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The cortical actin determines different susceptibility of naïve and memory CD4+ T cells to HIV-1 cell-to-cell transmission and infection.

Permanyer M, Pauls E, Badia R, Esté JA, Ballana E - PLoS ONE (2013)

Bottom Line: Memory CD4+ T cells are preferentially infected by HIV-1 compared to naïve cells.Using different actin remodeling compounds we demonstrate that efficiency of HIV-internalization was proportional to the actin polymerization of the target cell.In conclusion, the cortical actin density differentially affects the susceptibility to HIV-1 infection in naïve and memory CD4+ T cells by modulating the efficiency of HIV antigen internalization.

View Article: PubMed Central - PubMed

Affiliation: AIDS Research Institute-IrsiCaixa, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.

ABSTRACT
Memory CD4+ T cells are preferentially infected by HIV-1 compared to naïve cells. HIV-1 fusion and entry is a dynamic process in which the cytoskeleton plays an important role by allowing virion internalization and uncoating. Here, we evaluate the role of the cortical actin in cell-to-cell transfer of virus antigens and infection of target CD4+ T cells. Using different actin remodeling compounds we demonstrate that efficiency of HIV-internalization was proportional to the actin polymerization of the target cell. Naïve (CD45RA+) and memory (CD45RA-) CD4+ T cells could be phenotypically differentiated by the degree of cortical actin density and their capacity to capture virus. Thus, the higher cortical actin density of memory CD4+ T cells was associated to increased efficiency of HIV-antigen internalization and the establishment of a productive infection. Conversely, the lower cortical actin density in naïve CD4+ T cells restricted viral antigen transfer and consequently HIV-1 infection. In conclusion, the cortical actin density differentially affects the susceptibility to HIV-1 infection in naïve and memory CD4+ T cells by modulating the efficiency of HIV antigen internalization.

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Similar levels of viral fusion into naïve and memory CD4+ T cells.HEK293-T cells cotransfected with pNL4-3 and BlaM-Vpr plasmids were cocultured with primary resting CD4+ T cells in the presence or the absence of the anti-HIV-1 gp120 mAb IgGb12 (10 µg/ml) and the RT inhibitor AZT (1 µg/ml). Viral fusion was assessed by flow cytometry by measuring the percentage of CCF2-cleaved naïve (CD45RA+) and memory (CD45RA−) target CD4 T cells. (a) Dot plots of CCF2-loaded cells (FITC-labelled) versus CCF2-cleaved cells (Pacific blue-labelled) of a representative experiment are shown. (b) Percentage of CCF2-cleaved target cells normalized to memory CD4+ T cells in untreated condition. Mean and SD of two independent experiments is shown.
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pone-0079221-g004: Similar levels of viral fusion into naïve and memory CD4+ T cells.HEK293-T cells cotransfected with pNL4-3 and BlaM-Vpr plasmids were cocultured with primary resting CD4+ T cells in the presence or the absence of the anti-HIV-1 gp120 mAb IgGb12 (10 µg/ml) and the RT inhibitor AZT (1 µg/ml). Viral fusion was assessed by flow cytometry by measuring the percentage of CCF2-cleaved naïve (CD45RA+) and memory (CD45RA−) target CD4 T cells. (a) Dot plots of CCF2-loaded cells (FITC-labelled) versus CCF2-cleaved cells (Pacific blue-labelled) of a representative experiment are shown. (b) Percentage of CCF2-cleaved target cells normalized to memory CD4+ T cells in untreated condition. Mean and SD of two independent experiments is shown.

Mentions: Discrepant results have been reported regarding viral fusion of HIV-1 into naïve and memory T cell subsets [8], [10]. One previous report showed that naïve T cells were restricted at viral fusion [10], while the other study found only slightly diminished viral fusion in naïve T cells in one of two assays [8]. To find out whether HIV antigens are prevented from entering a subset of CD4+ target cells after cell-to-cell transfer, we evaluated the efficiency of viral entry in both T cell subtypes using the Vpr-β-lactamase-based entry assay [37]. HIVNL4-3 transfected Vpr-BlaM+ HEK293-T cells were cocultured with primary resting CD4+ T cells and fusion was measured in naïve (CD45RA+) and memory (CD45RA−) T cell subtypes by detection of the enzymatic cleavage of CCF2 dye using flow cytometry (Fig. 4a). We found that viral entry into naïve CD4+ T cells was reduced roughly 25% compared to memory CD4+ T cells but the difference was not statistically significant (Fig. 4b). Viral fusion into naïve CD4+ T cells was significantly inhibited by IgGb12 (95% reduction). Surprisingly, IgGb12 did not block viral fusion into memory CD4+ T cells as efficiently as into naïve CD4+ T cells (70% of inhibition compared to the untreated condition) (Fig. 4b). As expected, cleavage of CCF2 was not prevented by AZT. Taken together, these results indicate that after cell-to-cell transfer, viral entry is not restricted in any of the CD4+ T cells subtypes.


