nAbs-Aβ enhance phagocytosis of Aβ oligomers in primary microglia. Histogram of the mean fluorescence intensity of FITC-Aβ and FITC-Aβ and nAbs-Aβ (0.1 μM) co-treated cells (A). (B) shows the means of three independent experiments. Values were normalized to FITC-Aβ42-treated cells. Cell lysates of Aβ42-treated cells were also subjected to western blot. To detect Aβ uptake, blots were probed with the monoclonal Aβ antibody 6E10. GAPDH was used as loading control (C). (D) shows the densitometric evaluation of three independent experiments; values are given normalized to GAPDH intensity. FITC, fluorescein isothiocyanate; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; nAbs-Aβ, naturally occurring autoantibodies against amyloid-β.