Background：The KMI6 antibody reacts with the 130-kDa integrin B1 chain （CD29）. CD29 is expressed on the cell surface as a heterodimer with one of the distinct integrin achains. With a1 through a6 （CD49a through CD49f）, it forms the VLA-1 through VLA-6 complexes, respectively, and with av （CD51）, it forms avB1 integrin. It also associates with the integrin a7, a8, and a9 chains in non-lymphoid tissues. As a result, CD29 has a broad tissue distribution, including leukocytes, endothelia, smooth muscle, epithelia, and oocytes. The epitope recognized by the KMI6 mAb can be detected by immunoblot in unreduced extracts from a variety of cells and tissues having a number of different B1-integrin heterodimer combinations. However, the epitope is not well expressed on the surface of the majority of hematopoietic cells. It is detected on the surface of fetal liver cells, some bone marrow stromal cells, and some cultured hematopoietic cell lines, including P815 and PA6. Surface expression of the CD29 epitope recognized by mAb KMI6 on thymocytes and T lymphocytes appears to be developmentally regulated, and KMI6 antibody enhances the adhesion of KMI6 thymocytes to fibronectin and laminin.
