The Interleukin-12–Mediated Pathway of Immune Events Is Dysfunctional in Human Immunodeficiency Virus–Infected Individuals

Interleukin-12 (IL-12) is a potentially critical factor in the immune response against human immunodeficiency virus (HIV) because it is important for regulating proliferation and interferon-γ (IFN-γ) production by T cells and natural killer (NK) cells, antigen presentation and accessory cell function by macrophages and dendritic cells, and cytolytic activities of cytotoxic T-lymphocyte cells and NK cells, which are all functions known to be dysfunctional in patients with acquired immune deficiency syndrome. Peripheral blood mononuclear cells (PBMC) from HIV-infected patients have been previously shown to be deficient in the ability to produce IL-12 in response to the bacterial pathogen Staphylococcus aureus Cowan. In this study, impaired IL-12 production in cells from PBMC of HIV-infected patients compared with healthy donors was observed across a broad panel of stimuli derived from infectious pathogens with or without priming with cytokines such as IFN-γ and IL-4, which amplify the IL-12 induction signal. Analysis of p40 and p35 mRNA accumulation showed that reductions in both subunits contribute to the lower IL-12 secretion of cells from HIV-infected individuals. PBMC from HIV-infected donors also failed to upregulate the IL-12 receptor β2 chain (IL-12Rβ2) in response to mitogenic stimuli. The expression of the IL-12Rβ2 gene could, however, be restored by in vitro exposure to rIL-12. Thus, it is possible that a primary IL-12 defect may lead to secondary deficiencies in expression of the genes for IL-12Rβ2 and IFN-γ, thus amplifying immune deficiency during HIV infection.

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Activation of Human NK Cells by Staphylococci and Lactobacilli Requires Cell Contact-Dependent Costimulation by Autologous Monocytes

Clinical and Vaccine Immunology ◽

10.1128/cdli.9.3.649-657.2002 ◽

2002 ◽

Vol 9 (3) ◽

pp. 649-657 ◽

Cited By ~ 17

Author(s):

D. Haller ◽

P. Serrant ◽

D. Granato ◽

E. J. Schiffrin ◽

S. Blum

Keyword(s):

Nk Cells ◽

Cell Activation ◽

Mononuclear Cells ◽

Nk Cell ◽

Interleukin 12 ◽

Accessory Cell ◽

Cell Contact ◽

Gram Positive ◽

Gram Positive Bacteria ◽

Ifn Γ

ABSTRACT NK cells are instrumental in innate immune responses, in particular for the early production of gamma interferon (IFN-γ) and other cytokines necessary to control certain bacterial, parasitic, and viral infections. NK cell-mediated effector functions are controlled by a fine balance between distinct receptors mediating activating and inhibitory signals; however, little is known about activating receptors on NK cells and their corresponding ligands. Several studies have shown that commensal lactobacilli isolated from the human gastrointestinal tract activate human mononuclear cells and are potent inducers of IFN-γ and monocyte-derived interleukin 12 (IL-12). NK cell activation was shown for Lactobacillus johnsonii La1. In this study the cellular mechanisms of in vitro NK cell activation by gram-positive bacteria were analyzed. Staphylococcus aureus- and L. johnsonii La1-mediated activation of CD3− CD16+ CD56+ human peripheral blood NK cells, including expression of the activation antigen CD69 and secretion of IFN-γ, required cell contact-dependent costimulation by autologous monocytes. S. aureus- and L. johnsonii-preactivated monocytes retained their capacity to induce NK cell activation. In contrast, cytokine-primed monocytes completely failed to induce NK cell activation unless bacteria were present. This suggests that phagocytosis of bacteria provided additional coactivation signals on accessory cells that may differ from those induced by tumor necrosis factor and IFN-γ. Blocking of costimulatory molecules by B7.1, B7.2, and IL-12 but not CD14 monoclonal antibodies inhibited S. aureus- and L. johnsonii-induced effector function of NK cells. Our data suggest an important role for accessory cell-derived signals in the process of NK cell activation by gram-positive bacteria.

