Peripheral and intracerebral T cell immune response in cats naturally infected with Borna disease virus

Borna disease virus (BDV) is a neurotropic agent with capacity to cause encephalomyelitis in a wide range of animal species, including horses and cats. Recent studies also point to a link between BDV and human neuropsychiatric disorders. The pathogenesis of Borna disease (BD) has been proposed to be immune-mediated, mainly through the effects of cytotoxic T cells. We used flow cytometric analysis in order to characterize the peripheral and intracerebral T cell immune response in cats naturally infected with BDV, Our results show the presence of two different CD8+ cell populations (CD8+(low) and CD8+(high)) in the blood, spleen and brain of these cats. In the brain, CD8+(low) cells predominated over CD8+(high) cells. Since CD8+(low) cells have been suggested to represent a non-MHC-restricted T cell population, the recruitment of such cells to the brains of BDV-infected cats could possibly be of importance for the clearance of virus from neurones. (C) 1999 Elsevier Science B.V. All rights reserved.