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Characterization of less pathogenic infectious molecular clones derived from acute-pathogenic SHIV-89.6p stock virus
I L Kozyrev1, K Ibuki, T Shimada
1Laboratory of Viral Pathogenesis, Graduate School of Medicine, Kyoto University, 606-8507, Japan.
Abstract:
For a better understanding of the acute pathogenicity of SHIV-89.6P stock virus, which induces prominent CD4 cell loss within a month after inoculation in monkeys, we have constructed four infectious molecular clones (cl 18, cl 64, cl 69, and cl 71). Cl 64, cl 69, and cl 71, like the parental virus, showed a high in vitro replication ability and a pathogenic-like effect (CD4 downmodulation) in a monkey CD4(+) cell line, whereas cl 18 showed a lower replication ability and could not downmodulate CD4. Cl 64, which has characteristics similar to those of the parental virus in vitro, was inoculated into four rhesus monkeys. All monkeys showed a plasma viral load similar to that of the parental virus with a peak at 2 weeks after inoculation. However, the viral load gradually decreased and the virus failed to cause an AIDS-like disease in infected monkeys, but it induced a strong antiviral antibody response. These results demonstrate the polyclonal nature of the parental SHIV-89.6P virus stock and demonstrate that cl 64, aside from its high replicability, may differ qualitatively from the parental virus.
Insights
Researchers explored the pathogenicity of the SHIV-89.6P virus by creating molecular clones. Clone 64 showed high replication but did not cause AIDS-like disease in monkeys, indicating the parental virus is polyclonal.
Area of Science:
- Virology
- Immunology
- Molecular Biology
Background:
- The Simian-Human Immunodeficiency Virus (SHIV)-89.6P stock virus is known for causing rapid CD4+ T-cell depletion in non-human primates.
- Understanding the genetic basis of SHIV pathogenicity is crucial for developing effective vaccines and therapies.
Purpose of the Study:
- To investigate the acute pathogenicity of the SHIV-89.6P stock virus.
- To characterize the in vitro and in vivo properties of infectious molecular clones derived from SHIV-89.6P.
- To determine the relationship between viral replication, CD4+ T-cell modulation, and disease progression.
Main Methods:
- Construction and characterization of four infectious molecular clones (cl 18, cl 64, cl 69, cl 71) from SHIV-89.6P.
- In vitro replication assays and CD4+ cell line studies to assess viral replication and CD4 downmodulation.
- Inoculation of rhesus monkeys with clone 64 to evaluate in vivo pathogenicity, viral load, and immune response.
Main Results:
- Clones 64, 69, and 71 exhibited high in vitro replication and CD4 downmodulation, similar to the parental virus.
- Clone 18 showed reduced replication and no CD4 downmodulation.
- Monkeys inoculated with clone 64 displayed transient viral loads similar to the parental virus but did not develop AIDS-like disease, though a strong antibody response was observed.
Conclusions:
- The SHIV-89.6P stock virus is polyclonal, with different clones possessing distinct pathogenic properties.
- Clone 64, despite high replicability, differs qualitatively from the parental virus in its ability to induce disease in vivo.
- These findings highlight the complexity of SHIV pathogenesis and the need for detailed clone characterization.