Lung epithelial lining fluid T cell subsets defined by distinct patterns of beta 7 and beta 1 integrin expression.

Integrins are heterodimeric cell-surface glycoproteins that mediate cell-cell and cell-matrix adhesion. We previously identified cDNA encoding a novel integrin beta subunit, beta 7, from bronchoalveolar lavage fluid (BALF) leukocytes. The beta 7 subunit protein is now known to associate with at least two integrin alpha subunits on lymphocytes. One beta 7 integrin, alpha 4 beta 7, mediates lymphocyte adhesion to endothelium and to fibronectin. The other known beta 7 integrin, alpha E beta 7, has recently been shown to mediate lymphocyte-epithelial cell adhesion in vitro. We used flow microfluorometry to analyze the expression of alpha 4 beta 7, alpha E beta 7, and other integrins on blood T cells and epithelial lining fluid T cells obtained from five healthy adult volunteers by bronchoalveolar lavage. alpha 4 beta 7 was the predominant beta 7 integrin on blood T cells, whereas alpha E beta 7 was predominant on BALF T cells. BALF T cells could be divided into alpha E beta 7- and alpha E beta 7+ subsets. Bet...