VLA-2 is a collagen receptor on endothelial cells.

In order to identify cell-substrate adhesion receptors on vascular endothelium, murine monoclonal antibodies (MoAb) were raised against human umbilical vein endothelial cells (HUVE). One anti-HUVE MoAb, RMAC11, identified the adhesion receptor VLA-2 as it immunoprecipitated a non-covalently linked heterodimer of 160 kD and 130 kD, which was identical to the heterodimer immunoprecipitated by the anti-VLA-2 MoAb, 12F1 and 5E8. Furthermore, proteolytic peptide maps of the VLA-2 alpha- and beta-chains were highly homologous with those of the RMAC11-recognized molecule. However, unlike other VLA-2 MoAb, RMAC11 also identified an 85 kD band which migrated to 90 kD under reducing conditions. This band was most likely a fragment of the 160 kD alpha-chain as a similar alpha-chain derived fragment has been demonstrated in the immunoprecipitates of some VLA-4 reactive monoclonals. However the possibility that this may be a novel molecule associated with VLA-2 has not been excluded. In vitro assays of HUVE adhesion to collagen types 1 and 4, laminin and fibronectin showed that RMAC11 blocked adhesion to collagen (types 1 and 4) and laminin, but had no effect on HUVE adhesion to fibronectin, confirming that VLA-2 is a collagen and laminin receptor for HUVE.