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An in vitro assay for acute pathogenicity of immunodeficiency viruses
M T Dittmar1, S Wagener, P Fultz
1Dept. of Medical Biotechnology, Paul-Ehrlich-Institute, Langen, Germany.
Abstract:
As a model for AIDS, experimental infections of old-world monkeys with various simian immunodeficiency viruses (SIV) are frequently carried out to study mechanisms of pathogenicity. For example, SIVsmmPBj14 was isolated from a pig-tailed macaque (Macaca nemestrina) suffering from acute viral disease. The molecular virus clone SIVsmmPBj1.9, which displays close genetic homology to other related SIVs, was shown to induce an acute viral disease in vivo after infection of pig-tailed and rhesus macaques. The acute pathogenicity of SIVsmmPBj1.9 was correlated with its unique ability to replicate in non-stimulated peripheral blood mononuclear cells from pig-tailed macaques. We have exploited this in vitro assay to resolve putative pathogenic genetic determinants of another SIV, namelySIVagm3, isolated from African green monkeys (Cercopithecus aethiops). Hybrid viruses encompassing subgenomic regions of SVsmmPBj1.9 in place of comparable regions of molecular virus clone SIVagm3mc were constructed and tested for their ability to replicate in non-stimulated PBMC from pig-tailed macaques and African green monkeys. Only those hybrid viruses comprising the U3 region of the viral LTR of SIVsmmPBj1.9 replicated in non-stimulated peripheral blood mononuclear cells. This in vitro assay will be used to determine the potential of SIV and of hybrid viruses between different SIVs to induce acute viral disease in vivo. It will help to avoid excessive experimental infections of monkeys with respective hybrid viruses for determining genetic determinants of acute pathogenicity of immunodeficiency viruses.
Insights
Researchers identified a key viral genetic determinant for simian immunodeficiency virus (SIV) pathogenicity. The U3 region of the viral LTR was found to be crucial for SIV replication in non-stimulated cells, aiding in predicting disease potential.
Area of Science:
- Virology
- Immunodeficiency Viruses
- Pathogenesis Research
Background:
- Simian immunodeficiency viruses (SIVs) are utilized as models to study acquired immunodeficiency syndrome (AIDS) pathogenesis.
- SIVsmmPBj1.9 induces acute disease in macaques, linked to its replication in non-stimulated peripheral blood mononuclear cells (PBMCs).
- Identifying genetic determinants of SIV pathogenicity is crucial for understanding viral disease mechanisms.
Purpose of the Study:
- To pinpoint the genetic determinants responsible for the acute pathogenicity of SIVagm3.
- To utilize an in vitro assay for predicting SIV pathogenicity and reducing animal experimentation.
- To investigate the role of specific SIV genetic regions in viral replication and disease induction.
Main Methods:
- Construction of hybrid viruses by exchanging subgenomic regions between SIVsmmPBj1.9 and SIVagm3.
- Testing the replication ability of hybrid viruses in non-stimulated PBMCs from pig-tailed macaques and African green monkeys.
- Correlation of viral replication in vitro with potential for inducing acute viral disease in vivo.
Main Results:
- Only hybrid viruses containing the U3 region of the SIVsmmPBj1.9 viral LTR (Long Terminal Repeat) replicated in non-stimulated PBMCs.
- This finding suggests the U3 region is a critical determinant for SIV replication in non-stimulated cells.
- The in vitro assay effectively predicted the replication capacity linked to pathogenicity.
Conclusions:
- The U3 region of the viral LTR is a key determinant for SIV replication in non-stimulated PBMCs.
- This in vitro assay serves as a valuable tool for predicting the pathogenic potential of SIVs and hybrid viruses.
- The assay can help minimize in vivo monkey infections when studying SIV pathogenicity determinants.