Abstract

Malignant lymphoma (ML) was Induced in eight of nine rabbb inoculated by oral spray of the cell-free pellets from SI-IIA culture (MLV-ll-transformed leukocyte cell line of the Cynomolgus-producing Epsteln-Barr virus (EBV)-related herpesvirus) after 64–141 days. None of the rabbits inoculated with EBV from B-95–8 cells or HTLV-II from MOT cells developed ML. Malignant lymphomas were usually of diffuse, large-cell or mixed type. HTLV-II infection was excluded by the polymerase chain reaction (PCR) and the particle agglutination test. EBV-encoded RNA-1 and EBV-related DNA were detected in the tumor tissues by In situ hybridization and PCR, respectively. Anti-viral capsid antigen of EBV antibody (anti-VCA) was observed 3 weeks after oral inoculation of Si-IIA cell-free pellets. Polymerase chain reaction revealed continuous detection of EBV-related virus DNA in the peripheral blood leukocytes from 3 days after oral inoculation. These results show that ML induced orally wtth SI-IIA cell-free pellets was caused by EBV-related herpesvirus harbored by Si-IIA cells. Oral spray of EBV from B-95–8 also induced EBV Infection in rabbits, which was confirmed both by the presence of anti-VCA and by PCR. These oral infection and mallgnant lymphoma induction systems of rabbit using EBV-related virus from Si-IIA or human EBV are useful animal models for the study of EBV infection and EBV-related lymphomas in humans.