Effect of brain cells on the activation of T lymphocytes using in vitro co-culture system

초록

Recently a large variety of immune cells have been found in brain of steady-state mice and the portions of immune cells were dramatically changed after brain inflammation. Especially, T cells play an important role in neuro-inflammation. However, because of the limited T cell numbers in brain it is difficult to study T cell activation in vivo. Therefore, we established in vitro co-culture system between lymphocytes and brain cells (neurons or astrocytes) and analyzed the phenotype of T cells and levels of cytokine expression. Embryonal cortex neurons were co-cultured with lymphocytes from spleen and lymph node. For the activation of T cells, lymphocytes were activated by anti-CD3/CD28 antibodies. In the presence of neurons, the portion of effector CD44+CD62L- T cells were increased but cytokine levels (IL-2, IL-4, IL-6, IL-13, IL-17, IFN-γ) in culture media were decreased. Similar to neuron culture, astrocytes also inhibited IFN-γ production, however, IL-6 expression was induced. When we re-stimulated T cells after co-culture with neurons, the percentages of the IFN-γ producing T cells and phosphorylation of STAT1 expressions were decreased. The result suggests that brain cells can influences the intrinsic signaling of T cells. The detail mechanisms, how brain cells affect the T cell signaling, should be elucidated in future.