Priyadharshini Arunachalam1, Peter Ludewig1, Patrick Melich1, Thiruma Valavan Arumugam1, Christian Gerloff1, Immo Prinz1, Tim Magnus1, Mathias Gelderblom2. 1. From the Department of Neurology, University Medical Center Hamburg-Eppendorf, Germany (P.A., P.L., P.M., C.G., T.M., M.G.); Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore (T.V.A.); and Institute of Immunology, Hannover Medical School, Germany (I.P.). 2. From the Department of Neurology, University Medical Center Hamburg-Eppendorf, Germany (P.A., P.L., P.M., C.G., T.M., M.G.); Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore (T.V.A.); and Institute of Immunology, Hannover Medical School, Germany (I.P.). m.gelderblom@uke.de.
Abstract
BACKGROUND AND PURPOSE: Immune-mediated tissue damage after stroke evolves within the first days, and lymphocytes contribute to the secondary injury. Our goal was to identify T-cell subpopulations, which trigger the immune response. METHODS: In a model of experimental stroke, we analyzed the immune phenotype of interleukin-17 (IL-17)-producing γδ T cells and explored the therapeutic potential of neutralizing anti-IL-17 antibodies in combination with mild therapeutic hypothermia. RESULTS: We show that brain-infiltrating IL-17-positive γδ T cells expressed the Vγ6 segment of the γδ T cells receptor and were largely positive for the chemokine receptor CCR6 (CC chemokine receptor 6), which is a characteristic for natural IL-17-producing γδ T cells. These innate lymphocytes are established as major initial IL-17 producers in acute infections. Genetic deficiency in Ccr6 was associated with diminished infiltration of natural IL-17-producing γδ T cells and a significantly improved neurological outcome. In the ischemic brain, IL-17 together with tumor necrosis factor-α triggered the expression of CXC chemokines and neutrophil infiltration. Therapeutic targeting of synergistic IL-17 and tumor necrosis factor-α pathways by IL-17 neutralization and therapeutic hypothermia resulted in additional protective effects in comparison to an anti-IL-17 antibody treatment or therapeutic hypothermia alone. CONCLUSIONS: Brain-infiltrating IL-17-producing γδ T cells belong to the subset of natural IL-17-producing γδ T cells. In stroke, these previously unrecognized innate lymphocytes trigger a highly conserved immune reaction, which is known from host responses toward pathogens. We demonstrate that therapeutic approaches targeting synergistic IL-17 and tumor necrosis factor-α pathways in parallel offer additional neuroprotection in stroke.
BACKGROUND AND PURPOSE: Immune-mediated tissue damage after stroke evolves within the first days, and lymphocytes contribute to the secondary injury. Our goal was to identify T-cell subpopulations, which trigger the immune response. METHODS: In a model of experimental stroke, we analyzed the immune phenotype of interleukin-17 (IL-17)-producing γδ T cells and explored the therapeutic potential of neutralizing anti-IL-17 antibodies in combination with mild therapeutic hypothermia. RESULTS: We show that brain-infiltrating IL-17-positive γδ T cells expressed the Vγ6 segment of the γδ T cells receptor and were largely positive for the chemokine receptor CCR6 (CC chemokine receptor 6), which is a characteristic for natural IL-17-producing γδ T cells. These innate lymphocytes are established as major initial IL-17 producers in acute infections. Genetic deficiency in Ccr6 was associated with diminished infiltration of natural IL-17-producing γδ T cells and a significantly improved neurological outcome. In the ischemic brain, IL-17 together with tumor necrosis factor-α triggered the expression of CXC chemokines and neutrophil infiltration. Therapeutic targeting of synergistic IL-17 and tumor necrosis factor-α pathways by IL-17 neutralization and therapeutic hypothermia resulted in additional protective effects in comparison to an anti-IL-17 antibody treatment or therapeutic hypothermia alone. CONCLUSIONS: Brain-infiltrating IL-17-producing γδ T cells belong to the subset of natural IL-17-producing γδ T cells. In stroke, these previously unrecognized innate lymphocytes trigger a highly conserved immune reaction, which is known from host responses toward pathogens. We demonstrate that therapeutic approaches targeting synergistic IL-17 and tumor necrosis factor-α pathways in parallel offer additional neuroprotection in stroke.
Authors: Jonathan Howard DeLong; Sarah Naomi Ohashi; Kevin Charles O'Connor; Lauren Hachmann Sansing Journal: Semin Immunopathol Date: 2022-06-29 Impact factor: 11.759