The role of CD28null T cells in autoimmune diseases

Abstract

During aging and chronic infections, T cells lose the costimulatory molecule CD28 and show various similarities with NK cells, such as proinflammatory functions characterized by the production of high levels of IFN-gamma, TNF-alpha, and IL-2. They are cytotoxic and resistant to apoptotic cell death. An increase in CD4+CD28null T cells represents an important amplification mechanism in several autoimmune diseases, leading to more severe disease symptoms. CD8+CD28null T cells are also detrimental for the host, but have been shown to have some beneficial effects as well. We aim to further elucidate the role of both CD8+CD28null and CD4+CD28null T cells in immunopathology, and hypothesize that CD4+CD28null T cells actively contribute to chronic inflammatory diseases such as MS.