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Mitogen induction of murine C-type viruses. IV. Effects of lipoprotein E. coli, pokeweed mitogen and dextran sulphate
Abstract:
Lipoprotein E. coli, a B-cell mitogen, is identified as a new agent inducing the release of endogenous C-type virus from mouse spleen cells. Like lipopolysaccharide, a previously identified inducer, this compound has a synergistic effect with 5-bromo-2'-deoxyuridine. Induced virus has the characteristic density as well as morphology of C-type viruses. Budding viruses are detected on cultured BALB/c cells by electron microscopy 2 to 4 days following culturing in the presence of lipoprotein. Pokeweed mitogen, a compound mitogenic for T- and B-cells was negative when tested for virus induction, both alone and in combination with 5-bromo-2'-deoxyuridine. Dextran sulphate, another B-cell mitogen, was negative for induction as well. However, when, combined with lipopolysaccharide, it enhanced the virus release induced by this mitogen. In contrast, no additive effects were observed either by combining dextran sulphate with other virus amplifying mitogens or by combinations of mitogens which both have virus-inducing ability. This finding is discussed with respect to B-cell differentiation.
Insights
Lipoprotein E. coli, a B-cell mitogen, induces endogenous C-type virus release from mouse spleen cells. This effect is enhanced by 5-bromo-2'-deoxyuridine, suggesting new virus induction pathways.
Area of Science:
- Immunology
- Virology
- Cell Biology
Background:
- Endogenous C-type viruses can be released from cells by specific agents.
- Lipopolysaccharide (LPS) is a known inducer of C-type virus release.
- Understanding agents that trigger virus release is crucial for studying viral latency and pathogenesis.
Purpose of the Study:
- To identify new agents capable of inducing endogenous C-type virus release from mouse spleen cells.
- To investigate the synergistic effects of these agents with 5-bromo-2"-deoxyuridine (BrdU).
- To explore the role of B-cell mitogens in endogenous retrovirus induction.
Main Methods:
- Treatment of mouse spleen cells with various mitogens, including Lipoprotein E. coli, pokeweed mitogen, and dextran sulfate.
- Co-incubation with 5-bromo-2"-deoxyuridine (BrdU) to assess synergistic effects.
- Electron microscopy to detect and characterize budding C-type viruses.
- Analysis of virus release in response to different mitogen combinations.
Main Results:
- Lipoprotein E. coli was identified as a novel inducer of endogenous C-type virus release.
- Lipoprotein E. coli exhibited a synergistic effect with BrdU in virus induction.
- Budding C-type viruses were observed in cultured BALB/c cells treated with lipoprotein.
- Pokeweed mitogen and dextran sulfate did not induce virus release independently.
- Dextran sulfate enhanced LPS-induced virus release, but no additive effects were seen with other combinations.
Conclusions:
- Lipoprotein E. coli is a potent inducer of endogenous C-type virus release, acting synergistically with BrdU.
- The findings suggest a link between B-cell activation and endogenous retrovirus induction.
- Further research into B-cell differentiation may elucidate mechanisms of virus release.