Lymphocyte-Synovial Cell Interactions: A Role for β1 and β3 Integrin-Mediated Adhesion to Cellular Fibronectin

The interactions of lymphocytes with cultured synovial cells derived from rheumatoid arthritis patients were examined. A number of lymphoid cell lines bound to these cells. The adherence of several of these lines was inhibited by antibodies to fibronectin. The adherence of the T cell leukemia Jurkat was sensitive to inhibition by antibodies to the fibronectin receptors α4β1 and α5β1. The adherence of the β1 integrin negative B cell line RPMI 8866 was inhibited by antibodies to the vitronectin receptor, αvβ3. The interactions of several other cell lines with synovial cells appeared to be independent of this fibronectin-dependent pathway. These results indicate that multiple potential adhesion pathways for cellular interactions in the tissues may exist. The adherence to cell-associated fibronectin may play a contributory role in such processes for certain lymphocyte subsets.