FIG. 6.

IDO in situ hybridization (silver grains) in SIVE, combined with immunohistochemistry (brown diaminobenzidine product). (A) IDO mRNA is observed in the nodules largely within the white matter (no primary antibody). (B) Immunohistochemical staining for GFAP reveals no colocalization with astrocytes. (C) Immunohistochemical staining with the FA2 antibody (for SIV Gag) reveals colocalization with SIV-expressing cells. (D to F) Immunohistochemical staining with the HAM56 antibody reveals colocalization with cells of the macrophage lineage. Data from monkeys 321 (A to D; magnification, ×200) and 323 (E and F; magnification, ×400) are shown.