Fig. 10

Low dose PHF (1 μg/ml) increased the phosphorylated tau/NeuN ratio, which was prevented by 4E6. a, b Immunoblots of samples treated with 1 μg/ml PHF alone or with a 4E6 or b IgG1, reacted with a P-Ser199 antibody. c In cells treated with 1 μg/ml PHF and 4E6, the PHF alone and Ab → PHF groups showed significantly higher phosphorylated tau levels compared to untreated control samples (165 and 185 % above control, p < 0.0001 for both). The PHF + Ab and PHF → Ab groups were significantly lower (91 and 112 % control, p < 0.0001 for both) than the PHF alone samples. d All of the IgG groups showed significantly higher average phospho-tau levels than the untreated controls (79, 119, and 94 % above control, p < 0.0001 for all) after 7 days. None of the groups were significantly different compared to the PHF alone samples. e As above, NeuN levels were used to control for cell loss, and the pattern of results seen in 4E6 treated cells remained. The PHF alone and Ab → PHF groups had significantly higher phospho-tau/NeuN ratios than untreated samples (1.46 and 1.9 fold higher, p < 0.0001). The PHF + Ab and PHF → Ab groups had significantly lower phospho-tau levels than the PHF alone samples comparable to untreated controls. f Correcting for NeuN levels, the same pattern of results in cells treated with control IgG was observed. All groups showed significantly higher levels of phospho-tau/NeuN relative to untreated controls (2, 3.9 and 1.5 fold increase in the PHF + Ab, PHF → Ab, and Ab → PHF groups, p < 0.0001 for all) and no difference relative to the PHF alone samples