Figure 3

CD137L signaling activates microglia in vivo . (A) CD137L is required for activation of microglia in vivo. Cortex and spinal cord tissue sections of WT and CD137L^-/- mice with EAE were immunohistochemically stained with an isotype control antibody or for Iba-1 (brown). Shown in the inset is a close-up of a single Iba-1-positive microglia cell in the cortex of a WT mouse with EAE. (B) Quantification of Iba-1⁺ microglia in the spinal cords and cortices of WT and CD137L^-/- mice with EAE. Evaluated were three fields from two sections each using the Metamorph NX Software. Depicted are means ± standard deviations. (C) CD137 is expressed in the CNS during EAE. Spinal cord of naïve WT mice and WT mice with EAE was sectioned and stained with an isotype control antibody or for CD137 (brown). (D) The presence of CD137L is required for oligodendrocyte apoptosis in EAE. Tissue sections from the dorsal column of the spinal cord and the white matter of the cerebellum of WT and CD137L^-/- mice with EAE were stained for oligodendrocytes using a Cy3-labeled anti-Nogo-A antibody (red). Apoptosis was detected by TUNEL staining (green). Nuclei were visualized by DAPI (blue). The yellow staining results from an overlay of red and green and indicates apoptotic oligodendrocytes. Magnification: 40×. (E) Quantification of apoptotic oligodendrocytes in the cerebellum of WT and CD137L^-/- mice with EAE. Evaluated were three fields from two sections each using the Metamorph NX Software. Depicted are means ± standard deviations.