Figure 3. Immunohistochemistry reveals CD33 expression in the brain and an increase frequency of stage III microglia/macrophages associated with rs3865444C.
(a) CD33+ microglia/macrophages (brown) are seen in sections of the dorsolateral prefrontal cortex from a subject with pathologically confirmed AD; they are found in the vicinity of amyloid deposits (red). (b) Adjacent sections labeled with anti-CR3/43 (top panel), a marker for microglia/macrophage, and anti-CD33 (bottom panel) demonstrate that the cells staining with anti-CD33 have the morphologic attributes of microglia/macrophage. (c) CD33 is expressed at all 3 stages of activation in microglia/macrophages in the brain. The density of stage 3 CR3/43+ microglia is increased in the inferior temporal region (d) and posterior putamen region (e) with the rs3865444C risk allele. Each circle represents a subject. The line represents the mean.