In vitro replicative potential of an HIV-1/MO intergroup recombinant virus compared to HIV-1/M and HIV-1/O parental viruses

Abstract

Genetic recombination is one of the major evolution processes of HIV-1. Despite their great genetic divergence, HIV-1 groups M and O can generate HIV-1/MO intergroup recombinants. The current description of 20 HIV-1/MO unique recombinant forms suggests a possible benefit of the recombination. The aim of this work was to study in vitro the replicative potential of HIV-1/MO recombinant forms. This analysis was based on a simple recombination pattern, [O_gag/pol-M_env], harboring a breakpoint in Vpr. A chimeric infectious molecular clone, pOM-TB-2016 was synthesized from HIV-1/M subtype B and HIV-1/O subgroup T and recombinant viruses were obtained by transfection/co-culture. To compare the replicative potential of these viruses, two markers were monitored in culture supernatants: Reverse Transcriptase (RT) activity and P24 antigen concentration. The results showed a superiority of the group M parental virus compared to group O for both markers. In contrast, for the recombinant virus, RT activity data did not overlap with the concentration of P24 antigen, suggesting a hybrid behavior of the recombinant, in terms of enzyme activity and P24 production. These results highlighted many hypotheses about the impact of recombination on replicative potential and demonstrated again the significant plasticity of HIV genomes and their infinite possibility of evolution.

Figure 1

HYPERLINK "sps:id::fig1||locator::gr1||MediaObject::0"Representation of the HIV-1 intergroup M and O recombinant genomes. Two recombination patterns were designed, with a breakpoint in the vpr gene: [Mgag/pol-Oenv] pattern, in (a) and [Ogag/pol-Menv] pattern, in (b). The location of the breakpoints is indicated relative to the HIV-1/M HxB2 reference strain (GenBank accession number K03455).

Figure 2

Profile of the chimeric infectious molecular clone pOM-TB-2016. The genome portions from the parental infectious molecular clones pRBF206 (HIV-1/O) and p89.6 (HIV-1/M) are shown in blue and red, respectively. The vector pET-28b(+) is shown in green. The breakpoint, in purple, corresponds to the restriction site of the AvrII enzyme.

Figure 3

Mean kinetics of RT activity and P24 antigen concentration of parental and recombinant strains. (a) Representation of the kinetics of the mean of RT activity, in Log₁₀ pg/mL of the three triplicates, over time in days, for the parental strains HIV-1/M (in red) and HIV-1/O (in blue) and the recombinant strain HIV-1/OM (in orange). (b) Representation of the kinetics of the mean of P24 Ag concentration, in Log₁₀ pg/mL of the three triplicates, over time in days, for the parental strains HIV-1/M (in red) and HIV-1/O (in blue) and the recombinant strain HIV-1/OM (in orange).

Figure 4

General principle of the production of HIV-1/OM recombinant viruses from a CIMC. The capacity of CIMCs to produce the corresponding recombinant strains was evaluated using a protocol based on the transfection of HEK293T cells (for the production of viruses) followed by a co-culture step with the Jurkat cell line (for the viral amplification).