IDCs are closely associated with SIV-infected cells in the lymph node paracortex.

(A-B) In situ hybridization for SIV RNA using antisense (A) and control (B) sense probes on a lymph node of a monkey with AIDS. (C) In situ hybridization for SIV RNA (black) was combined with immunohistochemistry for p55 protein (brown) to identify IDCs. Arrow identifies SIV RNA in a follicle. (D) Higher power image of the boxed area in panel C highlighting p55⁺ IDCs in close proximity to SIV-infected cells (arrows). F indicates follicle. Ab staining was detected using streptavidin-peroxidase with diaminobenzidine substrate. Tissues were counterstained with hematoxylin. Original magnification × 100 (A,B), × 200 (C), and × 400 (D).