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Human Immunodeficiency Virus gp120 Inhibits Interleukin-12 Secretion by Human Monocytes: An Indirect Interleukin-10–Mediated Effect

Blood ◽

10.1182/blood.v89.8.2842 ◽

1997 ◽

Vol 89 (8) ◽

pp. 2842-2848 ◽

Cited By ~ 45

Author(s):

Y. Taoufik ◽

O. Lantz ◽

C. Wallon ◽

A. Charles ◽

E. Dussaix ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Hiv Infection ◽

Aureus Strain ◽

Interleukin 12 ◽

Similar Data ◽

Human Monocytes ◽

Mrna Accumulation ◽

Immunodeficiency Virus ◽

Monocytes And Macrophages ◽

Hiv Gp120

Abstract Interleukin-12 (IL-12), a cytokine with in vitro and in vivo immunomodulatory effects, is produced mostly by activated monocytes and macrophages. To study the effect of human immunodeficiency virus (HIV) infection on IL-12 production, we investigated the expression of IL-12 at mRNA and protein levels by human monocytes preincubated with HIV-gp120. In these conditions, we show that monocytes have a decreased ability to express IL-12 mRNA subunits and to produce IL-12 p40 and bioactive p70 proteins in response to Staphylococcus aureus strain cowan I (SAC). We showed that in human monocyte cultures, HIV-gp120 induces a significant IL-10 synthesis, which in turn inhibits IL-12 subunits mRNA accumulation and protein secretion after SAC-activation. Similar data were obtained with human macrophages. These results suggest that, during HIV infection, gp120 induces in uninfected monocytes and macrophages IL-10/IL-12 disregulation, which can alter immune response.

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Contribution of Natural Killer Cells to Inhibition of Angiogenesis by Interleukin-12

Blood ◽

10.1182/blood.v93.5.1612 ◽

1999 ◽

Vol 93 (5) ◽

pp. 1612-1621 ◽

Cited By ~ 127

Author(s):

Lei Yao ◽

Cecilia Sgadari ◽

Keizo Furuke ◽

Eda T. Bloom ◽

Julie Teruya-Feldstein ◽

...

Keyword(s):

Endothelial Cells ◽

Nk Cells ◽

Natural Killer ◽

Cell Function ◽

Nk Cell ◽

Primary Cultures ◽

Interleukin 12 ◽

Ifn Γ

Abstract Interleukin-12 (IL-12) inhibits angiogenesis in vivo by inducing interferon-γ (IFN-γ) and other downstream mediators. Here, we report that neutralization of natural killer (NK) cell function with antibodies to either asialo GM1 or NK 1.1 reversed IL-12 inhibition of basic fibroblast growth factor (bFGF)-induced angiogenesis in athymic mice. By immunohistochemistry, those sites where bFGF-induced neovascularization was inhibited by IL-12 displayed accumulation of NK cells and the presence of IP-10–positive cells. Based on expression of the cytolytic mediators perforin and granzyme B, the NK cells were locally activated. Experimental Burkitt lymphomas treated locally with IL-12 displayed tumor tissue necrosis, vascular damage, and NK-cell infiltration surrounding small vessels. After activation in vitro with IL-12, NK cells from nude mice became strongly cytotoxic for primary cultures of syngeneic aortic endothelial cells. Cytotoxicity was neutralized by antibodies to IFN-γ. These results document that NK cells are required mediators of angiogenesis inhibition by IL-12, and provide evidence that NK-cell cytotoxicity of endothelial cells is a potential mechanism by which IL-12 can suppress neovascularization.

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Response to Superantigen Stimulation in Peripheral Blood Mononuclear Cells from Children Perinatally Infected with Human Immunodeficiency Virus and Receiving Highly Active Antiretroviral Therapy

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.11.5.957-962.2004 ◽

2004 ◽

Vol 11 (5) ◽

pp. 957-962 ◽

Cited By ~ 5

Author(s):

Thomas W. McCloskey ◽

Viraga Haridas ◽

Lucy Pontrelli ◽

Savita Pahwa

Keyword(s):

Human Immunodeficiency Virus ◽

T Cells ◽

Antiretroviral Therapy ◽

Highly Active Antiretroviral Therapy ◽

Mononuclear Cells ◽

Peripheral Blood Mononuclear ◽

Highly Active ◽

Immunodeficiency Virus ◽

Blood Mononuclear Cells ◽

Ifn Γ

ABSTRACT Our understanding of the pathogenesis of perinatal human immunodeficiency virus (HIV) infection is still evolving. We sought to characterize the response to the bacterial superantigen Staphylococcus enterotoxin B (SEB) of lymphocytes from HIV-infected children receiving treatment with highly active antiretroviral therapy (HAART). Using the flow cytometric methodology, we quantified apoptosis, proliferation, cytokine production, and activation antigen upregulation in CD4 and CD8 T lymphocytes following in vitro stimulation of peripheral blood mononuclear cells (PBMCs) with SEB. The levels of proliferation, CD4 interleukin-2 (IL-2) production, CD8 gamma interferon (IFN-γ) production, and upregulation of CD69 expression by cells from HIV-infected children were indistinguishable from those by cells from controls. However, stimulation with SEB dramatically decreased the ratio of resting apoptotic cells to cycling apoptotic cells in the controls but not in the patients. In addition, unstimulated spontaneous apoptosis of CD4 T cells remained greater in the patients than in the controls. The percentages of IL-2-positive CD8 T cells and IFN-γ-positive CD4 T cells following SEB stimulation were significantly lower in the patients than in the controls. Our multiparameter approach was able to demonstrate differences in lymphocyte superantigen responsiveness in HIV-infected children receiving HAART in comparison to that in uninfected controls, notably, an apoptotic versus a proliferative response to stimulation.

