CX3CL1 suppresses microglia activation: Micrographs of OX-6 positive cells (MHCII; a marker for actived microglia) show a large increase in OX-6 staining in the control treated animals 5 weeks after a 6-OHDA in to striatum (A). Twenty-eight days infusion of CX3CL1 3 ng (B), CX3CL1 30 ng (C), or CX3CL1 90 ng (D), beginning 7 days after the insult with 6-OHDA show a clear reduction in OX-6 staining. Bar denotes 0.5 mm. Arrow denotes ameboid microglial cell (Panel A). Quantification of OX-6 immunoreactivity, by the Cavalieri method, found a significant decrease in OX-6 expression when exogenous CX3CL1 was administered (30 ng and 90 ng) as compared to the heat inactivated control (E). One way ANOVA testing [F(3,19) = 4.172, p = 0.0232]. Asterisk denotes significance (* P < 0.05) of Tukey post-hoc analysis compare to HI-CX3CL1 group.