Molecular Interactions between T Cells and Fibroblast-Like Synoviocytes

• Published in: The American journal of pathology Vol. 171; no. 5; pp. 1588 - 1598
• Main Authors: Tran, Chinh N, Lundy, Steven K, White, Peter T, Endres, Judith L, Motyl, Christopher D, Gupta, Raj, Wilke, Cailin M, Shelden, Eric A, Chung, Kevin C, Urquhart, Andrew G, Fox, David A
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.11.2007
• Subjects: Pathology
• ISSN: 0002-9440; 1525-2191
• DOI: 10.2353/ajpath.2007.070004

The mechanism of fibroblast-like synoviocyte (FLS) transformation into an inflammatory phenotype in rheumatoid arthritis (RA) is not fully understood. FLS interactions with invading leukocytes, particularly T cells, are thought to be a critical component of this pathological process. Resting T cells and T cells activated through the T-cell receptor have previously been shown to induce inflammatory cytokine production by FLS. More recently, a distinct population of T cells has been identified in RA synovium that phenotypically resembles cytokine-activated T (Tck) cells. Using time lapse microscopy, the interactions of resting, superantigen-activated, and cytokine-activated T cells with FLS were visualized. Rapid and robust adhesion of Tck and superantigen-activated T cells to FLS was observed that resulted in flattening of the T cells and a crawling movement on the FLS surface. Tck also readily activated FLS to produce interleukin IL-6 and IL-8 in a cell contact-dependent manner that was enhanced by exogenous IL-17. Although LFA-1 and ICAM-1 co-localized at the Tck-FLS synapse, blocking the LFA-1/ICAM-1 interaction did not substantially inhibit Tck effector function. However, antibody blocking of membrane tumor necrosis factor (TNF)-α on the Tck surface did inhibit FLS cytokine production, thus illustrating a novel mechanism for involvement of TNF-α in cell-cell interactions in RA synovium and for the effectiveness of TNF-α blockade in the treatment of RA.