Fig. 5

TUNEL positive cells are usually SIV-infected or in close proximity to SIV-infected cells

High-power view of neurovirulent SIV-infected macaque CNS show colocalization of TUNEL label and SIV antigen (A–D, closed arrows) or close proximity of TUNEL labelled cells with SIV positive cells (B and D, open arrows). TUNEL-labeled nuclei appear black, and SIV immunostaining appears light brown. TUNEL- and SIV-positive cells are often seen in areas of hypercellularity (B). SIV antigen is occasionally detected in the absence of TUNEL indicating the specificity of the double-labeling method. Scale bars are 20 µm (A and B) and 50 µm (C and D).