Fig. 6

EGCG suppresses macrophage infiltration and immune activation in the rectal mucosa of SHIV-infected macaques. a Morphological observation of the microstructure of the rhesus macaque rectum. Architecture of the rectal mucosa of rhesus macaques as examined by hematoxylin and eosin staining. Magnification ×200. b–e Immunohistochemistry staining of the cell infiltration and chronic immune activation in rhesus macaques intra-rectally treated with PBS or EGCG. EGCG (5 mM, 2 ml) or PBS (2 ml) was delivered to the rectum of rhesus macaques for 10 min prior to the challenge with SHIV_SF162P3N (10 TCID₅₀). Rectal tissues from two macaques were collected at autopsy (96 h post-infection). Cell infiltrates were demonstrated by immunohistochemistry staining with anti-CD3 (b) or anti-CD68 (c) antibody. Tissue activation was examined by staining with anti-CD163 (d) or anti-HLA-DR (e) antibody. The positivity of mucosal tissue for CD3⁺, CD68⁺, CD163⁺, and HLA-DR⁺ cells in the rectum mucosa were quantified using the Aperio Image Scope software. The solid yellow lines in d, e were used to designate regions, including the epithelium, lamina propria and intestinal glands of the rectal mucosa and submucosa, for algorithm analysis. Dotted yellow lines excluded the enclosed regions for the calculation. The positive cells within the mucosa and submucosa were counted per high-power field. At least two cross-sectioned rectal segments with different proximity to the anus were scanned and analyzed. Original magnification ×200. Data are shown as mean ± SD, which were analyzed using the two-tailed Student’s t-test. *P < 0.05 and **P < 0.01