Flow cytometric analysis of major histocompatibility complex (MHC) class II antigen expression on brain cells from borna disease virus-infected rats without an intervening in vitro culture step

Borna disease virus (BDV) infects astrocytes in the Lewis rat brain. BDV-infected astrocytes have been shown to express MHC class II in vitro but not in vivo. Using a sensitive fluorescence-activated cytometric technique, we now report the detection of MHC class II on freshly harvested S100- positive cells from BDV-infected rat brain, without an intervening in vitro culture step. These data support the hypothesis that astrocytes from BDV- infected rats express MHC class II on their surface and, thus, are potential participants in the encephalitic response to BDV infection.