Detection of αS by ELISA and Western blot in mice inoculated with different concentrations of whole brain homogenates. A. Detection by ELISA of αSD with both LB509 and PSer129 antibody in sick M83 mice following inoculation with different concentrations of brain homogenates (5, 1 or 0.2%, P2), and age-matched uninoculated mice. For the 5% brain homogenate, the signal is statistically lower than for the 1% and 0.2% brain homogenates (**, p = 0.01). B. Western blot detection of αS with PSer129 antibody in the ultracentrifugation pellets in second passage experiments at different concentrations (experiments 3–5). As observed in ELISA, lower levels of αSD were detected in the pellets prepared from mice inoculated with the 5% brain homogenate, in comparison with most of the mice inoculated with the 1% and 0.2% brain homogenates. In contrast, comparable levels of αS were detected by clone 42 antibody in crude brain homogenates and in the supernatants obtained after ultracentrifugation. Comparable amounts of brain materials were loaded in each lane, as shown by an anti-β-actin antibody used as a loading control. Ages at death of the mice are indicated below the graphs.