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Portland, OR, United States

Offner H.,Neuroimmunology Research RandD 31 | Offner H.,Oregon Health And Science University | Hurn P.D.,University of Texas at Austin
Translational Stroke Research | Year: 2012

Although inflammatory immune cells clearly contribute to the development of middle cerebral artery occlusion (MCAO) in mice, the failure to block neutrophil-associated injury in clinical stroke trials has discouraged further development of immunotherapeutic approaches. However, there is renewed interest in a possible protective role for regulatory T and B cells that can suppress inflammation and limit central nervous system damage induced by infiltrating pro-inflammatory cells. Our failure to implicate CD4 +FoxP3 + T cells in limiting brain lesion volume after MCAO turned our focus towards regulatory B cells known to mediate protection against other inflammatory CNS conditions. Our results clearly demonstrated that B cell-deficient mice developed larger infarct volumes, higher mortality, and more severe functional deficits compared to wild-type mice and had increased numbers of activated T cells, macrophages, microglial cells, and neutrophils in the affected brain hemisphere. These MCAO-induced changes were completely prevented in B cell-restored mice after transfer of highly purified WT B cells but not IL-10-deficient B cells. Our novel observations are the first to implicate IL-10-secreting B cells as a major regulatory cell type in stroke and suggest that enhancement of regulatory B cells might have application as a novel therapy for this devastating neurologic condition. © 2012 Springer Science+Business Media, LLC.

Dziennis S.,Oregon Health And Science University | Mader S.,Oregon Health And Science University | Akiyoshi K.,Oregon Health And Science University | Ren X.,Oregon Health And Science University | And 9 more authors.
Metabolic Brain Disease | Year: 2011

Stroke induces a biphasic effect on the peripheral immune response that involves early activation of peripheral leukocytes followed by severe immunosuppression and atrophy of the spleen. Peripheral immune cells, including T lymphocytes, migrate to the brain and exacerbate the developing infarct. Recombinant T-cell receptor (TCR) Ligand (RTL)551 is designed as a partial TCR agonist for myelin oligodendrocyte glycoprotein (MOG)-reactive T cells and has demonstrated the capacity to limit infarct volume and inflammation in brain when administered to mice undergoing middle cerebral artery occlusion (MCAO). The goal of this study was to determine if RTL551 could retain protection when given within the therapeutically relevant 4 h time window currently in clinical practice for stroke patients. RTL551 was administered subcutaneously 4 h after MCAO, with repeated doses every 24 h until the time of euthanasia. Cell numbers were assessed in the brain, blood, spleen and lymph nodes and infarct size was measured after 24 and 96 h reperfusion. RTL551 reduced infarct size in both cortex and striatum at 24 h and in cortex at 96 h after MCAO and inhibited the accumulation of inflammatory cells in brain at both time points. At 24 h post-MCAO, RTL551 reduced the frequency of the activation marker, CD44, on T-cells in blood and in the ischemic hemisphere. Moreover, RTL551 reduced expression of the chemokine receptors, CCR5 in lymph nodes and spleen, and CCR7 in the blood and lymph nodes. These data demonstrate effective treatment of experimental stroke with RTL551 within a therapeutically relevant 4 h time window through immune regulation of myelin-reactive inflammatory T-cells. © 2011 Springer Science+Business Media, LLC.

Chen Y.,Oregon Health And Science University | Bodhankar S.,Neuroimmunology Research RandD 31 | Bodhankar S.,Oregon Health And Science University | Murphy S.J.,Oregon Health And Science University | And 6 more authors.
Metabolic Brain Disease | Year: 2012

Recent evidence emphasizes B-cells as a major regulatory cell type that plays an important role in limiting the pathogenic effects of ischemic stroke. The aim of the current study was to extend this initial observation to specifically examine the infiltration of regulatory B-cells and to determine if the effect of B-cells to limit the inflammatory response to cerebral ischemia is mediated by their action centrally or peripherally. Our data demonstrate the increased presence of a regulatory B-cell subset in the affected hemisphere of wild-type mice after middle cerebral artery occlusion (MCAO). We further explored the use of a novel method of stereotaxic cell delivery to bypass the blood brain barrier (BBB) and introduce CD19+ B-cells directly into the striatum as compared to peripheral administration of B-cells. Infarct volumes after 60 minutes of MCAO and 48 hours of reperfusion were determined in B-cell deficient μMT-/- mice with and without replacement of either B-cells or medium. Infarct size was significantly decreased in cerebral cortex after intrastriatal transfer of 100,000 B-cells to μMT-/- mice vs. controls, with a comparable effect on infarct size as obtained by 50 million B-cells transferred intraperitoneally. These findings support the hypothesis that B-cells play a protective role against ischemic brain injury, and suggest that B-cells may serve as a novel therapeutic agent for modulating the immune response in central nervous system inflammation after stroke. © Springer Science+Business Media, LLC 2012.

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