Fig. 2.

P301S v2H cells exhibit increased sensitivity to AD-derived tau seeds. The FRET assay was performed with successive dilutions of synthetic tau fibrils mixed with Lipofectamine 2000 (a) and without transfection reagent (b) (log scale), and of immunopurified tau from an AD brain with Lipofectamine 2000 (c). d–f) are expansions of the dose response curves of in (a–c), respectively. Lower limit of detection (LLD—defined as the lowest quantity of tau fibrils that produces a signal of FRET positivity statistically distinguishable from background, T-test, p < 0.05) with Lipofectamine-mediated synthetic fibril seeding was 10 amoles for all cell lines. For naked synthetic fibril seeding the LLD was 0.59 pmol for all cell lines, and with AD brain protein it was 1 ng for v1, 100 pg for v2L, and 10 pg for v2H (represent pre-IP quantities of total protein). Error bars are SEM of 3 technical replicates over which each sample was divided