Figure 2.

IL-33 expression by CNS resident cells in mouse brain and spinal cord. Tissues from C57BL/6 mice were sectioned and immunohistochemically stained for the expression of IL-33 (brown), and astrocytes (GFAP), neurons (NeuN) and microglia (Iba-1) (all blue) within the (A) corpus callosum and (B) hippocampus and IL-33 co-localization assessed. RSG, retrosplenial granular cortex; CC, corpus callosum; DG, dentate gyrus; CA1-3, hippocampus. (C) In spinal cord, the majority of IL-33 expressing cells are localized to the GM, with lower levels present in the WM. IL-33 is expressed by GFAP⁺ astrocytes in both GM and WM regions with lower level co-localization with neurons and microglia in the GM and, GM/WM, respectively. Arrowheads indicate IL-33⁺ cells, arrows indicate NeuN, GFAP or Iba-1⁺ cells and asterisks indicate double positive cells. GM, gray matter; WM, white matter. Scale bars represent 100 μm.