FIG. 9.

Phenotypic assessment of TUNEL-positive cells in the thymus of macaque RM2. Streck tissue fixative buffer-fixed, paraffin-embedded thymic tissue from macaque RM2 obtained prior to infection (A) or 65 weeks postinfection at necropsy (B) was assessed. The TUNEL assay was used to identify cells containing low-molecular-weight DNA fragments (green) indicative of apoptosis. Macrophages were identified by the antibody to CD68 (red). Cells staining positive for both TUNEL and anti-CD68 are depicted in yellow and orange. Cells were also stained with DAPI (blue) to identify all nuclei. The arrow and inset indicate a macrophage (yellow/orange) surrounding what appears to be an apoptotic T cell.