For intracellular staining see more of GM-CSF, isolated leukocytes were incubated with 50 ng/mL PMA, 500 ng/mL ionomycin, Golgi-Plug (1 μL/mL) containing brefeldin A in RPMI-1640 at 37°C for 4 h. Thereafter,

cells were stained with rat antimouse CD4-FITC, rat antimouse CD45-V450, fixed and permeabilized with Cytofix/Cytoperm (BD), and stained with rat antimouse GM-CSF-PE (BD). Apoptotic and dead CD4+ T cells were detected by staining with 7-AAD and CD4-allophycocyanin. Fas expression on CD4+ T cells was analyzed by staining with hamster antimouse Fas-PE and CD4-FITC. Controls were stained with isotype-matched control antibodies. All antibodies and reagents were obtained from BD Biosciences (Heidelberg, Germany) unless otherwise mentioned. Flow cytometry was performed on a FACScan (BD Biosciences), and the data were analyzed with WinMDI or Cell Quest software. Primary astrocytes Ku-0059436 were isolated from 1- to 2-day-old newborn mice and cultured as published before [43]. To obtain pure astrocytes, cells were harvested from astrocyte cultures and stained with rat antimouse CD11b-PE. Pure astrocytes (CD11b−) were then separated from CD11b+ microglia with a FACSVantage cell sorter (BD). Neuronal cultures were obtained according to Lenz et al. [44]

with slight modifications. Briefly, pregnant female mice were sacrificed by cervical dislocation at gestational day 18.5, and dissociated cells of each embryonic brain were cultivated in flasks coated with poly-L-lysine in Neurobasal medium supplemented with B27 (Invitrogen) and 500 μM L-glutamine (Gibco). The purity of cultures for neurons was ≥98%, as determined by immunofluorescence

staining for Casein kinase 1 neuron-specific class III β-tubulin. DNA was isolated from sorted astrocytes and microglia, respectively, as well as from cultured neurons using a DNA isolation kit (Qiagen, Germany). For the detection of FasL expressed on the surface of astrocytes, mixed astrocyte/microglia cultures were stained with mouse antimouse FasL-PE and CD11b-FITC. Controls were stained with isotype-matched control antibodies. For histology on paraffin sections, mice anesthetized with methoxyflurane were perfused with 0.1 M PBS followed by 4% paraformaldehyde in PBS, spinal cords were processed and stained with hemalum and eosin, cresyl violet, and luxol fast blue. In addition, paraffin sections were used for immunohistochemical demonstration of GFAP, neurofilament, Mac3, and CD3 (Serotec, Düsseldorf, Germany) by an ABC protocol as described [45]. Total mRNA was isolated from the spinal cords of nonimmunized and MOG35–55- immunized mice (RNeasy kit, Qiagen, Germany) at day 15 and day 22 p.i., respectively. SuperScript reverse transcriptase kit with oligo (dT) primers (Invitrogen, Germany) was used to generate cDNA from total mRNA.