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SIVagm: genetic and biological features associated with replication
Michaela C Müller1, Françoise Barré-Sinoussi
1Unité de Biologie des Rétrovirus, Institut Pasteur, Paris, France. mmuller@pasteur.fr
Frontiers in Bioscience : a Journal and Virtual Library
|September 6, 2003
Summary
African green monkeys (AGMs) naturally host simian immunodeficiency virus (SIVagm) without developing AIDS. This study explores SIVagm's cell entry, replication, and regulatory proteins, revealing conserved functions with HIV-1 but distinct host-pathogen interactions that prevent disease.
Area of Science:
- Virology
- Immunology
- Primatology
Background:
- African green monkeys (AGMs) are natural hosts for distinct SIVagm subtypes and remain asymptomatic throughout life.
- SIVagm utilizes AGM CD4 and chemokine receptors (CCR5, Bonzo, Bob) for cell entry, indicating co-evolution with their hosts.
- AGM CD4 and CCR5 show molecular and functional evidence of co-evolution with SIVagm.
Purpose of the Study:
- To investigate the molecular and functional aspects of SIVagm infection in AGMs.
- To understand the mechanisms behind the lack of AIDS progression in naturally SIVagm-infected monkeys.
- To compare SIVagm's viral proteins and replication strategies with HIV-1.
Main Methods:
- Molecular and functional analyses of AGM CD4 and CCR5.
- Analysis of SIVagm regulatory proteins (Tat, Vif, Vpr, Nef).
- Quantification of plasma viral RNA and lymph node viral load in naturally infected AGMs.
Main Results:
- SIVagm replicates efficiently in vitro in PBMC and macrophages, causing cytopathic effects.
- SIVagm regulatory proteins (Tat, Vif, Vpr, Nef) show conserved functions with HIV-1, despite low amino acid identities.
- Naturally infected AGMs exhibit a wide range of viral loads, but low lymph node viral loads correlate with lack of immunopathology.
Conclusions:
- SIVagm and AGM host factors have co-evolved, contributing to asymptomatic infection.
- Conserved functions of SIVagm regulatory proteins highlight similarities and differences with HIV-1.
- Low viral load in peripheral lymph nodes is associated with the absence of AIDS progression in AGMs, warranting further investigation into host-specific protective mechanisms.