Transplantable myeloproliferative disease induced in mice by an interleukin 6 retrovirus

• Published in: The Journal of experimental medicine Vol. 176; no. 4; pp. 1149 - 1163
• Main Authors: HAWLEY, R. G, FONG, A. Z. C, BURNS, B. F, HAWLEY, T. S
• Format: Journal Article
• Language: English
• Published: New York, NY Rockefeller University Press 01.10.1992; The Rockefeller University Press
• Subjects: Animals; Biological and medical sciences; Blood Proteins - isolation & purification; Bone Marrow Transplantation - methods; Cell Line; Cells, Cultured; DNA, Viral - genetics; DNA, Viral - isolation & purification; Female; Genetic Vectors; Hematologic and hematopoietic diseases; Hematopoietic Stem Cells - pathology; Interleukin-6 - analysis; Interleukin-6 - genetics; Leukocyte Count; Medical sciences; Mice; Mice, Inbred BALB C; murine leukemia virus; Myeloproliferative Disorders - blood; Myeloproliferative Disorders - microbiology; Myeloproliferative Disorders - pathology; Other diseases. Hematologic involvement in other diseases; Proviruses - genetics; Retroviridae - genetics; Retroviridae - pathogenicity; Time Factors; Transfection; Virus Integration; Animal model; Pathogenesis; Recombinant virus; Rodentia; Hemopathy; Adoptive transfer; Interleukin 6; Myeloproliferative syndrome; Vertebrata; Mammalia; Gene; Mouse; Bone marrow; Infected cell
• ISSN: 0022-1007; 1540-9538
• DOI: 10.1084/jem.176.4.1149

Lethally irradiated mice transplanted with bone marrow cells infected with a novel recombinant retrovirus (murine stem cell virus-interleukin 6 [MSCV-IL-6]) bearing a mouse IL-6 gene developed a fatal myeloproliferative disease within 4 wk of engraftment. The hematologic manifestations of the syndrome included elevated peripheral leukocyte counts (up to 430 x 10(3) cells/mm3) with a predominance of neutrophilic granulocytes, microcytic anemia, and thrombocytosis or thrombocytopenia. The mice showed extensive neutrophil infiltration of the lungs, liver, and occasionally lymph nodes, plus splenomegaly resulting from enhanced splenic myelopoiesis (30-60-fold increase in progenitor numbers). Despite the chronic stimulation of neutrophil excess by IL-6, bone marrow from affected mice was capable of repopulating the hematopoietic tissues (bone marrow and spleen) of lethally irradiated hosts during repeated serial transplantation. In the longest documented case, the progeny of a single MSCV-IL-6-marked cell transferred the myeloproliferative disease to two secondary, four tertiary, and two quaternary recipients (the clone endured for a total of 72 wk). These results, demonstrating considerable proliferative longevity of the IL-6-producing cells, support an in vivo role of IL-6 in the maintenance of hematopoietic precursors. Dysregulated IL-6 production also had significant systemic effects. The mice displayed increased mesangial cell proliferation in the kidney, frequent liver abnormalities, and marked alterations in plasma protein levels. Unlike previous studies where constitutive expression of exogenous IL-6 genes resulted in lymphoproliferative disorders characterized by massive plasmacytosis, minimal plasma cell expansion occurred in the MSCV-IL-6 mice during the observation period. Potential explanations for the differences in disease phenotypes observed in the present and previous studies are different cell types expressing the exogenous IL-6 genes, higher sustained circulating levels of IL-6 achieved using the MSCV-IL-6 retroviral delivery system, and/or the premature death (3-15 wk after transplantation) of the MSCV-IL-6 mice before the onset of plasmacytosis. This animal model should prove useful for further investigation of the function of IL-6 in normal and abnormal hematopoiesis and in inflammatory responses.