Increased microgliosis characteristic of progressive EAE is decreased after anti-IL-6 treatment. Total number of macrophages (CD45hiCD11b+) (A) and microglia (CD45loCD11b+) (B) within the CNS of WT and GFAPγR1Δ mice treated with α-IL-6 or α-β-gal mAb at day 32 post immunization. Percentage of BrdU-positive macrophages (CD45hiCD11b+) (C) and microglia (CD45loCD11b+) (D) in WT and GFAPγR1Δ mice treated with α-β-gal or α-IL-6 analyzed at day 32 post immunization by flow cytometry. Data represent the mean ± SEM of two separate experiments with n = 4 per group per experiment. Statistics calculated with one-way ANOVA with Bonferroni post-test with *P < 0.05; **P < 0.01. (E) Microglia activation, characterized by MHC class II expression within CD45loCD11b+ cells, analyzed at day 32 post immunization by flow cytometry in WT, GFAPγR1Δ + α-β-gal, and GFAPγR1Δ + α-IL-6 mice. (F) Galectin-1 and heme oxygenase-1 mRNA expression within the brain of GFAPγR1Δ mice treated with α-β-gal or α-IL-6 at day 32 post immunization. Data represent the mean ± SEM of four individual mice per group. Statistics were calculated with by a two-tailed unpaired t test with *P < 0.05.