Ablation of nasal-associated lymphoid tissue does not affect focal ischemic brain injury in mice.

Stroke is a devastating disease with a strong inflammatory component. It has been shown that part of this response is mediated by IL17+ γδT cells. γδT cells constitute a lymphocyte population with innate features that mainly populates epithelial surfaces including skin, intestine, and airways. We have shown that in the context of stroke, T cells migrate from the small intestine to the meninges but whether they can migrate from other epithelial surfaces is still unknown. Because of its proximity, one possible source of stroke-associated IL17+ γδT cells could be the Nasal-Associated Lymphoid Tissue (NALT) from which T cells could migrate along olfactory nerve sheaths through the cribriform plate into the brain and/or meninges. In order to study the role of NALT as a source for immune cells and/or inflammatory mediators in the context of stroke, we analyzed the effect of NALT ablation on immune cell infiltration and infarct volume after stroke. Infarct volume analysis did not show any significant difference between sham and NALT-ablated animals. In addition, no significant differences were found in immune cell infiltration in the brain or meninges of stroke animals subjected to NALT or Sham-ablation surgery. In conclusion, NALT ablation does not affect ischemic brain damage or immune cell infiltration in the meninges or brain after stroke.