Role of glutamate on T-cell mediated immunity.

The pivotal role that glutamate plays in the functioning of the central nervous system is well established. Several glutamate receptors and glutamate transporters have been extensively described in the central nervous system where they, respectively mediate glutamate effects and regulates extracellular glutamate levels. Recent studies have shown that glutamate not only has a role as neurotransmitter, but also as an important immunomodulator. In this regard, several glutamate receptors have recently been described on the T-cell surface, whereas glutamate transporters have reportedly been expressed in antigen presenting cells such as dendritic cells and macrophages. On the other hand, an increasing number of reports have described a protective autoimmune mechanism in which autoantigen specific T cells in the central nervous system protect neurons against glutamate neurotoxicity. This review integrates and summarises different findings in this emerging area. A role of glutamate as a key immunomodulator in the initiation and development of T-cell-mediated immunity in peripheral tissues as well as in the central nervous system is suggested.