Search

Objectives: To clarify characteristics on rabbit in vivo infec-tion with type 2 EBV nuclear antigen (EBNA-2)-de\eXed Ep-stein-Barr virus (P3HR-1-EBV) and compare infectious effica-cy of P3HR-1-EBV with previously reported prototype type 1 EBV from B95-8. Methods: Twelve Japanese White rabbits were inoculated with P3HR-1-EBV via intranasal or intrave-nous routes and autopsied on day 70-84. Results: In only 2 of 12 P3HR-1-EBV-inoculated rabbits, EBV-DNA was detected in peripheral blood mononuclear cells (PBMCs). ßomHI M rightward reading frame (BMRF)-l, EBNA-1 and ßamHI Z left-ward reading frame (BZLF)-1-vnRN/k were intermittently ex-pressed in PBMCs. In 1 infected rabbit with continuous de-tection of EBV-DNA in PBMCs, many EBER-1-positive lympho-cytes were observed in germinal centers and/or marginal zones in some follicles of the appendix, and for the first time a lymphocyte with EBER-1 expression infiltrating in the squa-mous cell layer of the tonsils was found. The other rabbit with a transient detection of EBV-DNA in PBMCs had no EBER-1-positive lymphocytes in the tissues examined. Few EBER-1-positive lymphocytes were detected in some rabbits with-out detection of EBV-DNA in PBMCs. Conclusions: P3HR-1-EBV showed less efficient infection in rabbits than EBV from the B95-8 cell line. However, a P3HR-1-EBV-inoculated animal model is meaningful because this is the first study of EBNA-2 function on in vivo EBV infection and it demonstrated the in vivo infectivity with lytic-type infection by EBNA-2-deleted EBV. [ABSTRACT FROM AUTHOR]

It has recently been shown that approximately 80% of Merkel cell carcinomas harbor a novel polyomavirus named Merkel cell polyomavirus (MCPyV). MCPyV has been detected in human tissue samples. However, detailed distribution of MCPyV in non-neoplastic Japanese human tissues remains unclear. To address this, we used single or real-time quantitative polymerase chain reaction (PCR) for 41 autopsy cases. PCR revealed MCPyV-DNA in non-neoplastic samples: total, 29/41 (71%); adult, 29/39 (74%); fetus or infant, 0/2; men, 24/28 (86%); women, 5/13 (38%); total human tissues, 66/572 (12%); skin, 8/15 (53%); adrenal gland, 9/33 (27%), and other 16 organs (4-25%). This study first reported the presence of MCPyV-DNA in non-neoplastic tissues of thyroid gland, adrenal gland, spleen, bone marrow, stomach, gallbladder, pancreas, heart, and aorta. PCR revealed that viral load ranged from 0.00026 to 0.22 in all MCPyV-positive tissues compared with Merkel cell carcinoma samples. These detailed PCR data showed higher prevalence of MCPyV infection in Japanese men than women (p = 0.004) and broad distribution of MCPyV with low viral load in more non-neoplastic human tissues than in the previous reports. These data provide valuable insights for further studies of MCPyV infection and MCPyV-related diseases. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Most humans become lifelong carriers of Epstein-Barr virus (EBV) by adulthood. Primary EBV infection in adolescents causes infectious mononucleosis. EBV infection is associated with various diseases, neoplasms and hematological disorders. Recently, we reported that EBV can infect rabbits by intravenous, intranasal and/or peroral inoculation, which caused primary EBV infection in rabbits with heterogeneous host reactions. Some rabbits showed chronic and lifelong EBV infection with hemophagocytosis. In this study, to reveal detailed mechanisms in rabbit EBV infection, an in vitro investigation was performed. We elucidated that: (1) EBV can infect rabbit peripheral blood mononuclear cells and splenic lymphocytes in vitro, because EBV gene expressions were confirmed. (2) It is highly likely that the B cell is the main target cell of rabbit EBV infection and is immortalized similar to humans. (3) CD8+ T cells increased in the rabbit in vivo model after EBV inoculation, whereas an increase of B cells occurred after their transient decrease. These data suggest that EBV-infected B cells were proliferated, while CD8+ T cells increased to recognize and kill them. This system may explain the paths of rabbit EBV infection and host reaction, simulating human EBV infection. In vitro studies will be helpful to reveal the pathogenesis of rabbit EBV infection and EBV-associated diseases. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]