Figure 3.

Relationship of the ratio of HMW-MAPs in the pellet/supernatant to the levels of AD P-tau in the pellet. The levels of MAP1 or MAP2 were determined in the 200,000 × g supernatant (Supt) and the 27,000 to 200,000 × g pellet (Pellet) from brain homogenates of 12 (MAP2) to 13 (MAP1) AD cases (•) and four Huntington disease cases (○). The levels of AD P-tau also were determined in the 27,000 × g to 200,000 × g fraction from the same brains by radioimmuno-slot blot using Tau-1 as the primary antibody (18). The AD P-tau values are expressed as cpm of the ¹²⁵I secondary antibody used. The Pellet/Supt ratios of the HMW-MAPs were obtained from the means of triplicate assays determined at three different concentrations. The levels of the MAPs correlate directly with the levels of AD P-tau in the 27,000 × g to 200,000 × g pellet, and levels of the HMW-MAPs in the 200,000 × g supernatant correlate inversely with the AD P-tau in the pellet. The Pellet/Supt ratios of the HMW-MAPs show a significant direct correlation with the AD P-tau levels (p < 0.05).