Figure 4

Reactivity of microglial cells and astrocytes after antibody-mediated demyelination. IB4-labeled microglial cells (A–C), 48 hours after the demyelinating insult, were more numerous in cultures subjected to the demyelinating treatment (C compared to A). Some of them contained vacuoles and were increased in size, suggesting a macrophagic state. Complement alone caused a slight microglial activation (B compared to A). Quantification of IB4-labeled microglial cells (D) expressing the labeled area as percent of untreated control cultures. Twenty aggregate sections per treatment were measured. Results were statistically evaluated for significance by the Kruskal-Wallis test followed by the Mann-Whitney test. (**P < 0.01, ***P < 0.001 compared with untreated control cultures). Astrocytes immunostained for GFAP (E–G) showed that demyelination caused enlarged astrocytic processes and increased immunostaining (G compared to E). Complement alone did not affect neither astrocytic morphology nor GFAP staining (F compared to E). A and E, untreated controls; B and F, complement treated (guinea pig serum, 25 μl/ml); C and G, treated with antibody (anti-MOG, 62.5 μg/ml) and complement. A–C: bar = 50 μm; E–G: bar = 10 μm.