Distribution of the β1 subgroup of the integrins in human cells and tissues

Abstract

We studied the distribution of the β1 integrin subfamily in human tissues and cells by light microscopy, electron microscopy, and immunoblotting, using monoclonal antibody DH12, previously shown to react with the β1 subunit of the human fibronectin receptor. Crossreaction with the other β subunits of the integrin family, which have 45% and 47% primary amino acid sequence identity with the β1 subunit, was excluded, as MAb DH12 did not react with the β2 subunit in granulocytes and the β3 subunit in thrombocytes. Reactivity with the anti-β1 antibody was found in skin, lung, heart, striated and smooth muscle, blood cells, liver, kidney, intestine, spleen and placenta. Thus, cells of mesodermal, ectodermal, and entodermal origin express the β1 subunit. In skin fibroblasts cultured in vitro, β1 subunit was also detected intracellularly. The wide distribution of the β1 family, originally detected in activated T-lymphocytes after prolonged culture in vitro, contrasts with the restricted distribution of the β2 integrins on leucocytes.