Myeloproliferative disorder of rats induced by myeloproliferative sarcoma virus.

The pathogenesis of myeloproliferative disorder remains unknown, but there have been some experiments on murine myeloproliferative sarcoma induced by certain viruses. Myeloproliferative sarcoma virus which is well known among such viruses, causes myeloproliferative disorder in mice and today's work will reveal tumorigenicity of this virus in rats. Two groups of Jar-2 rats (31 young rats and 28 newborn rats) were prepared and each rat was injected intravenously with one shot of myeloproliferative sarcoma virus (MPSV) with the helper Friend virus (F-MuLV). Only one rat of the young rat group developed erythroleukemia, whereas 14 rats of the newborn group developed myeloproliferative disorder in which trilineages of hematopoietic cells showed marked proliferation; 8 rats developed erythroleukemia and other 3 rats developed acute myelo blastic leukemia. In addition, 15 rats of the newborn group with these hematological disorders also showed angiosarcoma of the central nervous system, mainly of the cere bellum, and 2 of them had the same angiosarcoma in the spleen. The myeloproliferative sarcoma virus might be useful as a new tool for studies of myeloproliferative disorders, not only in mice but also in rats. Introduction The myeloproliferative sarcoma virus (MPSV) is a member of the Moloney murine sarcoma virus (Mo-MuSV) family of replication-defective RNA tumor viruses derived by passage of Mo-MuSV in adult mice.1 A number of studies with mice in vivo and 糸山進次,林 祥剛 Reprint requests to: Dr. Shinji Itoyama, Department of Pathology, Saitama Medical Center, Saitama Medical School, 38 Moro Hongo, Moroyamamachi, Irumagun, Saitama 350-04, Japan