Characterisation of microglial inflammation. (A) Representative confocal immunohistochemistry of APP [V717I] mice revealed that Il-1β and Il-6 colocalized with activated CD11b-positive microglial cells at 3 month. (B) At 16 month CD11b positive cells were almost exculsively detected in close proximity to Aβ1–42 positive plaques. At this time point, CD11b-positive and plaque associated microglia were also found to be colocalized with Il-1β and Il-6. (C) RT-PCR analysis was performed with frontal cortex brain lysates and is being displayed from two single animals at each age (3 and 16 month) for Il-1β, Il-6, MCSF-R, MHCII and TGFβ-1 and showed increased gene transcription at 16 months. (D) Densitometry of PCR products of APP [V717I] mice at 3 (open bars) and 16 months (filled bars) for the indicated inflammatory molecule. RT-PCR for GAPDH served as control. (n = 6, ANOVA followed by a TUKEY test, ***p < 0.001. Bar graphs in A-B are = 25 μm).