Fig. 3.
Soluble fractions of native plaques induce microglial reactivity. Bright-field photomicrographs of rat microglia cultures exposed to peak S1 (A) or peak S5 (B) and immunostained for the presence of Aβ. As shown, aggregates of Aβ are found throughout the cultures incubated with peak S5. Scale bar, 25 μm. Phase photomicrographs show cultured microglia as process-bearing cells with spinous surfaces typical of nonreactive cells, despite exposure to peak S1 (C). In contrast, microglia exposed to peak S5 retract processes and take on a reactive cell morphology similar to that found in AD brain (D). Scale bar, 5 μm.