FIG. 6.

Pigtailed macaques with SIVE (enceph) have more infected macrophages in peripheral organs than macaques without encephalitis (no enceph). Organs obtained at necropsy were immunostained for CD68, CD3, and SIVgp110 and visualized by immunofluorescent confocal microscopy. Four observers enumerated the numbers of infected macrophages (CD68⁺/SIV-positive cells), infected T cells (CD3⁺/SIV-positive cells), and SIV-infected cells that did not colabel with either CD68 or CD3 (SIV-positive/CD3⁻/CD68⁻ cells). The black bars represent the median of infected cells enumerated for each group (each dot represents the enumeration from an individual field). (a and d) Liver and spinal cord. The median of infected macrophages was statistically significantly higher in macaques with SIVE than in macaques without encephalitis. More infected T cells were also enumerated in macaques with SIVE than in macaques without encephalitis. Macrophages were the most common SIV-infected cell in the spinal cord. (b, c, and f) Lung, small bowel, and thymus. The median number of infected macrophages was statistically significantly higher in macaques with SIVE than in macaques without encephalitis. Small numbers of SIV-infected cells that did not colabel with CD68 or CD3 were found in the thymus, small bowel, and lung. The small bowel had the highest number of infected macrophages of all organs examined. (e) Spleen. The median number of infected macrophages was statistically significantly higher in macaques with SIVE than in macaques without encephalitis. *, P < 0.05; **, P < 0.01; ***, P < 0.001.