A triple staining procedure to evaluate phagocytic role of differentiated astrocytes

To determine whether phagocytic activity is affected by a viral infection known to induce astrocyte differentiation, a triple procedure (PAP labeling for GFAP, PAS reaction for added baker's yeast cells and hematoxylin for nuclear staining of the whole monolayer) was applied to Junin virus-inoculated cultures, as well as matched controls. The three-step staining simplified yeast cell count for subsequent statistical analysis, which discerned preferential uptake by differentiated rather than immature astrocytes. Accordingly, greater cell maturation induced by Junin virus was concomitant with early enhancement of phagocytic activity.