Rat astrocytes express interferon-gamma immunoreactivity in normal optic nerve and after nerve transection.

Astrocytes are pivotal components of immune reactions in the CNS. We further support this notion by the localization of the lymphokine interferon-gamma (IFN-gamma), which plays an important role during immune responses, to astrocytes in rat optic nerve (ON). Astrocytes identified by glial fibrillary acidic protein immunoreactivity were IFN-gamma positive in normal and transected ON while oligodendrocytes did not express IFN-gamma immunoreactivity. These findings indicate that astrocytes can generate important signals which orchestrate immunoinflammatory responses in the brain.