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Updated: May 11, 2026
A Restriction Enzyme Based Cloning Method to Assess the In vitro Replication Capacity of HIV-1 Subtype C Gag-MJ4 Chimeric Viruses
Published on: August 31, 2014
High level of susceptibility to human TRIM5α conferred by HIV-2 capsid sequences
Junko S Takeuchi1, Benjamin Perche, Julie Migraine
1INSERM U941, Paris 75010, France.
Background:
HIV-2, which was transmitted to humans from a distant primate species (sooty mangabey), differs remarkably from HIV-1 in its infectivity, transmissibility and pathogenicity. We have tested the possibility that a greater susceptibility of HIV-2 capsid (CA) to the human restriction factor TRIM5α (hTRIM5α) could contribute to these differences.
Results:
We constructed recombinant clones expressing CA from a variety of HIV-2 viruses in the context of HIV-1 NL4-3-luciferase. CA sequences were amplified from the plasma of HIV-2 infected patients, including 8 subtype A and 7 subtype B viruses. CA from 6 non-epidemic HIV-2 subtypes, 3 HIV-2 CRF01_AB recombinants and 4 SIVsmm viruses were also tested. Susceptibility to hTRIM5α was measured by comparing single-cycle infectivity in human target cells expressing hTRIM5α to that measured in cells in which hTRIM5α activity was inhibited by overexpression of hTRIM5γ.The insertion of HIV-2 CA sequences in the context of HIV-1 did not affect expression and maturation of the HIV-2 CA protein. The level of susceptibility hTRIM5α expressed by viruses carrying HIV-2 CA sequences was up to 9-fold higher than that of HIV-1 NL4-3 and markedly higher than a panel of primary HIV-1 CA sequences. This phenotype was found both for viruses carrying CA from primary HIV-2 sequences and viruses carrying CA from laboratory-adapted HIV-2 clones. High hTRIM5α susceptibility was found in all HIV-2 subtypes. In this series of viruses, susceptibility to hTRIM5α was not significantly affected by the presence of a proline at position 119 or by the number of prolines at positions 119, 159 or 178 in HIV-2 CA. No significant correlation was found between HIV-2 viremia and sensitivity to hTRIM5α.
Conclusions:
HIV-2 capsid sequences expressed high levels of susceptibility to hTRIM5α. This property, common to all HIV-2 sequences tested, may contribute in part to the lower replication and pathogenicity of this virus in humans.
Insights
HIV-2 capsid proteins are highly susceptible to the human TRIM5α restriction factor. This increased susceptibility may explain HIV-2's lower replication and pathogenicity compared to HIV-1 in humans.
Area of Science:
- Virology
- Immunology
- Molecular Biology
Background:
- Human Immunodeficiency Virus type 2 (HIV-2) originates from sooty mangabeys and exhibits distinct infectivity, transmissibility, and pathogenicity compared to HIV-1.
- The human TRIM5α protein acts as a restriction factor, limiting retroviral replication.
Purpose of the Study:
- To investigate whether increased susceptibility of HIV-2 capsid (CA) to human TRIM5α (hTRIM5α) contributes to the observed differences between HIV-1 and HIV-2.
- To analyze the impact of various HIV-2 capsid sequences on hTRIM5α susceptibility.
Main Methods:
- Recombinant HIV-1 NL4-3 luciferase viruses were engineered to express capsid (CA) sequences from diverse HIV-2 subtypes, CRF01_AB recombinants, and SIVsmm.
- Susceptibility to hTRIM5α was quantified by comparing single-cycle infectivity in hTRIM5α-expressing cells versus cells where hTRIM5α was inhibited by hTRIM5γ overexpression.
Main Results:
- HIV-2 CA sequences, when incorporated into an HIV-1 context, did not affect viral expression or maturation.
- Viruses containing HIV-2 CA displayed up to a 9-fold higher susceptibility to hTRIM5α compared to HIV-1 NL4-3 and primary HIV-1 CA sequences.
- This heightened hTRIM5α susceptibility was consistent across all tested HIV-2 subtypes, laboratory-adapted strains, and primary isolates, independent of specific proline residues in the CA sequence.
Conclusions:
- HIV-2 capsid sequences exhibit a significant susceptibility to the human TRIM5α restriction factor.
- This intrinsic property of HIV-2 CA may be a key factor contributing to its reduced replication rate and lower pathogenicity in the human host.
