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Further studies of macrophages in relationship to avirulent Semliki Forest virus infections
Abstract:
The amount of virus in macrophages from normal mice infected in vivo and in vitro with avirulent Semliki Forest Virus A7(74)C1 and virulent L10/C1 has been compared to that in macrophages infected similarly from mice given Myocrisin (colloidal gold) before inoculation. Very high titres of virus were found in all macrophages which had been "blockaded" with Myocrisin up to 10(8.5)/ICLD50/ml with the avirulent strain and up to 10(7.2)/ICLD50/ml with the virulent strain. "Blockade" of the macrophages in this way made the normally avirulent strain virulent. The possible reasons for this are discussed.
Insights
Myocrisin (colloidal gold) blockade of macrophages increased Semliki Forest Virus titres, transforming an avirulent strain into a virulent one. This study investigates the impact of macrophage blockade on viral load and virulence.
Area of Science:
- Virology
- Immunology
- Cell Biology
Background:
- Macrophages play a crucial role in the innate immune response to viral infections.
- Myocrisin (colloidal gold) is known to affect macrophage function.
- Semliki Forest Virus (SFV) exists in both virulent and avirulent forms.
Purpose of the Study:
- To compare viral loads in macrophages from normal mice versus Myocrisin-treated mice.
- To assess the effect of Myocrisin-induced macrophage blockade on SFV virulence.
- To investigate the relationship between macrophage function and viral replication.
Main Methods:
- In vivo and in vitro infection of mouse macrophages with Semliki Forest Virus strains.
- Administration of Myocrisin (colloidal gold) to mice prior to viral inoculation.
- Quantification of viral titres in macrophages using ICLD50/ml.
Main Results:
- Myocrisin blockade resulted in significantly higher viral titres in macrophages for both avirulent (up to 10^8.5/ICLD50/ml) and virulent (up to 10^7.2/ICLD50/ml) SFV strains.
- The normally avirulent SFV strain (A7(74)C1) exhibited increased virulence after macrophages were blockaded with Myocrisin.
- Macrophage blockade enhanced viral replication and altered viral pathogenicity.
Conclusions:
- Myocrisin-mediated macrophage blockade dramatically increases Semliki Forest Virus replication.
- Macrophage blockade can potentiate normally avirulent viral strains, rendering them virulent.
- These findings highlight the critical role of macrophage phagocytic activity in controlling viral infections and virulence.