Fig. 2.

In situ hybridization. Detection of human cytomegalovirus (HCMV) nucleic acids using HCMV IE1 and whole genomic probe. First row: CMV-infected lung hybridized with (a) a nonsense DNA probe (negative control) and (b) poly-AAA probe (positive control); (c) HCMV IE1 probe demonstrates hybridization to large cytomegalic cells throughout the lung specimen. Second row: (d) GBM specimen hybridized with nonsense DNA probe and (e) poly-AAA antisense probe; (f) detection of HCMV IE1 in a GBM specimen shows hybridization of tumor cells throughout the specimen. Third row: (g) GBM specimen stained with nonsense whole genomic probe (negative control); (h) alu DNA probe (positive control) and (i) pan HCMV genomic DNA probe, demonstrating HCMV detection within tumor cells but not vasculature within the specimen. Fourth row: Competition experiment showing ability to block detection of IE1 hybridization using a 50-fold excess of unlabeled specific competitor DNA probe but not using an excess of the nonsense probe; (j) lack of detection with nonsense DNA probe; (k) HCMV IE1 antisense probe with 50-fold excess nonsense competitor probe; (l) HCMV IE1 antisense probe with 50-molar excess of IE1 competitor probe. Results show localization of HCMV DNA within GBM tumor cells and capacity to specifically compete hybridization with HCMV-specific competitor probe.