Effects of simian betaretrovirus serotype 1 (SRV1) infection on the differentiation of hematopoietic progenitor cells (CD34+) derived from bone marrow of rhesus macaques (Macaca mulatta).
ABSTRACT Peripheral blood cytopenias, particularly persistent anemia and neutropenia, are commonly associated with simian betaretrovirus infection of Asian monkeys of the genus Macaca. The pathogenetic mechanisms underlying these hematologic abnormalities are not well understood. The current study investigated the in vitro tropism of simian betaretrovirus (SRV) for both hematopoietic progenitor (CD34(+)) and stromal cells obtained from rhesus macaque bone marrow and assessed the effects of infection on hematopoietic progenitor cell differentiation in vitro. After in vitro exposure, SRV proviral DNA could be demonstrated by real-time PCR in cells and the reverse transcriptase assay in supernatants from SRV-exposed progenitor-associated stroma, but not in differentiated colonies derived from SRV-exposed progenitors. Furthermore, in vitro exposure involving cell-cell contact of uninfected CD34(+) progenitor cells with SRV-infected stromal cells resulted in a statistically significant reduction in granulocyte-macrophage colony formation in absence of detectable SRV-infection of progenitor cells. Reduction in colony formation occurred in a 'dose-dependent' fashion with increasing contact time. No effects on erythroid lineages and RBC differentiation were noted. Our results suggest that hematologic abnormalities observed during SRV disease (natural or experimental) of rhesus macaques may not result from direct effects of viral infection of progenitor cell populations, but rather be (at least in part) a consequence of SRV infection of supportive bone marrow stroma with secondary effects on differentiation of associated progenitor cells.
Article: Adenosine deaminase-complexing protein from bovine kidney. Isolation of two distinct subunits.[show abstract] [hide abstract]
ABSTRACT: We have isolated a complex of two proteins from bovine kidney that bind to adenosine deaminase immobilized on Sepharose 4B. One protein, with Mr = 110,000, comigrates on both PAGE and SDS-PAGE gels with complexing protein isolated from rabbit kidney by the method of Schrader et al. (Schrader, W.P., Harder, C. M., and Schrader, D. K. (1983) Comp. Biochem. Physiol. B Comp. Biochem. 75, 119-126). The second protein has a Mr = 70,000. Both proteins bind to the adenosine deaminase-Sepharose but not to a control resin of bovine serum albumin bound to Sepharose. Based on a comparison of partial and complete denaturation on SDS-PAGE the two proteins appear to be bound to each other. At adenosine concentrations of 0.5-1 mM the isolated complexing protein increases small subunit adenosine deaminase catalytic activity by 20-30%. There may be some inhibition of catalytic activity at low adenosine concentrations. We have designated the 110,000 Mr protein CP-I, the 70,000 Mr protein CP-II and the complex of these two CP.Journal of Biological Chemistry 05/1988; 263(11):5266-70. · 4.77 Impact Factor
Article: Simian retrovirus D serogroup 1 has a broad cellular tropism for lymphoid and nonlymphoid cells.[show abstract] [hide abstract]
ABSTRACT: Simian acquired immunodeficiency syndrome is a fatal immunosuppressive disease caused by type D retroviruses such as simian acquired immunodeficiency syndrome retrovirus type 1 (SRV-1). The disease is characterized by generalized lymphadenopathy, opportunistic infections, and lymphoid depletion with defects in both humoral and cell-mediated immunity. To understand how SRV-1 infection relates to the immune defect, we studied in vivo-infected lymphocytes from SRV-1-positive macaques with and without clinical signs of immunosuppressive disease. B and T helper/inducer and T suppressor/cytotoxic lymphocytes were purified by panning or by flow cytometry. Neutrophils were purified by dextran sedimentation, and platelets were purified by low-speed centrifugation. In vitro infection studies were also done with HUT78, H9, K562, rhesus lung fibroblast, rhesus monkey kidney, and bat lung cells. SRV-1 in lymphocytes or culture supernatants was detected by the induction of syncytia in cocultivated Raji cells and was confirmed by immunofluorescence, electron microscopy, or reverse transcriptase assay. We found that B and T helper/inducer lymphocytes were infected in all animals tested. The number of infected T suppressor/cytotoxic cells was generally lower than that of the other cell subsets, and not all animals in this subset had SRV-1 infections. All other cells exposed in vitro to SRV-1, except bat lung cells, were able to be infected. These findings show that SRV-1 has a broad cell tropism for lymphoid and nonlymphoid cell types.Journal of Virology 06/1988; 62(5):1768-73. · 5.40 Impact Factor
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ABSTRACT: The pathogenic mechanisms underlying the depressed hematopoietic functions seen in human immunodeficiency virus-infected individuals were explored in rhesus monkeys infected with the simian immunodeficiency virus of macaques (SIVmac). Bone marrow hematopoietic progenitor cell colony formation, both granulocyte/macrophage (CFU-GM) and erythrocyte (BFU-E), was shown to be decreased in number in SIVmac-infected rhesus monkeys. SIVmac was readily isolated from bone marrow cells of infected monkeys and was shown to be harbored in macrophages rather than T lymphocytes. The in vitro infection of normal bone marrow cells by SIVmac inhibited colony formation. A striking in vivo correlation between increased SIVmac load in bone marrow cells and decreased hematopoietic progenitor cell colony growth was also shown. Finally, inhibition of SIVmac replication in bone marrow macrophages resulted in increased progenitor cell colony growth from bone marrow cells. These results suggest that the infection of bone marrow macrophages by the acquired immunodeficiency syndrome (AIDS) virus may contribute to depressed bone marrow hematopoietic progenitor cell growth. Moreover, inhibition of AIDS virus replication in these macrophages might induce significant improvement in hematopoietic function.Journal of Virology 03/1990; 64(2):656-63. · 5.40 Impact Factor