Malignant lymphomas induced by an Epstein-Barr virus-related herpesvirus from Macaca arctoides--a rabbit model.

Animal models for Epstein-Barr virus (EBV) are restricted to some species of new-world monkeys which develop malignant lymphoid tumours or benign lymphoproliferative diseases after virus inoculation. Similar pathological features were induced in rabbits by the EBV-related herpesvirus of Macaca arctoides (HVMA). In this study 17 of 32 rabbits infected with varying amounts of HVMA produced from MAL-1 cells developed lymphoproliferative disorders. In 13 rabbits high-grade malignant lymphomas were detected, 4 rabbits revealed the histopathological feature of lymphoid hyperplasia. These lymphoproliferations were shown to be associated with HVMA by PCR and by the expression of EBV-like RNAs (EBER) in 14 and 10 cases, respectively. The homology in the polymerase gene region between DNA from EBV and HVMA, and from HVMA and the malignant tissue was found to be 94.8% and 100%, respectively. All the infected animals produced antibodies to antigens corresponding to early and late EBV proteins. By studying the HVMA expression in MAL-1 cells EBV-like proteins expressed in latency (EBNA1 and EBNA2) and in the lytic cycle (VCA, EA) were detected. Our findings suggested that HVMA caused a symptomatic infection in rabbits with pathological features that fit the conditions of an animal model suitable for testing antiviral drugs and vaccines against EBV.