Promotion of microglia-mediated clearance of Aβ is dependent on lysosomal degradation. To study the role of lysosomal degradation in microglia-mediated Aβ clearance, the ex vivo assay was performed in the presence of Baf, an inhibitor of lysosomal degradation pathway. Baf inhibited microglia-mediated Aβ clearance (A, n = 3-6) as Aβ deposits remained mostly intact in sections treated with Baf (B). IVIG could partially restore microglia-mediated Aβ clearance halted by Baf. In the presence of Baf, 20 μM IVIG treatment resulted in low clearance and mostly of diffuse Aβ deposits only (A, B, n = 3-4, p < 0.05). Dense (arrows) and diffuse (arrowheads) Aβ deposits are shown in the subiculum. Scale bar 50 μm.