Colocalization of CXCL9/Mig mRNAs with SIV virion RNA⁺ cells and CD68⁺ monocytes/macrophages in lymph nodes from rhesus macaques.

Lymph node tissue sections from macaques in the acute phase of infection (A-C, M5299) or AIDS (E-G, M5199) were hybridized in situ simultaneously with a ³⁵S-labeled riboprobe specific for CXCL9/Mig and a pool of digoxigenin-labeled riboprobes specific for SIV. SIV viral RNA⁺ cells appear purple, whereas the CXCL9/Mig signal is a more diffuse distribution of black silver grains. Autoradiographic exposure times were kept to 2 days to maintain visualization of the SIV viral RNA⁺ cells in a lower plane of focus. Parallel simultaneous ISH with the sense control probes are shown for comparison (C,G). Lymph node tissue sections from a macaque with AIDS (M5199) were simultaneously hybridized in situ with a CXCL9/Mig-specific, ³⁵S-labeled riboprobe and stained immunohistochemically for the monocyte/macrophage marker, CD68 (D). ISH signal is the diffuse distribution of black silver grains, whereas the CD68 signal is the deposition of an insoluble brown precipitate. Arrows indicate several double-positive cells. ISH with the sense control probe, with simultaneous staining for CD68, is shown in panel H. The bar in panel A is equivalent to 100 μm and applies to panels A and E. The bar in panel B is equivalent to 40 μm and applies to panels B-D and F-H. Sections were counterstained with nuclear fast red (A-C, E-G) or hematoxylin (D, H). Original magnifications, × 100 (A, E) and × 400 (B-D, F-H).