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HIV-1 Vpr triggers natural killer cell-mediated lysis of infected cells through activation of the ATR-mediated DNA damage response.

Ward J, Davis Z, DeHart J, Zimmerman E, Bosque A, Brunetta E, Mavilio D, Planelles V, Barker E - PLoS Pathog. (2009)

Bottom Line: The presence of ULBP-1 and ULBP-2 on HIV-1 infected cells is dependent on the ability of Vpr to associate with a protein complex know as Cullin 4a (Cul4a)/damaged DNA binding protein 1 (DDB1) and Cul4a-associated factor-1(DCAF-1) E3 ubiquitin ligase (Cul4a(DCAF-1)).When T-cell blasts are infected with a vpr-deficient HIV-1, NK cells are impaired in killing the infected cells.Thus, HIV-1 Vpr actively triggers the expression of the ligands to the NK cell activation receptor.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, State University of New York, Upstate Medical University, Syracuse, New York, United States of America.

ABSTRACT
Natural killer (NK) cells are stimulated by ligands on virus-infected cells. We have recently demonstrated that NK cells respond to human immunodeficiency virus type-1 (HIV-1)-infected autologous T-cells, in part, through the recognition of ligands for the NK cell activating receptor NKG2D on the surface of the infected cells. Uninfected primary CD4(pos) T-cell blasts express little, if any, NKG2D ligands. In the present study we determined the mechanism through which ligands for NKG2D are induced on HIV-1-infected cells. Our studies reveal that expression of vpr is necessary and sufficient to elicit the expression of NKG2D ligands in the context of HIV-1 infection. Vpr specifically induces surface expression of the unique-long 16 binding proteins (ULBP)-1 and ULBP-2, but not ULBP-3, MHC class I-related chain molecules (MIC)-A or MIC-B. In these studies we also demonstrated that Vpr increases the level of ULBP-1 and ULBP-2 mRNA in primary CD4(pos) T-cell blasts. The presence of ULBP-1 and ULBP-2 on HIV-1 infected cells is dependent on the ability of Vpr to associate with a protein complex know as Cullin 4a (Cul4a)/damaged DNA binding protein 1 (DDB1) and Cul4a-associated factor-1(DCAF-1) E3 ubiquitin ligase (Cul4a(DCAF-1)). ULBP-1 and -2 expression by Vpr is also dependent on activation of the DNA damage sensor, ataxia telangiectasia and rad-3-related kinase (ATR). When T-cell blasts are infected with a vpr-deficient HIV-1, NK cells are impaired in killing the infected cells. Thus, HIV-1 Vpr actively triggers the expression of the ligands to the NK cell activation receptor.

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Infected primary CD4pos T-cells express NKG2D ligands.DHIV (A) and HIV-1NL4/3 (B) -infected primary T-cell blasts and uninfected CD4pos T-cells were surface stained with fluorochrome-conjugated anti-CD4 Ab and a fusion protein of human NKG2D and the Fc portion of human IgG1 along fluorochrome-conjugated goat anti-human IgG1. All cells were stained intracellularly for HIV-1 p24 antigen (Ag). Histograms were derived following acquisition on a flow cytometer of either 104 viable cells [(for uninfected cells) blue line] or 104 viable CD4neg cells and HIV-1 p24 Agpos infected cells (red line). As controls (green line), cells were stained with secondary Ab alone. This figure is representative of five separate experiments.
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ppat-1000613-g001: Infected primary CD4pos T-cells express NKG2D ligands.DHIV (A) and HIV-1NL4/3 (B) -infected primary T-cell blasts and uninfected CD4pos T-cells were surface stained with fluorochrome-conjugated anti-CD4 Ab and a fusion protein of human NKG2D and the Fc portion of human IgG1 along fluorochrome-conjugated goat anti-human IgG1. All cells were stained intracellularly for HIV-1 p24 antigen (Ag). Histograms were derived following acquisition on a flow cytometer of either 104 viable cells [(for uninfected cells) blue line] or 104 viable CD4neg cells and HIV-1 p24 Agpos infected cells (red line). As controls (green line), cells were stained with secondary Ab alone. This figure is representative of five separate experiments.

Mentions: We tested the binding of soluble NKG2D as a measure of ligand expression in PBMC from five individuals, in the presence or absence of in vitro DHIV infection. As seen in Figure 1A, CD4pos T-cells infected with DHIV wild type (WT) expressed NKG2D ligands [MFI = 687 for infected cells (HIV-1 p24 Agpos/CD4neg) compared with MFI = 159 for uninfected control]. Experiments were performed in parallel for a total of 5 donors and the statistical difference in MFI between the infected and uninfected groups in five individuals was p<0.01 based on the Student's t-test. Uninfected cells did not detectably express NKG2D ligands (MFI = 152 for uninfected cells compared with MFI = 159 for secondary Ab staining). Within the infected population, only the HIV-1 p24 Agpos cells, but not the p24neg in the same culture, expressed NKG2D ligands (see Figures 1 and S2). Therefore, we conclude that NKG2D is not induced on uninfected, bystander cells. DHIV does not encode the envelope glycoprotein; however NKG2D ligands are also induced on envelope-expressing HIV-1NL4/3-infected cells (Figure 1B). DHIV is derived from HIV-1NL4/3. Thus, DHIV-infected cells express NKG2D ligands on their cell surface.


