GFAP and Gliosis: The results revealed a similar reduction in plaque burden (measured by the number of plaques and by the area covered by the plaques) in the dentate gyrus (DG) and cortex, and in gliosis (measured by Glial Fibrillary Acidic Protein (GFAP)-immunoreactivity) in both anti-PD-1 and anti-PD-L1 treatment groups, as compared to the IgG-treated group (Fig. 2d–g).