Interleukin 4 increases human synovial cell expression of VCAM-1 and T cell binding

Abstract

Objective - The effects were studied of interleukin 4 (IL-4) on T cell-synovial cell adhesion and on the expression of adhesion molecules on the surface of synovial fibroblast-like cells. Methods - The adhesion of T cells toward the synovial cells were measured by 53chromium-labelled adhesion assay. The expression of adhesion molecules on synovial cells were analysed by flowcytometry. Results - Stimulation of synovial cells with IL-4 increased T cell-synovial cells adhesion in a time- and dose-dependent manner. IL-4 considerably enhanced the expression of VCAM-1 on the surface of synovial cells, but not the expression of ICAM-1 and ELAM-1. The combination of IL-1β and IL-4 had no effect on the expression of ICAM-1 or VCAM-1 on the surface of synovial cells. The increased adhesion of T cells to IL-4 stimulated synovial cells was inhibited significantly by adding anti-VCAM-1 or anti-CD29 monoclonal antibody. Furthermore, anti-VLA-4α or the combination of anti-VLA-4α and anti-VCAM-1 antibodies blocked completely T-cell, binding to IL-4 stimulated synovial cells. Conlusions - These results suggest that the increased adhesion of T cells to IL-4-stimulated synovial cells is mediated by VLA-4/NCAM-1 pathway.