Amplification of regulatory T cells using a CD28 superagonist reduces brain damage after ischemic stroke in mice.
OBJECTIVE
Neuroinflammation plays an important role in ischemic brain injury. Regulatory T cells (Treg) are important endogenous immune modulators. We tested the hypothesis that Treg amplification with a CD28 superagonistic monoclonal antibody (CD28SA) reduces brain damage in murine cerebral ischemia.


METHODS
Cerebral ischemia was induced by coagulation of the distal middle cerebral artery or by 60 minutes filament occlusion of the proximal middle cerebral artery in C57BL6 mice. 150 μg CD28SA was injected intraperitoneally 3 or 6 hours after ischemia onset. Outcome was determined by infarct volumetry and behavioral testing. Brain-infiltrating leukocyte subpopulations were analyzed by flow cytometry and immunohistochemistry 3 and 7 days after middle cerebral artery occlusion.


RESULTS
CD28SA reduced infarct size in both models and attenuated functional deficit 7 days after stroke induction. Mice treated with CD28SA increased numbers of Treg in spleen and brain. Tregs were functionally active and migrated into the brain where they accumulated and proliferated in the peri-infarct area. More than 60% of brain infiltrating Treg produced interleukin-10 in CD28SA compared with 30% in control.


CONCLUSIONS
In vivo expansion and amplification of Treg by CD28SA attenuates the inflammatory response and improves outcome after experimental stroke.
From the Department of Neurology, University Heidelberg, Germany (S.-Y.N., E.M., A.L., R.V.); Institute for Stroke and Dementia Research, Munich, Germany (A.L.); Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (A.L.); Institute for Virology and Immunobiology, University Würzburg, Germany (T.H.); and Division of Brain Sciences, Imperial College, London, UK (R.V.).
Shin-Young
SY
Na
From the Department of Neurology, University Heidelberg, Germany (S.-Y.N., E.M., A.L., R.V.); Institute for Stroke and Dementia Research, Munich, Germany (A.L.); Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (A.L.); Institute for Virology and Immunobiology, University Würzburg, Germany (T.H.); and Division of Brain Sciences, Imperial College, London, UK (R.V.).
Eva
E
Mracsko
From the Department of Neurology, University Heidelberg, Germany (S.-Y.N., E.M., A.L., R.V.); Institute for Stroke and Dementia Research, Munich, Germany (A.L.); Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (A.L.); Institute for Virology and Immunobiology, University Würzburg, Germany (T.H.); and Division of Brain Sciences, Imperial College, London, UK (R.V.).
Arthur
A
Liesz
From the Department of Neurology, University Heidelberg, Germany (S.-Y.N., E.M., A.L., R.V.); Institute for Stroke and Dementia Research, Munich, Germany (A.L.); Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (A.L.); Institute for Virology and Immunobiology, University Würzburg, Germany (T.H.); and Division of Brain Sciences, Imperial College, London, UK (R.V.).
Thomas
T
Hünig
From the Department of Neurology, University Heidelberg, Germany (S.-Y.N., E.M., A.L., R.V.); Institute for Stroke and Dementia Research, Munich, Germany (A.L.); Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (A.L.); Institute for Virology and Immunobiology, University Würzburg, Germany (T.H.); and Division of Brain Sciences, Imperial College, London, UK (R.V.). Roland.Veltkamp@med.uni-heidelberg.de.
Roland
R
Veltkamp
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001921:Brain / Q000187:drug effects / Q000276:immunology*; D002545:Brain Ischemia / Q000150:complications / Q000276:immunology; D018106:CD28 Antigens / Q000819:agonists*; D004195:Disease Models, Animal; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000276:immunology* / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D020521:Stroke / Q000209:etiology / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000276:immunology*
D000911:Antibodies, Monoclonal; D018106:CD28 Antigens
brain ischemia; regulatory T cells