FIG 6.

Immunophenotype of SIV RNA⁺ cells in the inguinal LN. Cells containing vRNA were detected in tissue sections using in situ hybridization with fluorescently tagged antisense SIV-specific riboprobes and antibodies to phenotype cells using cell markers. The images are from 1 day p.i. (A and B), 7 days p.i. (C), and 14 days p.i. (D) (A, C, D) Tissues collected from animals inoculated with SIVmac251; (B) tissue collected from an animal inoculated with AT-2-inactivated SIV and necropsied at 1 day p.i. Arrows, representative SIV RNA⁺ cells (bright blue) located mostly in the T cell-rich paracortex (blue); arrowheads in panel B, extracellular vRNA within a B cell follicle; arrowheads in panel D, vRNA within macrophages. The vRNA signal is separated by a clear space from the surrounding macrophage cytoplasm, as if it were in a phagosome. Red, CD3⁺ T cells; green, p55⁺ endothelial cells and bone marrow-derived DCs; yellow, CD68⁺ macrophages; bright blue, SIV RNA; dark blue, DAPI staining of nuclear DNA. Bars = 20 μm.