Brain interference: Revisiting the role of IFNγ in the central nervous system

Interferon gamma (IFNγ) is a pro-inflammatory cytokine, first described as a secreted molecule capable of interfering with viral replication. Since then, numerous other important actions in the context of the immune response to invading pathogens (including those invading the brain) have been ascribed to this pleiotropic cytokine. Nevertheless, the precise role of IFNγ in neuropsychiatric and neurodegenerative disorders, and its possible contribution to the regulation of normal brain function, remains enigmatic. This review integrates and considers current knowledge about IFNγ actions with accumulating evidence of its importance on neurocytogenesis, synaptic plasticity and neurodegeneration within the framework of brain health and disease.