The cortical actin determines different susceptibility of naïve and memory CD4+ T cells to HIV-1 cell-to-cell transmission and infection.

Permanyer M, Pauls E, Badia R, Esté JA, Ballana E - PLoS ONE (2013)

Similar levels of viral fusion into naïve and memory CD4+ T cells.HEK293-T cells cotransfected with pNL4-3 and BlaM-Vpr plasmids were cocultured with primary resting CD4+ T cells in the presence or the absence of the anti-HIV-1 gp120 mAb IgGb12 (10 µg/ml) and the RT inhibitor AZT (1 µg/ml). Viral fusion was assessed by flow cytometry by measuring the percentage of CCF2-cleaved naïve (CD45RA+) and memory (CD45RA−) target CD4 T cells. (a) Dot plots of CCF2-loaded cells (FITC-labelled) versus CCF2-cleaved cells (Pacific blue-labelled) of a representative experiment are shown. (b) Percentage of CCF2-cleaved target cells normalized to memory CD4+ T cells in untreated condition. Mean and SD of two independent experiments is shown.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3823590&req=5

pone-0079221-g004: Similar levels of viral fusion into naïve and memory CD4+ T cells.HEK293-T cells cotransfected with pNL4-3 and BlaM-Vpr plasmids were cocultured with primary resting CD4+ T cells in the presence or the absence of the anti-HIV-1 gp120 mAb IgGb12 (10 µg/ml) and the RT inhibitor AZT (1 µg/ml). Viral fusion was assessed by flow cytometry by measuring the percentage of CCF2-cleaved naïve (CD45RA+) and memory (CD45RA−) target CD4 T cells. (a) Dot plots of CCF2-loaded cells (FITC-labelled) versus CCF2-cleaved cells (Pacific blue-labelled) of a representative experiment are shown. (b) Percentage of CCF2-cleaved target cells normalized to memory CD4+ T cells in untreated condition. Mean and SD of two independent experiments is shown.
Mentions: Discrepant results have been reported regarding viral fusion of HIV-1 into naïve and memory T cell subsets [8], [10]. One previous report showed that naïve T cells were restricted at viral fusion [10], while the other study found only slightly diminished viral fusion in naïve T cells in one of two assays [8]. To find out whether HIV antigens are prevented from entering a subset of CD4+ target cells after cell-to-cell transfer, we evaluated the efficiency of viral entry in both T cell subtypes using the Vpr-β-lactamase-based entry assay [37]. HIVNL4-3 transfected Vpr-BlaM+ HEK293-T cells were cocultured with primary resting CD4+ T cells and fusion was measured in naïve (CD45RA+) and memory (CD45RA−) T cell subtypes by detection of the enzymatic cleavage of CCF2 dye using flow cytometry (Fig. 4a). We found that viral entry into naïve CD4+ T cells was reduced roughly 25% compared to memory CD4+ T cells but the difference was not statistically significant (Fig. 4b). Viral fusion into naïve CD4+ T cells was significantly inhibited by IgGb12 (95% reduction). Surprisingly, IgGb12 did not block viral fusion into memory CD4+ T cells as efficiently as into naïve CD4+ T cells (70% of inhibition compared to the untreated condition) (Fig. 4b). As expected, cleavage of CCF2 was not prevented by AZT. Taken together, these results indicate that after cell-to-cell transfer, viral entry is not restricted in any of the CD4+ T cells subtypes.

Bottom Line: Memory CD4+ T cells are preferentially infected by HIV-1 compared to naïve cells.Using different actin remodeling compounds we demonstrate that efficiency of HIV-internalization was proportional to the actin polymerization of the target cell.In conclusion, the cortical actin density differentially affects the susceptibility to HIV-1 infection in naïve and memory CD4+ T cells by modulating the efficiency of HIV antigen internalization.

View Article: PubMed Central - PubMed

Affiliation: AIDS Research Institute-IrsiCaixa, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.

ABSTRACT
Memory CD4+ T cells are preferentially infected by HIV-1 compared to naïve cells. HIV-1 fusion and entry is a dynamic process in which the cytoskeleton plays an important role by allowing virion internalization and uncoating. Here, we evaluate the role of the cortical actin in cell-to-cell transfer of virus antigens and infection of target CD4+ T cells. Using different actin remodeling compounds we demonstrate that efficiency of HIV-internalization was proportional to the actin polymerization of the target cell. Naïve (CD45RA+) and memory (CD45RA-) CD4+ T cells could be phenotypically differentiated by the degree of cortical actin density and their capacity to capture virus. Thus, the higher cortical actin density of memory CD4+ T cells was associated to increased efficiency of HIV-antigen internalization and the establishment of a productive infection. Conversely, the lower cortical actin density in naïve CD4+ T cells restricted viral antigen transfer and consequently HIV-1 infection. In conclusion, the cortical actin density differentially affects the susceptibility to HIV-1 infection in naïve and memory CD4+ T cells by modulating the efficiency of HIV antigen internalization.

Show MeSH
Related in: MedlinePlus