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Persistent resistance to HIV-1 infection in CD4 T cells from exposed uninfected Vietnamese individuals is mediated by entry and post-entry blocks.

Sáez-Cirión A, Versmisse P, Truong LX, Chakrabarti LA, Carpentier W, Barré-Sinoussi F, Scott-Algara D, Pancino G - Retrovirology (2006)

Bottom Line: In two cases this resistance was associated with low CCR5 surface expression, which was itself associated with heterozygous CCR5 mutations.The restriction was not overcome by a high viral inoculum, suggesting that it was not mediated by a saturable inhibitory factor.Various constitutive mechanisms of CD4 T cell resistance to HIV-1 infection, affecting entry or post-entry steps of viral replication, are associated with resistance to HIV-1 in subjects who remain uninfected despite long-term high-risk behavior.

View Article: PubMed Central - HTML - PubMed

Affiliation: Unité de Régulation des Infections Rétrovirales, Institut Pasteur, Paris, France. asiersc@pasteur.fr

ABSTRACT

Background: We have previously reported that CD4 T cells from some exposed uninfected (EU) Vietnamese intravenous drug users are relatively resistant to HIV infection in vitro. Here, we further characterized the restriction of viral replication in CD4 T cells from five EUs and assessed its persistence in serial samples.

Results: CD4 T cells and/or PBMC sampled during a period of between 2 and 6 years were challenged with replication-competent HIV-1 and other retroviral particles pseudotyped with envelope proteins of various tropisms. CCR5 expression and function in resistant CD4 T cells was evaluated. The step at which HIV-1 replication is restricted was investigated by real-time PCR quantification of HIV-1 reverse transcripts. We identified three patterns of durable HIV-1 restriction in EU CD4 T cells. CD4 T cells from four of the five EU subjects were resistant to HIV-1 R5 infection. In two cases this resistance was associated with low CCR5 surface expression, which was itself associated with heterozygous CCR5 mutations. In the other two cases, CD4 T cells were resistant to HIV-1 R5 infection despite normal CCR5 expression and signaling function, and normal beta-chemokine secretion upon CD4 T cell activation. Instead, restriction appeared to be due to enhanced CD4 T cell sensitivity to beta-chemokines in these two subjects. In the fifth EU subject the restriction involved post-entry steps of viral replication and affected not only HIV-1 but also other lentiviruses. The restriction was not overcome by a high viral inoculum, suggesting that it was not mediated by a saturable inhibitory factor.

Conclusion: Various constitutive mechanisms of CD4 T cell resistance to HIV-1 infection, affecting entry or post-entry steps of viral replication, are associated with resistance to HIV-1 in subjects who remain uninfected despite long-term high-risk behavior.

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Pantropic restriction in CD4 T cells from subject W276 affects the replication of several retroviruses. A. Early reverse transcripts (RU5) analyzed by real-time PCR at various times after HIV-VSVG pseudotype challenge of CD4 T cells from subject W276 (open circles) and a representative control (filled triangles). B. Infection of CD4 T cells from subject W276 (open circles) and a control (filled triangles) with increasing amounts of HIV-VSVG pseudotype. Results (mean of three independent infections) are expressed as luciferase activity per second in cell lysates three days post-challenge. The control is representative of cells from three different controls. Error bars represent the standard deviation. C. Relative infection of CD4 T cells from subject W276 (white bars) by HIV-1, SIVmac and SIVagm particles pseudotyped with the VSVG fusion protein (n = 3, mean ± SD). Luciferase activity in cell lysates from a representative control (black bars) was attributed a value of 100%.
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Figure 4: Pantropic restriction in CD4 T cells from subject W276 affects the replication of several retroviruses. A. Early reverse transcripts (RU5) analyzed by real-time PCR at various times after HIV-VSVG pseudotype challenge of CD4 T cells from subject W276 (open circles) and a representative control (filled triangles). B. Infection of CD4 T cells from subject W276 (open circles) and a control (filled triangles) with increasing amounts of HIV-VSVG pseudotype. Results (mean of three independent infections) are expressed as luciferase activity per second in cell lysates three days post-challenge. The control is representative of cells from three different controls. Error bars represent the standard deviation. C. Relative infection of CD4 T cells from subject W276 (white bars) by HIV-1, SIVmac and SIVagm particles pseudotyped with the VSVG fusion protein (n = 3, mean ± SD). Luciferase activity in cell lysates from a representative control (black bars) was attributed a value of 100%.

Mentions: Previous qualitative PCR analysis of viral replication in CD4 T cells from subject W276 suggested that the restriction step occurred before integration [11], but early times post-infection were not analyzed. We therefore used single-round infection and real-time PCR to determine the precise stage at which the restriction occurred. Early reverse transcription products (R-U5) were far lower in W276 cells than in control cells, from the very first hours after infection (fig. 4A), and they increased very little during the time course of infection. Levels of PCR products corresponding to subsequent replication steps were also decreased (not shown). These results suggest that early post-entry steps of viral replication, most likely involving reverse transcription, are impaired in W276 CD4 T cells. Note that W276 CD4 T cells were readily activated by PHA (>95% of cells were CD25+ at the time of challenge) thus discarding that the restriction of HIV-1 infection was caused by a defect of the response to PHA-stimulation. In addition, HIV-1 restriction in W276 CD4 T cells was not overcome by increasing the size of the inoculum of VSV-G pseudotyped HIV-1 (fig. 4B), arguing against a role of a saturable restriction factor.


