Leukocyte infiltration in the optic nerve of mice with ON. Double immunohistochemistry for the astrocyte-specific marker GFAP (red) and the pan-leukocyte marker CD45 (green) in 10-μm thick cryostat-cut sections of the optic nerve of WT and GFAP-IκBα-dn mice under naïve conditions and at various times after induction of EAE. Nuclei were labeled with DAPI. White arrows: isolated CD45+ leukocytes. Scale bar = 20 μm.