(D) Immunofluorescence analysis of the old APPPS1 slice cultured alone (old alone) or in co-culture with young GM-CSF-/- brain slices (old co-culture) at 14 DIV and immunostained with CD68 (red) and M3.2 (green) reveals an increased number of core-only plaques upon co-culturing with young GM-CSF-/- brain slices. Scale bar: 50 µm.(E) Quantitative analysis of core-only plaques in the old APPPS1 slice cultured alone or in co-culture with young GM-CSF-/- brain slices (14 DIV) reveals an increased number of core-only plaques upon co-culturing of old APPPS1 brain slices together with young GM-CSF-/- brain slices. The values are expressed as percentages of core-only plaques from the total number of amyloid plaques. The values represent mean ± SEM from 3 independent experiments, each experiment including 3 independent slice culture dishes (***P < 0.001).(F) CD68 coverage in the old APPPS1 tissue (14 DIV) cultured alone or in co-culture with young GM-CSF-/- brain slices. CD68 coverage is increased upon co-culturing of old APPPS1 brain slices together with young GM-CSF-/- brain slices. The values are normalized to CD68 coverage of the old slice cultured alone and represent mean ± SEM from 3 independent experiments, each experiment including 2 independent slice culture dishes (*P < 0.05). 