Figure 2.

Analysis of spleen macrophage populations. Immunohistochemistry was performed on spleen sections for CD68 (gray), CD163 (red), CD163/CD68 (gray and red), and Mac387 (brown) macrophages in the white (A) and red pulp (B) of uninfected and SIV-infected macaques. Representative images are shown. Boxed insets show higher magnification of macrophages in the white (A) and red pulp (B) of uninfected and SIV-infected animals. C: A representative image of the white pulp in an uninfected macaque demonstrates the germinal center, mantle zone, marginal zone, and red pulp, as indicated by dashed line demarcations. D–G: To quantitate the presence of macrophages in spleen, numerical scores of 0 to 3 were assigned for each marker in the splenic regions and averaged. The fold-change of the mean scores for infected macaques was determined relative to uninfected controls, which was set to 1. The fold-change for CD68 (gray line with squares), CD163 (red line with circles), CD163/CD68 (purple line with diamonds), and Mac387 (yellow line with triangles) macrophages was determined for the germinal center (D), mantle zone (E), marginal zone (F), and red pulp (G) during the acute, asymptomatic, and chronic phases of infection. The acute (light shading), asymptomatic, and chronic (dark shading) phases of SIV infection are depicted. Cross-sectional study of independent groups of animals after euthanasia at each time point was performed and the data depicted using solid lines connecting data points for better visualization. Statistical significance was determined by Mann-Whitney test. P ≤ 0.05 versus the preceding day after inoculation for all comparisons. Data are expressed as means ± SD. ^∗P < 0.05 CD163 macrophages versus the preceding time point; ^†P < 0.05 CD163/CD68 macrophages versus the preceding time point; ^‡P < 0.05 Mac387 macrophages versus the preceding time point; and ^§P < 0.05 CD68 versus the preceding time point. Original magnifications: ×10 (A); ×20 (B and C).