Decreased expression of MAP-2 and GAD in the brain of cats infected with feline immunodeficiency virus

HIV-1 infection is often complicated by the dysfunction of central nervous system (CNS). Degenerative neuronal changes as well as neuronal loss have been documented in individuals with acquired immunodeficiency syndrome. Feline immunodeficiency virus (FIV) causes similar CNS manifestation and FIV infected cats provide an animal model for human immunodeficiency virus infection in humans. In this study, we examined the brain of FIV-infected cats and controls with immunohistochemical techniques using antibodies to microtubule-associated protein 2 (MAP-2) and glutamic acid decarboxylase (GAD). We found a significant decrease in expression of MAP-2 and GAD in neurons of infected animals compared to controls. In contrast, the expression of neurofilaments and glial fibrillary acidic protein was rather increased. The changes observed in the brain were similar to those seen in humans undergoing the normal aging process as well as those suffering from neurological diseases like Alzheimer's disease and other dementing disorders. These changes in the feline brain give insight into the deleterious effects of FIV on the CNS.