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Infection with Vpr-Positive Human Immunodeficiency Virus Type 1 Impairs NK Cell Function Indirectly through Cytokine Dysregulation of Infected Target Cells

Journal of Virology ◽

10.1128/jvi.01979-07 ◽

2008 ◽

Vol 82 (14) ◽

pp. 7189-7200 ◽

Cited By ~ 16

Author(s):

Biswanath Majumder ◽

Narasimhan J. Venkatachari ◽

Shaylee O'Leary ◽

Velpandi Ayyavoo

Keyword(s):

Human Immunodeficiency Virus ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Cell Function ◽

Nk Cell ◽

Target Cells ◽

Immunodeficiency Virus ◽

Ifn Γ ◽

Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) infection has been implicated in impairing various aspects of NK cell function in viremic condition, and several viral factors contribute to these defects. Here, we evaluated the effect of HIV-1 Vpr on NK cell cytolytic function and cytokine (gamma interferon [IFN-γ]) production in the context of infection and exposure. Our data indicate that NK cells derived from a peripheral blood mononuclear cell culture infected in vitro with HIV-1 vpr(+) virus or exposed to recombinant Vpr protein exhibited reduced target cell killing in conjunction with diminished expression of CD107a and reduced IFN-γ production compared to their Vpr-negative counterparts. This Vpr-induced NK cell defect is in part through differential regulation of interleukin-12 and transforming growth factor β production by the infected target cells and concomitant activation of Smad3 signaling pathway. Collectively, these results illustrate the ability of Vpr to impair NK cell-mediated innate immune functions indirectly by dysregulating multiple cytokines in the infected target cells, thus increasing disease severity and affecting the final outcome in HIV-1 infection.

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Combined Stimulation with Interleukin-18 and Interleukin-12 Potently Induces Interleukin-8 Production by Natural Killer Cells

Journal of Innate Immunity ◽

10.1159/000477172 ◽

2017 ◽

Vol 9 (5) ◽

pp. 511-525 ◽

Cited By ~ 5

Author(s):

Sophie M. Poznanski ◽

Amanda J. Lee ◽

Tina Nham ◽

Evan Lusty ◽

Margaret J. Larché ◽

...

Keyword(s):

Immune Response ◽

Nk Cells ◽

Natural Killer ◽

Peripheral Blood ◽

Mononuclear Cells ◽

Nk Cell ◽

Critical Role ◽

Interleukin 12 ◽

Tnf Α ◽

Ifn Γ

The combination of interleukin (IL)-18 and IL-12 (IL-18+IL-12) potently stimulates natural killer (NK) cells, triggering an innate immune response to infections and cancers. Strategies exploiting the effects of IL-18+IL-12 have shown promise for cancer immunotherapy. However, studies have primarily characterized the NK cell response to IL-18+IL-12 in terms of interferon (IFN)-γ production, with little focus on other cytokines produced. IL-8 plays a critical role in activating and recruiting immune cells, but it also has tumor-promoting functions. IL-8 is classically produced by regulatory NK cells; however, cytotoxic NK cells do not typically produce IL-8. In this study, we uncover that stimulation with IL-18+IL-12 induces high levels of IL-8 production by ex vivo expanded and freshly isolated NK cells and NK cells in peripheral blood mononuclear cells. We further report that tumor necrosis factor (TNF)-α, produced by NK cells following IL-18+IL-12 stimulation, regulates IL-8 production. The IL-8 produced is in turn required for maximal IFN-γ and TNF-α production. These findings may have important implications for the immune response to infections and cancer immunotherapies. This study broadens our understanding of NK cell function and IL-18+IL-12 synergy by uncovering an unprecedented ability of IL-18+IL-12-activated peripheral blood NK cells to produce elevated levels of IL-8 and identifying the requirement for intermediates induced by IL-18+IL-12 for maximal cytokine production following stimulation.

