Immunolocalization of HIV envelope gp120 in HIV encephalitis with dementia.

Numerous studies have shown that the HIV envelope glycoprotein, gp120, is a potent neurotoxin. However, its role in the pathogenesis of HIV dementia had been questioned due to the lack of demonstration of its presence in vivo. We now demonstrate conclusively the presence of gp120 by immunohistochemistry in the brain of patients with HIV encephalitis who also had dementia. A highly specific anti-gp120 polyclonal sera was used on formalin fixed tissue. Gp120 staining cells were predominantly perivascular and included macrophages, microglia and multinucleated giant cells. These studies provide an important missing link for the role of gp120 in the neuropathogenesis of HIV infection.