Tregs play vital roles in suppressing atherogenesis. Pathological conditions reshape Tregs and increase Treg-weakening plasticity. It remains unclear how Tregs preserve their function and how Tregs switch into alternative phenotypes in the environment of atherosclerosis. In this study, we observed a great induction of CD4 +Foxp3 + Tregs in the spleen and aorta of ApoE –/– mice, accompanied by a significant increase of plasma IL-35 levels. To determine if IL-35 devotes its role in the rise of Tregs, we generated IL-35 subunit P35–deficient (IL-35P35–deficient) mice on an ApoE –/– background and found Treg reduction in the spleen and aorta compared with ApoE –/– controls. In addition, our RNA sequencing data show the elevation of a set of chemokine receptor transcripts in the ApoE –/– Tregs, and we have validated higher CCR5 expression in ApoE –/– Tregs in the presence of IL-35 than in the absence of IL-35. Furthermore, we observed that CCR5 + Tregs in ApoE –/– have lower Treg-weakening AKT-mTOR signaling, higher expression of inhibitory checkpoint receptors TIGIT and PD-1, and higher expression of IL-10 compared with WT CCR5 + Tregs. In conclusion, IL-35 counteracts hyperlipidemia in maintaining Treg-suppressive function by increasing 3 CCR5-amplified mechanisms, including Treg migration, inhibition of Treg weakening AKT-mTOR signaling, and promotion of TIGIT and PD-1 signaling.