Parkinson's disease (PD) is the second most common neurodegenerative disease, with motor and non-motor symptoms being its main clinical manifestations. Neuroinflammation has been shown to involve in pathogenesis of PD. Regulatory T cells (Tregs) in PD exhibited reduction in number and suppressive activity. Existing methods to increase the Tregs remains challenging for clinical application because of the difficulty in Tregs expanding or serious side-effects. Therefore, new approaches still need to be explored to balance the amount and activity of Tregs. In this study, we assessed the protective effects of IL-2/anti-IL-2 complexes (IL-2C) on mouse models of PD induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). And the results showed that IL-2C significantly increased the number of Tregs both in spleen and brain, accompanied by reduced nigral dopaminergic neuron loss and behavioral defects. Besides, IL-2C also attenuated neuroinflammation as observed by diminished glial activation, fewer infiltration of CD4