MAC1 is necessary for Aβ-induced microglial activation. Mesencephalic neuron-glia cultures from MAC1+/+ and MAC1-/- mice were treated with vehicle medium (control group) or Aβ for 2 days. (A) Cultures were fixed after treatments. Microglia were visualized by immunostaining of the F4/80 antigen, a microglial marker. The images presented are representative of three independent experiments. Scale bar: 50 μm. (B) Western blot analysis of microglial activation. Cell lysates of cultures from MAC1+/+ and MAC1-/- mice were prepared 2 days after vehicle or 2.0 μM Aβ treatment and immunoblot analysis was performed for the measurement of Iba1 antigen. GAPDH was used as loading control. (C) The ratio of densitometry values of Iba1 and GAPDH was analyzed and normalized to respective control. Results are presented as mean ± SEM for three independent experiments. #: p < 0.05 compared with corresponding vehicle-treated controls. *: p < 0.05 compared with MAC1+/+ cultures after same treatments.