Immunohistochemical staining of HIV and CMV coinfected brain tissue. IHC staining of archival human hippocampus brain tissue coinfected with HCMV from an HIV-infected patient. (A/B) Brain tissue IHC-stained for HIV Gag) using True Blue (Kirkegaard & Perry Laboratories, Gaithersburg, MD, USA) as a substrate for immunoperoxidase. Photographs in A and B were taken at 200x and 400x magnification, respectively. (D/C) IHC-stained brain tissue for the HCMV MIE gene protein using True Blue as an immunoperoxidase substrate. Photographs were at 200x and 400x magnification. (E) Brain tissue IHC dual-stained for the pericyte marker NG2 proteogylcan using 3,3-diaminobenzidine (DAB) staining cells brown and CMV MIE gene protein using Vector Red (Vector Laboratories, Burlingame, CA, USA) as a substrate for alkaline phosphatase (dual-stained indicated by arrows). This photograph was taken at 200x magnification. (F) Brain tissue dual-stained by IHC for NG2 proteoglycan and HCMV MIE gene protein showing a cell with a brown-colored cytoplasm and a red nucleus. This image was taken at 600x magnification. All images were taken with a Nikon TE2000S microscope fitted with a CCD camera (Nikon, Tokyo, Japan). CMV, cytomegalovirus; DAB, 3,3-diaminobenzidine; IHC, immunohistochemistry; HCMV, human cytomegalovirus; MIE, major immediate early protein; NG2, neuron-glial antigen 2.