CD4⁺CD28⁺regulatory T cells in Sjogren's syndrome

Excerpt

SS is a chronic autoimmune exocrinopathy chiefly affecting the salivary and lachrymal glands. The authors have previously established a murine model for SS in NFS/sld mice thymectomised 3 days after birth. The a-fodrin protein was identified as an organ-specific autoantigen in salivary gland tissue. In this study the authors investigate a mechanism of active suppression mediated by regulatory T cells in their model of SS. The authors identify a novel population of regulatory T cells expressing CD28; this key co-stimulatory molecule is expressed on the T cell surface and interacts with ligands B7.1/B7.2 (CD80/86) expressed on the surface of antigen presenting cells (APCs). CD28 delivers the critical 'second signal' to T cells following ligation of the T cell receptor 'first signal'. A number of studies have demonstrated that CD28 co-stimulation of T cells is involved in development of collagen-induced arthritis and experimental autoimmune encephalomyelitis. To investigate active suppression mediated by regulatory T cells involved in autoantigen-specific inhibition of immune responses in a murine model of SS. …