Cell-cell contacts with epithelial cells modulate the phenotype of human macrophages

Interactions of macrophages with epithelium represent one of the pathways i nvolved in regulating local immune mechanisms. We studied the effect of cel l-cell contact with an epithelial monolayer on the phenotype of macrophages . Human monocytes and THP-1 macrophages were co-cultured with monolayers of human bronchial epithelial cells (HBECs), the alveolar type III-like cell line A549, renal adenocarcinoma epithelial cells (RA), and the lung fibrobl ast strain HFL-1. The expression of CD11b, CD14, CD54, and HLA-DR was measu red by immunocytochemistry and flow cytometry and showed epithelial cell in duction of CD54 and HLA-DR in monocytes and of all antigens in THP-1 cells. Co-culture with fibroblasts did not change the phenotype of macrophages. S eparation by a filter insert inhibited most of the effects. Culture superna tants did not induce prominent phenotypic changes. Cell-cell contacts with epithelium appear to be of importance in regulating the phenotype of macrop hages.