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Natural Killer Cell Function Is Well Preserved in Asymptomatic Human Immunodeficiency Virus Type 2 (HIV-2) Infection but Similar to That of HIV-1 Infection When CD4 T-Cell Counts Fall

Journal of Virology ◽

10.1128/jvi.80.5.2529-2538.2006 ◽

2006 ◽

Vol 80 (5) ◽

pp. 2529-2538 ◽

Cited By ~ 27

Author(s):

Samuel Victor Nuvor ◽

Marianne van der Sande ◽

Sarah Rowland-Jones ◽

Hilton Whittle ◽

Assan Jaye

Keyword(s):

Human Immunodeficiency Virus ◽

T Cell ◽

Nk Cells ◽

Natural Killer ◽

Human Immunodeficiency Virus Type ◽

Nk Cell ◽

Cell Counts ◽

Immunodeficiency Virus ◽

Ifn Γ ◽

Hiv 1

ABSTRACT Natural killer (NK) cells are potent effectors of natural immunity and their activity prevents human immunodeficiency virus type 1 (HIV-1) viral entry and viral replication. We sought to determine whether NK immune responses are associated with different clinical course of HIV-1 and HIV-2 infections. A cross-sectional analysis of NK cell responses was undertaken in 30 HIV-1 and 30 HIV-2 subjects in each of three categories of CD4+-T-cell counts (>500, 200 to 500, and <200 cells/μl) and in 50 HIV-uninfected control subjects. Lytic activity and gamma interferon (IFN-γ) secretion were measured by chromium release and enzyme-linked immunospot assays, respectively. Flow cytometry was used to assess intracellular cytokines and chemokines. Levels of NK cytotoxicity were significantly higher in HIV-2 than in HIV-1 infections in subjects with high CD4+-T-cell counts and were similar to that of the healthy controls. In these HIV-2 subjects, cytolytic activity was positively correlated to NK cell count and inversely related to plasma viremia. Levels of intracellular MIP-1β, RANTES, tumor necrosis factor alpha, and IFN-γ produced by NK CD56bright cells were significantly higher in HIV-2- than HIV-1-infected subjects with high CD4+-T-cell counts but fell to similar levels as CD4 counts dropped. The data suggest efficient cytolytic and chemokine-suppressive activity of NK cells early in HIV-2 infection, which is associated with high CD4+ T-cell counts. Enhancement of these functions may be important in immune-based therapy to control HIV disease.

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Yeast-Derived Human Immunodeficiency Virus Type 1 p55gag Virus-Like Particles Activate Dendritic Cells (DCs) and Induce Perforin Expression in Gag-Specific CD8+ T Cells by Cross-Presentation of DCs

Journal of Virology ◽

10.1128/jvi.77.19.10250-10259.2003 ◽

2003 ◽

Vol 77 (19) ◽

pp. 10250-10259 ◽

Cited By ~ 60

Author(s):

Yasuko Tsunetsugu-Yokota ◽

Yuko Morikawa ◽

Maya Isogai ◽

Ai Kawana-Tachikawa ◽

Takashi Odawara ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

T Cells ◽

Dendritic Cells ◽

Mononuclear Cells ◽

Interleukin 12 ◽

Virus Like Particles ◽

Cross Presentation ◽

Immunodeficiency Virus ◽

Dc Maturation

ABSTRACT To evaluate the immunogenicity of human immunodeficiency virus (HIV) type 1 p55 gag virus-like particles (VLPs) released by budding from yeast spheroplasts, we have analyzed the effects of yeast VLPs on monocyte-derived dendritic cells (DCs). Yeast VLPs were efficiently incorporated into DCs via both macropinocytosis and endocytosis mediated by mannose-recognizing receptors, but not the mannose receptor. The uptake of yeast VLPs induced DC maturation and enhanced cytokine production, notably, interleukin-12 p70. We showed that yeast membrane components may contribute to DC maturation partly through Toll-like receptor 2 signaling. Thus, Gag particles encapsulated by yeast membrane may have an advantage in stimulating Gag-specific immune responses. We found that yeast VLPs, but not the control yeast membrane fraction, were able to activate both CD4+ and CD8+ T cells of HIV-infected individuals. We tested the effect of cross-presentation of VLP by DCs in two subjects recruited into a long-term nonprogressor-slow progressor cohort. When yeast VLP-loaded DCs of these patients were cocultured with peripheral blood mononuclear cells for 7 days, approximately one-third of the Gag-specific CD8+ T cells were activated and became perforin positive. However, some of the Gag-specific CD8+ T cells appeared to be lost during in vitro culture, especially in a patient with a high virus load. Our results suggest that DCs loaded with yeast VLPs can activate Gag-specific memory CD8+ T cells to become effector cells in chronically HIV-infected individuals, but there still remain unresponsive Gag-specific T-cell populations in these patients.

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