Abstract T MP18: In Vivo Expansion of Regulatory T cells with Interleukin-2/Interleukin-2-antibody Complex Protects against Transient Ischemic Stroke
Background and Purpose: Our previous work documents the transfer of regulatory T cells (Tregs) in rodent models of ischemic stroke protects acute ischemic brain injury by regulating poststroke inflammatory response and thereby ameliorating BBB disruption. However, the low number of Tregs restricts the clinical feasibility of Treg transfer. Recently, in vivo expansion of Tregs with IL-2/IL-2-antibody complex (IL-2/IL-2Ab) was validated protective in autoimmune diseases model,renal ischemia reperfusion model and atherosclerosis. Here we investigate the beneficial effect of IL-2/IL-2Ab on ischemic stroke and decipher the underlying mechanisms.
Methods: IL-2/IL-2Ab or isotype IgG was ip injected into C57/BL6 mice for 3 consecutive days. The mice are then subjected to 60-minute middle cerebral artery occlusion (MCAO) or sham operation. Brain infarction, inflammation and neurological performance was assessed up to 7 days after reperfusion.
Results: Flow cytometry analysis reveals a marked increase of CD4+CD25+Foxp3+ Tregs in the blood, lymph nodes and spleens collected from IL-2/IL-2Ab-treated mice as compared to those from isotype-treated controls. Such Treg elevation could be observed since 3 days after IL-2/IL-2Ab injection and lasts until 7 days after MCAO. Immunochemistry staining confirms the increased number of Foxp3+ cells in the spleen at 3 days after MCAO in IL-2/IL-2Ab-treated mice. IL-2/IL-2Ab promotes function recovery up to 7 days after stroke, as revealed by significantly improved performance in corner test (n=6-9, ***p<0.001), rotarod test (n=8, **p<0.01), cylinder test (n=8, **p<0.01) and adhesive removal test (n=3, *p<0.05). Quantification of TTC staining and microtubule-associated protein (MAP2) staining shows reductions in brain infarct volume at 3 days (n=5-9,*p<0.05) and 7 days (n=7-9,*p<0.01), respectively, after MCAO. Meanwhile, we observed reduced infiltration of peripheral immune cells (CD3+ T cells, MPO+ neutrophils and F4/80+ macrophages) into the ischemic brain.
Conclusions: Our finding suggests that IL-2/IL-2Ab treatment is a novel and clinical feasible immune therapy to expand Treg population in vivo, reduce post-stroke inflammatory responses and protect against ischemic brain injury.
Author Disclosures: H. Zhang: None. P. Li: None. Y. Gao: None. J. Chen: None. X. Hu: None.
This research has received full or partial funding support from the American Heart Association, National Center.
- © 2015 by American Heart Association, Inc.