CMV-INDUCED CLASS-II ANTIGEN EXPRESSION IN VARIOUS RAT ORGANS

Cytomegalovirus (CMV) is thought to trigger acute or chronic allograft rejection by inducing the expression of MHC class II antigens in the graft. This induction may be mediated by gamma-interferon or directly by CMV. In this study, we have investigated which structures in the ra t kidney, liver, and heart are responsive to CMV-induced class II expr ession in vivo. Rats were infected with rat CMV, the organs were harve sted during the acute phase of infection, and the virus was demonstrat ed by culture from each organ. Direct CMV antigen detection was perfor med on frozen sections to demonstrate the detailed localization of CMV in the organs. In the kidney, CMV antigens were found in the vascular endothelium, in tubular cells, and scattered in the glomeruli. In the liver, the vascular structures and parenchyma contained CMV antigens. In the heart, CMV antigens were seen only in the capillary endotheliu m. Class II antigen expression was demonstrated by a monoclonal antibo dy and immunoperoxidase techniques. The induction of class II molecule s was recorded in exactly the same cellular structures as those in whi ch CMV antigens were detected.