Persistent resistance to HIV-1 infection in CD4 T cells from exposed uninfected Vietnamese individuals is mediated by entry and post-entry blocks.

Sáez-Cirión A, Versmisse P, Truong LX, Chakrabarti LA, Carpentier W, Barré-Sinoussi F, Scott-Algara D, Pancino G - Retrovirology (2006)

Pantropic restriction in CD4 T cells from subject W276 affects the replication of several retroviruses. A. Early reverse transcripts (RU5) analyzed by real-time PCR at various times after HIV-VSVG pseudotype challenge of CD4 T cells from subject W276 (open circles) and a representative control (filled triangles). B. Infection of CD4 T cells from subject W276 (open circles) and a control (filled triangles) with increasing amounts of HIV-VSVG pseudotype. Results (mean of three independent infections) are expressed as luciferase activity per second in cell lysates three days post-challenge. The control is representative of cells from three different controls. Error bars represent the standard deviation. C. Relative infection of CD4 T cells from subject W276 (white bars) by HIV-1, SIVmac and SIVagm particles pseudotyped with the VSVG fusion protein (n = 3, mean ± SD). Luciferase activity in cell lysates from a representative control (black bars) was attributed a value of 100%.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1636660&req=5

Figure 4: Pantropic restriction in CD4 T cells from subject W276 affects the replication of several retroviruses. A. Early reverse transcripts (RU5) analyzed by real-time PCR at various times after HIV-VSVG pseudotype challenge of CD4 T cells from subject W276 (open circles) and a representative control (filled triangles). B. Infection of CD4 T cells from subject W276 (open circles) and a control (filled triangles) with increasing amounts of HIV-VSVG pseudotype. Results (mean of three independent infections) are expressed as luciferase activity per second in cell lysates three days post-challenge. The control is representative of cells from three different controls. Error bars represent the standard deviation. C. Relative infection of CD4 T cells from subject W276 (white bars) by HIV-1, SIVmac and SIVagm particles pseudotyped with the VSVG fusion protein (n = 3, mean ± SD). Luciferase activity in cell lysates from a representative control (black bars) was attributed a value of 100%.
Mentions: Previous qualitative PCR analysis of viral replication in CD4 T cells from subject W276 suggested that the restriction step occurred before integration [11], but early times post-infection were not analyzed. We therefore used single-round infection and real-time PCR to determine the precise stage at which the restriction occurred. Early reverse transcription products (R-U5) were far lower in W276 cells than in control cells, from the very first hours after infection (fig. 4A), and they increased very little during the time course of infection. Levels of PCR products corresponding to subsequent replication steps were also decreased (not shown). These results suggest that early post-entry steps of viral replication, most likely involving reverse transcription, are impaired in W276 CD4 T cells. Note that W276 CD4 T cells were readily activated by PHA (>95% of cells were CD25+ at the time of challenge) thus discarding that the restriction of HIV-1 infection was caused by a defect of the response to PHA-stimulation. In addition, HIV-1 restriction in W276 CD4 T cells was not overcome by increasing the size of the inoculum of VSV-G pseudotyped HIV-1 (fig. 4B), arguing against a role of a saturable restriction factor.

Bottom Line: In two cases this resistance was associated with low CCR5 surface expression, which was itself associated with heterozygous CCR5 mutations.The restriction was not overcome by a high viral inoculum, suggesting that it was not mediated by a saturable inhibitory factor.Various constitutive mechanisms of CD4 T cell resistance to HIV-1 infection, affecting entry or post-entry steps of viral replication, are associated with resistance to HIV-1 in subjects who remain uninfected despite long-term high-risk behavior.

View Article: PubMed Central - HTML - PubMed

Affiliation: Unité de Régulation des Infections Rétrovirales, Institut Pasteur, Paris, France. asiersc@pasteur.fr

ABSTRACT

Background: We have previously reported that CD4 T cells from some exposed uninfected (EU) Vietnamese intravenous drug users are relatively resistant to HIV infection in vitro. Here, we further characterized the restriction of viral replication in CD4 T cells from five EUs and assessed its persistence in serial samples.

Results: CD4 T cells and/or PBMC sampled during a period of between 2 and 6 years were challenged with replication-competent HIV-1 and other retroviral particles pseudotyped with envelope proteins of various tropisms. CCR5 expression and function in resistant CD4 T cells was evaluated. The step at which HIV-1 replication is restricted was investigated by real-time PCR quantification of HIV-1 reverse transcripts. We identified three patterns of durable HIV-1 restriction in EU CD4 T cells. CD4 T cells from four of the five EU subjects were resistant to HIV-1 R5 infection. In two cases this resistance was associated with low CCR5 surface expression, which was itself associated with heterozygous CCR5 mutations. In the other two cases, CD4 T cells were resistant to HIV-1 R5 infection despite normal CCR5 expression and signaling function, and normal beta-chemokine secretion upon CD4 T cell activation. Instead, restriction appeared to be due to enhanced CD4 T cell sensitivity to beta-chemokines in these two subjects. In the fifth EU subject the restriction involved post-entry steps of viral replication and affected not only HIV-1 but also other lentiviruses. The restriction was not overcome by a high viral inoculum, suggesting that it was not mediated by a saturable inhibitory factor.

Conclusion: Various constitutive mechanisms of CD4 T cell resistance to HIV-1 infection, affecting entry or post-entry steps of viral replication, are associated with resistance to HIV-1 in subjects who remain uninfected despite long-term high-risk behavior.

Show MeSH
Related in: MedlinePlus