Neuroinflammation and vaccination strategy in Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by loss of dopaminergic neurons in the substantia nigra. Other neuropathological hallmarks include α-synuclein aggregation, Lewy bodies, Lewy neurites, and neuroinflammation in the brain. It has been proposed that the α-synuclein pathology starts in the gut with the non-motor symptoms, and then it propagates to the brain via the vagus nerve causing motor symptoms. The immune cells in the brain, namely microglia and astrocytes trigger innate immune responses and the infiltrating T cells are a part of adaptive immune response. The production of cytokines and chemokines enhances neuroinflammation. In the periphery, the monocytes and CD4+ and CD8+ T cells activation increases, causing inflammation. As inflammation is the key pathological hallmark of PD, it has emerged as an attractive target for immunotherapies. The active and passive immunotherapeutic drugs target the α-syn aggregates to overcome neuroinflammation and other motor and non-motor symptoms.