HIV-1 Vpr triggers natural killer cell-mediated lysis of infected cells through activation of the ATR-mediated DNA damage response.

Ward J, Davis Z, DeHart J, Zimmerman E, Bosque A, Brunetta E, Mavilio D, Planelles V, Barker E - PLoS Pathog. (2009)

Infected primary CD4pos T-cells express NKG2D ligands.DHIV (A) and HIV-1NL4/3 (B) -infected primary T-cell blasts and uninfected CD4pos T-cells were surface stained with fluorochrome-conjugated anti-CD4 Ab and a fusion protein of human NKG2D and the Fc portion of human IgG1 along fluorochrome-conjugated goat anti-human IgG1. All cells were stained intracellularly for HIV-1 p24 antigen (Ag). Histograms were derived following acquisition on a flow cytometer of either 104 viable cells [(for uninfected cells) blue line] or 104 viable CD4neg cells and HIV-1 p24 Agpos infected cells (red line). As controls (green line), cells were stained with secondary Ab alone. This figure is representative of five separate experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2747015&req=5

ppat-1000613-g001: Infected primary CD4pos T-cells express NKG2D ligands.DHIV (A) and HIV-1NL4/3 (B) -infected primary T-cell blasts and uninfected CD4pos T-cells were surface stained with fluorochrome-conjugated anti-CD4 Ab and a fusion protein of human NKG2D and the Fc portion of human IgG1 along fluorochrome-conjugated goat anti-human IgG1. All cells were stained intracellularly for HIV-1 p24 antigen (Ag). Histograms were derived following acquisition on a flow cytometer of either 104 viable cells [(for uninfected cells) blue line] or 104 viable CD4neg cells and HIV-1 p24 Agpos infected cells (red line). As controls (green line), cells were stained with secondary Ab alone. This figure is representative of five separate experiments.
Mentions: We tested the binding of soluble NKG2D as a measure of ligand expression in PBMC from five individuals, in the presence or absence of in vitro DHIV infection. As seen in Figure 1A, CD4pos T-cells infected with DHIV wild type (WT) expressed NKG2D ligands [MFI = 687 for infected cells (HIV-1 p24 Agpos/CD4neg) compared with MFI = 159 for uninfected control]. Experiments were performed in parallel for a total of 5 donors and the statistical difference in MFI between the infected and uninfected groups in five individuals was p<0.01 based on the Student's t-test. Uninfected cells did not detectably express NKG2D ligands (MFI = 152 for uninfected cells compared with MFI = 159 for secondary Ab staining). Within the infected population, only the HIV-1 p24 Agpos cells, but not the p24neg in the same culture, expressed NKG2D ligands (see Figures 1 and S2). Therefore, we conclude that NKG2D is not induced on uninfected, bystander cells. DHIV does not encode the envelope glycoprotein; however NKG2D ligands are also induced on envelope-expressing HIV-1NL4/3-infected cells (Figure 1B). DHIV is derived from HIV-1NL4/3. Thus, DHIV-infected cells express NKG2D ligands on their cell surface.

Bottom Line: The presence of ULBP-1 and ULBP-2 on HIV-1 infected cells is dependent on the ability of Vpr to associate with a protein complex know as Cullin 4a (Cul4a)/damaged DNA binding protein 1 (DDB1) and Cul4a-associated factor-1(DCAF-1) E3 ubiquitin ligase (Cul4a(DCAF-1)).When T-cell blasts are infected with a vpr-deficient HIV-1, NK cells are impaired in killing the infected cells.Thus, HIV-1 Vpr actively triggers the expression of the ligands to the NK cell activation receptor.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, State University of New York, Upstate Medical University, Syracuse, New York, United States of America.

ABSTRACT
Natural killer (NK) cells are stimulated by ligands on virus-infected cells. We have recently demonstrated that NK cells respond to human immunodeficiency virus type-1 (HIV-1)-infected autologous T-cells, in part, through the recognition of ligands for the NK cell activating receptor NKG2D on the surface of the infected cells. Uninfected primary CD4(pos) T-cell blasts express little, if any, NKG2D ligands. In the present study we determined the mechanism through which ligands for NKG2D are induced on HIV-1-infected cells. Our studies reveal that expression of vpr is necessary and sufficient to elicit the expression of NKG2D ligands in the context of HIV-1 infection. Vpr specifically induces surface expression of the unique-long 16 binding proteins (ULBP)-1 and ULBP-2, but not ULBP-3, MHC class I-related chain molecules (MIC)-A or MIC-B. In these studies we also demonstrated that Vpr increases the level of ULBP-1 and ULBP-2 mRNA in primary CD4(pos) T-cell blasts. The presence of ULBP-1 and ULBP-2 on HIV-1 infected cells is dependent on the ability of Vpr to associate with a protein complex know as Cullin 4a (Cul4a)/damaged DNA binding protein 1 (DDB1) and Cul4a-associated factor-1(DCAF-1) E3 ubiquitin ligase (Cul4a(DCAF-1)). ULBP-1 and -2 expression by Vpr is also dependent on activation of the DNA damage sensor, ataxia telangiectasia and rad-3-related kinase (ATR). When T-cell blasts are infected with a vpr-deficient HIV-1, NK cells are impaired in killing the infected cells. Thus, HIV-1 Vpr actively triggers the expression of the ligands to the NK cell activation receptor.

Show MeSH
Related in: MedlinePlus