Figure 6. Quantities of TGF-β–expressing CD163⁺/CD68⁺ cells increased with acute infection but not sustained in the chronically infected animals.

(A–D) Cells producing TGF-β in the frontal cortex, thalamus, and basal ganglia of macaque brain, after infection with SIV, were identified using anti–TGF-β antibodies costained with antibodies against macrophage lineage cells (CD163⁺/CD68⁺). Analysis of double-positive cells in the 3 brain regions combined (A) and in individual brain regions: frontal cortex (B), thalamus (C), and basal ganglia (D). Each data point indicates 1 animal, and the associated numerical value is the average number of cells counted in 15 HPFs at 40× under light microscope. (E and F) IHC images of negative control (E) and positive staining (single stained for CD163⁺/CD68⁺ cells in brown [black arrow]; double stained [blue arrow] for CD163⁺/CD68⁺ cells and TGF-β in brown and blue, respectively (F). Data are presented as mean ± SD. Statistical significance was calculated using a nonparametric Kruskal-Wallis test and the multiple comparisons were assessed using Dunn’s post hoc analysis. *P ≤ 0.05, **P ≤ 0.01. n = 3 (control, 7 dpi, chronic), n = 5 (14 dpi) (A–D). Scale bar: 20 μm (E and F).