Inhibition of HIV-1 Integration in Ex Vivo-Infected CD4 T Cells from Elite Controllers

Infectious Disease Division, Massachusetts General Hospital, Boston, MA 02114. .
Journal of Virology (Impact Factor: 4.44). 09/2011; 85(18):9646-50. DOI: 10.1128/JVI.05327-11
Source: PubMed


Elite controllers spontaneously maintain undetectable levels of HIV-1 replication for reasons that remain unclear. Here, we show that in elite controllers, direct ex vivo infection of purified CD4 T cells without prior in vitro activation results in disproportionately low levels of integrated HIV-1 DNA relative to the quantity of reverse transcripts, while the levels of two-long terminal repeat (2-LTR) circles were excessively elevated relative to those of integrated HIV-1 DNA. This indicates that chromosomal HIV-1 integration is inhibited in ex vivo-infected CD4 T cells from elite controllers. This defect in HIV-1 integration was unrelated to p21, a host protein that can restrict early HIV-1 replication steps, and was not visible following infection of in vitro-activated CD4 T cells from elite controllers. These data contribute to increasing evidence that intrinsic inhibition of specific HIV-1 replication steps plays an important role in the ability of elite controllers to maintain undetectable viral loads.

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Available from: Xu G. Yu, Jan 15, 2014
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    • "HIV-1 infected controllers maintain durable viral suppression without anti-retroviral therapy (ART) and have generally been defined as either having undetectable HIV-1 RNA levels using conventional assays (elite controllers) or having low but detectable levels of viral replication below 2000 copies viral RNA/ml (viremic controllers) [1], [2], [3], [4], [5], [6]. Although mechanisms of elite control have been widely studied [7], [8], [9], [10], [11], [12], [13], the immunological factor(s) associated with host control in presence of low but detectable viral replication in viremic controllers remains of considerable interest. "
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    ABSTRACT: HIV-1 infected viremic controllers maintain durable viral suppression below 2000 copies viral RNA/ml without anti-retroviral therapy (ART), and the immunological factor(s) associated with host control in presence of low but detectable viral replication are of considerable interest. Here, we utilized a multivariable analysis to identify which innate and adaptive immune parameters best correlated with viral control utilizing a cohort of viremic controllers (median 704 viral RNA/ml) and non-controllers (median 21,932 viral RNA/ml) that were matched for similar CD4+ T cell counts in the absence of ART. We observed that HIV-1 Gag-specific CD8+ T cell responses were preferentially targeted over Pol-specific responses in viremic controllers (p = 0.0137), while Pol-specific responses were positively associated with viral load (rho = 0.7753, p = 0.0001, n = 23). Viremic controllers exhibited significantly higher NK and plasmacytoid dendritic cells (pDC) frequency as well as retained expression of the NK CD16 receptor and strong target cell-induced NK cell IFN-gamma production compared to non-controllers (p<0.05). Despite differences in innate and adaptive immune function however, both viremic controllers (p<0.05) and non-controller subjects (p<0.001) exhibited significantly increased CD8+ T cell activation and spontaneous NK cell degranulation compared to uninfected donors. Overall, we identified that a combination of innate (pDC frequency) and adaptive (Pol-specific CD8+ T cell responses) immune parameters best predicted viral load (R2 = 0.5864, p = 0.0021, n = 17) by a multivariable analysis. Together, this data indicates that preferential Gag-specific over Pol-specific CD8+ T cell responses along with a retention of functional innate subsets best predict host control over viral replication in HIV-1 infected viremic controllers compared to chronically-infected non-controllers.
    PLoS ONE 07/2014; 9(7):e103209. DOI:10.1371/journal.pone.0103209 · 3.23 Impact Factor
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    • "Cell-intrinsic antiviral effects have also been noted previously in some studies of cells from controllers in vivo [4] and ex vivo [3], [11], [12]. Decreased RT and integration of HIV-1 were seen in resting CD4+ T cells from controllers relative to those from uninfected subjects after ex vivo infection with replication-competent, Vif-positive laboratory strains of HIV-1 without spinoculation or activation [3]. "
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    ABSTRACT: Immunodeficiency does not progress for prolonged periods in some HLA B57- and/or B27-positive subjects with human immunodeficiency virus type 1 (HIV) infection, even in the absence of antiretroviral therapy (ART). These "controllers" have fewer HIV provirus-containing peripheral blood mononuclear cells than "non-controller" subjects, but lymphocytes that harbor latent proviruses were not specifically examined in studies to date. Provirus levels in resting memory cells that can serve as latent reservoirs of HIV in blood were compared here between controllers and ART-suppressed non-controllers. APOBEC3G (A3G), a cellular factor that blocks provirus formation at multiple steps if not antagonized by HIV virion infectivity factor (Vif), was also studied. HLA-linked HIV control was associated with less provirus and more A3G protein in resting CD4+ T central memory (Tcm) and effector memory (Tem) lymphocytes (provirus: p = 0.01 for Tcm and p = 0.02 for Tem; A3G: p = 0.02 for Tcm and p = 0.02 for Tem). Resting memory T cells with the highest A3G protein levels (>0.5 RLU per unit of actin) had the lowest levels of provirus (<1,000 copies of DNA per million cells) in vivo (p = 0.03, Fisher's exact test). Using two different experimental approaches, Vif-positive viruses with more A3G were found to have decreased virion infectivity ex vivo. These results raise the hypothesis that HIV control is associated with increased cellular A3G that may be packaged into Vif-positive virions to add that mode of inhibition of provirus formation to previously described adaptive immune mechanisms for HIV control.
    PLoS ONE 10/2013; 8(10):e76002. DOI:10.1371/journal.pone.0076002 · 3.23 Impact Factor
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    • "Consistent with this finding, integrated HIV DNA was more efficiently cleared in our coculture assays than 2-LTR circles suggesting CTL may explain the unique DNA profile in EC. It remains possible that other mechanisms besides CTL activity contribute to this DNA profile, such as a block to integration as recently proposed [35]. However, in our system we find integration occurs with similar efficiency in EC and normal donors [17]. "
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    ABSTRACT: Resting CD4+T cells infected with HIV persist in the presence of suppressive anti-viral therapy (ART) and are barriers to a cure. One potential curative approach, therapeutic vaccination, is fueled by recognition of the ability of a subset of elite controllers (EC) to control virus without therapy due to robust anti-HIV immune responses. Controllers have low levels of integrated HIV DNA and low levels of replication competent virus, suggesting a small reservoir. As our recent data indicates some reservoir cells can produce HIV proteins (termed GPR cells for Gag-positive reservoir cells), we hypothesized that a fraction of HIV-expressing resting CD4+T cells could be efficiently targeted and cleared in individuals who control HIV via anti-HIV cytotoxic T lymphocytes (CTL). To test this we examined if superinfected resting CD4+T cells from EC express HIV Gag without producing infectious virus and the susceptibility of these cells to CTL. We found that resting CD4+T cells expressed HIV Gag and were cleared by autologous CD8+T cells from EC. Importantly, we found the extent of CTL clearance in our in vitro assay correlates with in vivo reservoir size and that a population of Gag expressing resting CD4+T cells exists in vivo in patients well controlled on therapy.
    PLoS ONE 08/2013; 8(8):e71879. DOI:10.1371/journal.pone.0071879 · 3.23 Impact Factor
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