IMMUNOHISTOCHEMICAL DETECTION OF THE EPSTEIN-BARR VIRUS-ENCODED LATENT MEMBRANE-PROTEIN 2A IN HODGKINS-DISEASE AND INFECTIOUS-MONONUCLEOSIS

We describe two new monoclonal antibodies specific for the Epstein-Bar r virus (EBV)-encoded latent membrane protein 2A (LMP2A) that are suit able for the immunohistochemical analysis of routinely processed paraf fin sections. These antibodies were applied to the immunohistochemical detection of LMP2A in Hodgkin's disease (HD). LMP2A-specific membrane staining was seen in the Hodgkin and Reed-Sternberg (HBS) cells of 22 of 42 (52%) EBV-positive MD cases, but not in 39 EBV-negative HD case s, In lymphoid tissues from patients with acute infectious mononucleos is (IM), interfollicular immunoblasts were shown to express LMP2A. Thi s is the first demonstration of LMP2A protein expression at the single -cell level in EBV-associated lymphoproliferations in vivo. The detect ion of LMP2A protein expression in HD and IM is of importance in view of the proposed role of this protein for maintaining latent EBV infect ion and ifs possible contribution for EBV-associated transformation, B ecause LMP2A provides target epitopes for EBV-specific cytotoxic T cel ls, the expression of this protein in HRS cells has implications for t he immunotherapeutic approaches to the treatment of HD. (C) 1997 by Th e American Society oi Hematology.