Malignant lymphomas, which were usually of T-cell type, were induced in 10 of 13 (77%) male rabbits (Japanese white, 8/10; New Zealand white, 2/3) inoculated i.v. with HTLV-II-transformed simian (Cynomolgus) leukocyte cell line (Si-IIA) cells. Of 7 rabbits injected with cell-free pellets from Si-IIA cultures, 5 also developed malignant lymphoma (15-28 days). Lymphoma development was completely inhibited by inactivation of cell-free pellets from Si-IIA culture with ethyl ether and was almost suppressed by neutralization of the cell-free pellets with anti-Si-IIA sera. Herpesvirus particles were discovered very rarely in Si-IIA cells, in addition to C-type virus particles, by electron microscopy. Si-IIA cells were positive for Epstein-Barr-virus (EBV)-associated nuclear antigen (EBNA) by immunofluorescence (IF) test. Antibody response to viral capsid antigen of EBV was also detected in sera from rabbits inoculated with Si-IIA. EBV-encoded RNA-1 (EBER-1) was demonstrated in Si-IIA, the tumor tissues and all rabbit tumor cell lines by in situ hybridization. EBV DNA was also detected in Si-IIA and rabbit lymphoma cell lines by polymerase chain reaction (PCR) and Southern blotting. However, EBV DNA was amplified only by some primers complementary to human EBV sequence (B95-8), but not by other primers. Integration of HTLV-II provirus genome could not be detected in Si-IIA-induced rabbit tumor cells. Moreover, no lymphoma was induced by inoculation of HTLV-IIC and MOT (other HTLV-II-producing human cell lines), B95-8(EBV-producing cell line) or TALL-1 and peripheral leukocytes from normal Cynomolgus (controls). Neither Herpesvirus saimiri nor H. ateles (simian oncogenic viruses) were detected in Si-IIA cells by IF test. These data suggest that the high rate of lymphoma induction in rabbits may not be caused by HTLV-II, human EBV (B95-8) or well-known simian oncogenic viruses, but by EBV-related herpesvirus derived from Si-IIA cells or HTLV-IIA cells, with which Si-IIA was established. The availability of this animal model promises to clarify the role of EBV in human lymphoma and provides a means of studying prophylactic and therapeutic regimens.
Lymphoma induction in rabbits by an unknown factor derived from an HTLV‐II‐producing simian (Cynomolgus) leukocyte cell line (Si‐IIA) is reported. Thirteen of 17 male Japanese white rabbits (76%) inoculated intravenously with Si‐IIA cells developed malignant lymphoma including Hodgkin‐like lymphoma between 62 and 167 days after inoculation. Historically, there was extensive diffuse or nodular infiltration of either large cell type or mixed type lymphoma cells in many organs, frequently involving the spleen, liver, lymph nodes and kidneys, and less frequently the thymus, bone marrow, lungs, heart, skin and gastrointestinal tract. Hodgkin‐like lymphoma was also observed in two rabbits. Chromosomal analysis of five cell lines established from tumor‐bearing rabbits revealed the male rabbit karyotype. The immunophenotype of these tumor cells was usually T‐cell (CD5+or, r RT1+, RT2+or‐, CD45+, CD4−, RABELA− and MHC class II‐DQ+) except for Hodgkin‐like lymphoma cells which expressed only CD45. However, integration of the HTLV‐II provirus genome could not be demonstrated in the tumor tissues or any of the rabbit cell lines by polymerase chain reaction or Southern blot analysis. Moreover, no lymphoma was induced by inoculation of HTLV‐IIC, MOT (other HTLV‐II‐producing human cell lines) or TALL‐1 (control). Two of four rabbits injected with cell‐free pellets from Si‐IIA cultures died of malignant lymphoma (15‐20 days). Five irradiated rabbit cell lines were inoculated but only one (Ra‐SLN) induced lymphoma in 1 of 3 rabbits at 27 days. Neither Herpesvirus saimiri nor Herpesvirus ateles (simian oncogenic viruses) was detected in Si‐IIA cells by immunofluorescence testing. These data suggest that the high rate of lymphoma induction in rabbits may be caused not by only HTLV‐II or well known simian oncogenic viruses, but rather by an unknown passenger agent derived from Si‐IIA or HTLV‐IIA, with which Si‐IIA was established.
A case of inflammatory pseudotumor of the urinary bladder in a 47 year old Japanese male patient is presented. Inflammatory pseudotumor of the urinary bladder is a benign but rare proliferative lesion of the submucosal stroma, easily mistaken for a malignant neoplasm. Based on the clinical diagnosis of bladder cancer by cystoscopy and magnetic resonance imaging (MRI), urologists started chemotherapy before results of the histological report were available which described inflammatory pseudotumor on the biopsy. Biopsied materials showed marked proliferation of irregularly bundled spindle cells, varied in size and shape and separated in severe loose myxoid stroma with moderate infiltration of the inflammatory cells and capillary proliferations. At a glance, these findings resemble the sarcomatous pattern. However neither severe nuclear atypism nor atypical mitoses were present. Immunohistochemically, these spindle cells, which were positive for vimentin and alpha-smooth muscle actin, showed a diffuse aberrant expression of cytokeratin. Some of them were positive for phosphotungstic acid hematoxylin. Electron microscopy revealed only the fibroblasts. No recurrence has been observed for 10 months. These findings indicate that inflammatory pseudotumor is a benign mesenchymal lesion that must be discriminated from true sarcoma to avoid subjecting the patient to unnecessary therapy. Only careful histological examination can enable a successful diagnosis.
Malignant lymphoma (ML) was induced in eight of nine rabbits inoculated by oral spray of the cell-free pellets from Si-IIA culture (HTLV-II-transformed leukocyte cell line of the Cynomolgus-producing Epstein-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 with 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 malignant 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.
Epstein-Barr virus-associated hemophagocytic syndrome (EBV-AHS) is often associated with fatal infectious mononucleosis or T-cell lymphoproliferative diseases (LPD). To elucidate the true nature of fatal LPD observed in Herpesvirus papio (HVP)-induced rabbit hemophagocytosis, reactive or neoplastic, we analyzed sequential development of HVP-induced rabbit LPD and their cell lines. All of the seven Japanese White rabbits inoculated intravenously with HVP died of fatal LPD 18 to 27 days after inoculation. LPD was also accompanied by hemophagocytic syndrome (HPS) in five of these seven rabbits. Sequential autopsy revealed splenomegaly and swollen lymph nodes, often accompanied by bleeding, which developed in the last week. Atypical lymphoid cells infiltrated many organs with a "starry sky" pattern, frequently involving the spleen, lymph nodes, and liver. HVP-small RNA-1 expression in these lymphoid cells was clearly demonstrated by a newly developed in situ hybridization (ISH) system. HVP-ISH of immunomagnetically purified lymphoid cells from spleen or lymph nodes revealed HVP-EBER1+ cells in each CD4+, CD8+, or CD79a+ fraction. Hemophagocytic histiocytosis was observed in the lymph nodes, spleen, bone marrow, and thymus. HVP-DNA was detected in the tissues and peripheral blood from the infected rabbits by PCR or Southern blot analysis. Clonality analysis of HVP-induced LPD by Southern blotting with TCR gene probe revealed polyclonal bands, suggesting polyclonal proliferation. Six IL-2-dependent rabbit T-cell lines were established from transplanted scid mouse tumors from LPD. These showed latency type I/II HVP infection and had normal karyotypes except for one line, and three of them showed tumorigenicity in nude mice. These data suggest that HVP-induced fatal LPD in rabbits is reactive polyclonally in nature.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.