A novel Epstein-Barr virus-like virus, HVMNE, in a Macaca nemestrina with mycosis fungoides

Epstein-Barr virus (EBV) infection of humans has been associated with the d evelopment of lymphoid malignancies mainly of B-cell lineage, although occa sionally T-cell lymphomas have been reported. We describe here the characte rization of a novel EBV-like virus (HVMNE) isolated from a simian T-cell ly mphotropic virus type I/II (STLV-I/II) seronegative pigtailed macaque (Maca ca nemestrina) with a cutaneous T-cell lymphoma. Immunohistochemistry studi es on the skin lesions demonstrated that the infiltrating cells were of the CD3(+)/CD8(+) phenotype. Two primary transformed CD8(+); T-cell lines were obtained from cultures of peripheral blood mononuclear cells (PBMC) and sk in, and, with time, both cell lines became interleukin-2-independent and ac quired the constitutive activation of STAT proteins. Polymerase chain react ion analysis of the DNA from the cell lines and tissues from the lymphomato us animal demonstrated the presence of a 536-bp DNA fragment that was 90% i dentical to EBV polymerase gene sequences, whereas the same DNA was consist ently negative for STLV-I/II sequences. Electron microscopy performed on bo th cell lines, after sodium butyrate treatment, showed the presence of a he rpes-like virus that was designated HVMNE according to the existing nomencl ature, In situ hybridization studies using EBV Epstein-Barr viral-encoded R NA probes showed viral RNA expression in both CD8(+) T-cell lines as well a s in the infiltrating CD8(+) T cells of skin-tissue biopsies. Phylogenetic analysis of a 465-bp fragment from the polymerase gene of HVMNE placed this virus within the Lymphocryptovirus genus and demonstrated that HVMNE is a distinct virus, clearly related to human EBV and other EBV-like herpesvirus es found in nonhuman primates. (C) 1999 by The American Society of Hematolo gy.