Reelin immunoreactivity in the aged human hippocampal formation. A) Reelin (G10 antibody) immunoperoxidase labeling in combination with hematoxylin (Ehrlich) counterstaining. The tissue section was obtained from an 88 year-old ND individual. The color-coding represents the areas included in the stereological analysis: 1=fornix, 2=stratum lacunosum moleculare (SLM), 3=molecular layer of subiculum, 4=molecular layer of pre/parasubiculum, 5=molecular layer of entorhinal cortex (EC). B) Higher magnification view of Reelin-positive deposits in the fornix. Arrow points to a filled deposit, arrowhead indicates a hollow deposit. C) Reelin (G10) immunoperoxidase labeling combined with toloidinblue counterstaining in the fornix border area. Tissue section was obtained from an 80 year-old AD patient. D) Control staining using isogenic IgGs (mouse anti-human CD45 antibody) following antigen retrieval (microwave irradiation in citrate buffer plus pepsin pretreatment) and Hematoxylin (Harrys) counterstaining. Brain section was obtained from a 79 year-old ND individual. Arrowhead points to a CD45-negative deposit, insert represents a CD45-positive lymphocyte associated with a brain capillary. E) Control staining without primary antibody following antigen retrieval and Hematoxylin/Eosin counterstaining. Brain section was obtained from an 81 year-old ND individual. Arrowhead points to an immune-negative deposit. Scale bars: A = 2 mm, B - D = 30 μm.