissue distribution, including lymphocytes, endothelia, smooth muscle, and epithelia. 9EG7 mAb has been shown to inhibit both the α6β1-mediated binding of lymphocytes to endothelial cells and the adhesion mediated by activated, but not unactivated, α4β1-integrin. The source of the immunogen was mouse lymph node-derived endothelial cell line TME.