CCL5 and Parkinson disease: When the phosphorylation of LCK and ZAP70 was inhibited, the expression of the LFA-1 protein on the surface of Th17 cells was significantly reduced, and CCL5-treated MPTP-injected mice that were treated with PP2 exhibited a reduction in the number of Th17 cells in the SN, a reduction in the number of lost DA neurons, and significant improvements in behavioral deficits, with a significant reduction in PD symptoms.