Infection Of Hematopoietic Cells Research Articles

Retrovirus-Mediated Transfer and Expression of the Interleukin-3 Gene in Mouse Hematopoietic Cells Result in a Myeloproliferative Disorder

A high-titer, recombinant retroviral vector produced in psi 2 packaging cells has been used to introduce the murine interleukin-3 (IL-3) gene into mouse hematopoietic cells. Integration and expression of the IL-3 gene was observed in spleen foci from which could be derived factor-independent, continuously proliferating cell lines. Irradiated or genetically anemic W/Wv recipients of infected hematopoietic cells developed a myeloproliferative syndrome characterized by a marked elevation in leukocyte count, bone marrow hyperplasia, and enlargement of the liver and spleen. The syndrome reflected proliferation of one or more stem cell clones, the progeny of which were capable of repopulating secondary recipients. One animal developed the syndrome primarily by a paracrine mechanism. Endogenous IL-3 production caused amplification of hematopoietic cells but did not appear to alter the maturational or self-renewal potential of these cells.

Retrovirus-mediated transfer and expression of the interleukin-3 gene in mouse hematopoietic cells result in a myeloproliferative disorder.

A high-titer, recombinant retroviral vector produced in psi 2 packaging cells has been used to introduce the murine interleukin-3 (IL-3) gene into mouse hematopoietic cells. Integration and expression of the IL-3 gene was observed in spleen foci from which could be derived factor-independent, continuously proliferating cell lines. Irradiated or genetically anemic W/Wv recipients of infected hematopoietic cells developed a myeloproliferative syndrome characterized by a marked elevation in leukocyte count, bone marrow hyperplasia, and enlargement of the liver and spleen. The syndrome reflected proliferation of one or more stem cell clones, the progeny of which were capable of repopulating secondary recipients. One animal developed the syndrome primarily by a paracrine mechanism. Endogenous IL-3 production caused amplification of hematopoietic cells but did not appear to alter the maturational or self-renewal potential of these cells.

Altered stem cell (CFU-S) function following infection of hematopoietic cells with a virus carrying V-src

Long-term murine bone marrow cultures were used to support the growth and development of hematopoietic cells. After hematopoiesis was established, the cultures were infected with a recombinant murine amphotropic virus carrying the avian sarcoma virus src gene and the CFU- S kinetics were examined. The CFU-S from the src-infected cultures displayed a reduced seeding efficiency in the standard spleen colony assay. The self-renewal capacity of these CFU-S was tested by their ability to reestablish hematopoiesis when serially transplanted on irradiated bone marrow cultures and by serial passage in spleens of irradiated mice. In both tests, cells from the src-infected cultures exhibited an enhanced ability to sustain a high level of self-renewal. The other property of stem cells which may be measured is the probability of self-renewal at each cell division which dictates the distribution between stem cells and differentiated type progeny. CFU-S from the src-infected cultures had higher average probabilities of self- renewal and therefore reduced differentiation. These differences suggest that expression of src had indirectly or directly altered the normal differentiation program of the stem cells.

Altered Stem Cell (CFU-S) Function Following Infection of Hematopoietic Cells With a Virus Carrying V-src

Long-term murine bone marrow cultures were used to support the growth and development of hematopoietic cells. After hematopoiesis was established, the cultures were infected with a recombinant murine amphotropic virus carrying the avian sarcoma virus src gene and the CFU-S kinetics were examined. The CFU-S from the src-infected cultures displayed a reduced seeding efficiency in the standard spleen colony assay. The self-renewal capacity of these CFU-S was tested by their ability to reestablish hematopoiesis when serially transplanted on irradiated bone marrow cultures and by serial passage in spleens of irradiated mice. In both tests, cells from the src-infected cultures exhibited an enhanced ability to sustain a high level of self-renewal. The other property of stem cells which may be measured is the probability of self-renewal at each cell division which dictates the distribution between stem cells and differentiated type progeny. CFU-S from the src-infected cultures had higher average probabilities of self-renewal and therefore reduced differentiation. These differences suggest that expression of src had indirectly or directly altered the normal differentiation program of the stem cells.

Viral expression in two myelomonocytic cell lines obtained from long-term bone marrow culture infected with the friend polycythemia-inducing virus (FV-P)

Two subclones of monomyelocytic cell lines (317 and G-31), issued from mouse long-term bone marrow cultures infected with Friend polycythemia-inducing virus, were studied for virus release and viral protein expression. The 317 cell line permanently produced biologically active spleen focus-forming virus (SFFV) and expressed the gp52 SFFV which has been described as encoded by the SFFV genome. In contrast, the G-31 cell line was devoid of any SFFV expression although it released Friend helper leukemia virus (FMuLV). Both lines expressed a new gp70-related glycoprotein with an apparent molecular weight of 66,000. This gp66 species was metabolically unstable and was not packaged into viral particles nor released in culture medium. It was recognized by an anti-Rauscher gp70 antiserum but not by anti-MCF gp70 or anti-p15E antisera. gp66 was not found in erythroblastic Friend tumor cell lines, in fibroblasts infected with virus released by lines 317 and G-31, or in nonmyelomonocytic infected hematopoietic cells. However, it was constantly observed in cell lines with a myelomonocytic origin established in vivo and in vitro. Therefore, gp66 is a F-MuLV gp70-related product specifically linked to the myeloid lineage.