Impact of IVIg on the interaction between activated T cells and microglia

When human microglia are co-cultured with activated human T lymphocytes, several cytokines become up-regulated in significant quantities. This condition can also occur at sites of inflammation in autoimmune inflammatory diseases of the central nervous system (CNS), including multiple sclerosis (MS), where T cells infiltrate the brain tissue and come in proximity to microglia. Therefore, T cell-microglia interaction is a potential avenue of drug therapy to decrease neuroinflammation. An immunomodulator used in autoimmune disorders is intravenous immunoglobulins (IVIg). The mechanisms of IVIg activity in diseases such as MS remain unclear. Here, we report that the application of IVIg to activated T cells leads to their decreased ability to engage microglia. As a result of IVIg treatment of T cells, there were reduced levels of tumor necrosis factor-a and interleukin-10 in T cell-microglia co-culture. Our results add to the understanding of how IVIg may affect inflammation of the CNS. [Neurol Res 2006; 28: 270–274]