Aβ oligomers reduce cell viability, co-administered nAbs-Aβ do not attenuate cell death. Primary microglia cells were treated with Aβ42 oligomers, cell viability was measured using the MTT assay. To investigate the effect of nAbs-Aβ, microglial cells were pre-incubated for 30 minutes with different concentrations of nAbs-Aβ. Viability of untreated cells was referred to as 100% viability. Experiments were performed at least three times, independently. nAbs-Aβ, naturally occurring autoantibodies against amyloid-β; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide.