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Trifone C, Salido J, Ruiz MJ, Leng L, Quiroga MF, Salomón H, Bucala R, Ghiglione Y, Turk G. Interaction Between Macrophage Migration Inhibitory Factor and CD74 in Human Immunodeficiency Virus Type I Infected Primary Monocyte-Derived Macrophages Triggers the Production of Proinflammatory Mediators and Enhances Infection of Unactivated CD4 + T Cells. Front Immunol 2018; 9:1494. [PMID: 29997630 PMCID: PMC6030361 DOI: 10.3389/fimmu.2018.01494] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 06/15/2018] [Indexed: 11/13/2022] Open
Abstract
Understanding the mechanisms of human immunodeficiency virus type I (HIV-1) pathogenesis would facilitate the identification of new therapeutic targets to control the infection in face of current antiretroviral therapy limitations. CD74 membrane expression is upregulated in HIV-1-infected cells and the magnitude of its modulation correlates with immune hyperactivation in HIV-infected individuals. In addition, plasma level of the CD74 activating ligand macrophage migration inhibitory factor (MIF) is increased in infected subjects. However, the role played by MIF/CD74 interaction in HIV pathogenesis remains unexplored. Here, we studied the effect of MIF/CD74 interaction on primary HIV-infected monocyte-derived macrophages (MDMs) and its implications for HIV immunopathogenesis. Confocal immunofluorescence analysis of CD74 and CD44 (the MIF signal transduction co-receptor) expression indicated that both molecules colocalized at the plasma membrane specifically in wild-type HIV-infected MDMs. Treatment of infected MDMs with MIF resulted in an MIF-dependent increase in TLR4 expression. Similarly, there was a dose-dependent increase in the production of IL-6, IL-8, TNFα, IL-1β, and sICAM compared to the no-MIF condition, specifically from infected MDMs. Importantly, the effect observed on IL-6, IL-8, TNFα, and IL-1β was abrogated by impeding MIF interaction with CD74. Moreover, the use of a neutralizing αMIF antibody or an MIF antagonist reverted these effects, supporting the specificity of the results. Treatment of unactivated CD4+ T-cells with MIF-treated HIV-infected MDM-derived culture supernatants led to enhanced permissiveness to HIV-1 infection. This effect was lost when CD4+ T-cells were treated with supernatants derived from infected MDMs in which CD74/MIF interaction had been blocked. Moreover, the enhanced permissiveness of unactivated CD4+ T-cells was recapitulated by exogenous addition of IL-6, IL-8, IL-1β, and TNFα, or abrogated by neutralizing its biological activity using specific antibodies. Results obtained with BAL and NL4-3 HIV laboratory strains were reproduced using transmitted/founder primary isolates. This evidence indicated that MIF/CD74 interaction resulted in a higher production of proinflammatory cytokines from HIV-infected MDMs. This caused the generation of an inflammatory microenvironment which predisposed unactivated CD4+ T-cells to HIV-1 infection, which might contribute to viral spreading and reservoir seeding. Overall, these results support a novel role of the MIF/CD74 axis in HIV pathogenesis that deserves further investigation.
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Affiliation(s)
- César Trifone
- CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina
| | - Jimena Salido
- CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina
| | - María Julia Ruiz
- CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina
| | - Lin Leng
- Department of Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - María Florencia Quiroga
- CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina
| | - Horacio Salomón
- CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina
| | - Richard Bucala
- Department of Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Yanina Ghiglione
- CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina
| | - Gabriela Turk
- CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina
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Monocyte-lymphocyte fusion induced by the HIV-1 envelope generates functional heterokaryons with an activated monocyte-like phenotype. Exp Cell Res 2017; 352:9-19. [PMID: 28132881 DOI: 10.1016/j.yexcr.2017.01.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 01/23/2017] [Accepted: 01/25/2017] [Indexed: 02/08/2023]
Abstract
Enveloped viruses induce cell-cell fusion when infected cells expressing viral envelope proteins interact with target cells, or through the contact of cell-free viral particles with adjoining target cells. CD4+ T lymphocytes and cells from the monocyte-macrophage lineage express receptors for HIV envelope protein. We have previously reported that lymphoid Jurkat T cells expressing the HIV-1 envelope protein (Env) can fuse with THP-1 monocytic cells, forming heterokaryons with a predominantly myeloid phenotype. This study shows that the expression of monocytic markers in heterokaryons is stable, whereas the expression of lymphoid markers is mostly lost. Like THP-1 cells, heterokaryons exhibited FcγR-dependent phagocytic activity and showed an enhanced expression of the activation marker ICAM-1 upon stimulation with PMA. In addition, heterokaryons showed morphological changes compatible with maturation, and high expression of the differentiation marker CD11b in the absence of differentiation-inducing agents. No morphological change nor increase in CD11b expression were observed when an HIV-fusion inhibitor blocked fusion, or when THP-1 cells were cocultured with Jurkat cells expressing a non-fusogenic Env protein, showing that differentiation was not induced merely by cell-cell interaction but required cell-cell fusion. Inhibition of TLR2/TLR4 signaling by a TIRAP inhibitor greatly reduced the expression of CD11b in heterokaryons. Thus, lymphocyte-monocyte heterokaryons induced by HIV-1 Env are stable and functional, and fusion prompts a phenotype characteristic of activated monocytes via intracellular TLR2/TLR4 signaling.
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Leibrand CR, Paris JJ, Ghandour MS, Knapp PE, Kim WK, Hauser KF, McRae M. HIV-1 Tat disrupts blood-brain barrier integrity and increases phagocytic perivascular macrophages and microglia in the dorsal striatum of transgenic mice. Neurosci Lett 2017; 640:136-143. [PMID: 28057474 DOI: 10.1016/j.neulet.2016.12.073] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 12/19/2016] [Accepted: 12/31/2016] [Indexed: 12/01/2022]
Abstract
HIV-1 infection results in blood-brain barrier (BBB) disruption, which acts as a rate-limiting step for HIV-1 entry into the CNS and for subsequent neuroinflammatory/neurotoxic actions. One mechanism by which HIV may destabilize the BBB involves actions of the HIV-1 regulatory protein, trans-activator of transcription (Tat). We utilized a conditional, Tat-expressing transgenic murine model to examine the influence of Tat1-86 expression on BBB integrity and to assess the relative numbers of phagocytic perivascular macrophages and microglia within the CNS in vivo. The effects of Tat exposure on sodium-fluorescein (Na-F; 0.376kDa), horseradish peroxidase (HRP; 44kDa), and Texas Red-labeled dextran (70kDa) leakage into the brain were assessed in Tat-exposed (Tat+) and control (Tat-) mice. Exposure to HIV-1 Tat significantly increased both Na-F and HRP, but not the larger sized Texas Red-labeled dextran, confirming BBB breakdown and also suggesting the breach was limited to molecules <70kDa. Additionally, at 5 d after Tat induction, Alexa Fluor® 488-labeled dextran was bilaterally infused into the lateral ventricles 5 d before the termination of the experiment. Within the caudate/putamen, Tat induction increased the proportion of dextran-labeled Iba-1+ phagocytic perivascular macrophages (∼5-fold) and microglia (∼3-fold) compared to Tat- mice. These data suggest that HIV-1 Tat exposure is sufficient to destabilize BBB integrity and to increase the presence of activated, phagocytic, perivascular macrophages and microglia in an in vivo model of neuroAIDS.
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Affiliation(s)
- Crystal R Leibrand
- Department of Pharmacotherapy and Outcomes Science, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Jason J Paris
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, P.O. Box 980613, Richmond, VA 23298, USA
| | - M Said Ghandour
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, P.O. Box 980709, Richmond, VA 23298, USA
| | - Pamela E Knapp
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, P.O. Box 980613, Richmond, VA 23298, USA; Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, P.O. Box 980709, Richmond, VA 23298, USA; Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Medical College of Virginia (MCV) Campus, Richmond, VA 23298, USA
| | - Woong-Ki Kim
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA 23507, USA
| | - Kurt F Hauser
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, P.O. Box 980613, Richmond, VA 23298, USA; Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, P.O. Box 980709, Richmond, VA 23298, USA; Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Medical College of Virginia (MCV) Campus, Richmond, VA 23298, USA
| | - MaryPeace McRae
- Department of Pharmacotherapy and Outcomes Science, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23298, USA.
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Hudig D, Hunter KW, Diamond WJ, Redelman D. Properties of human blood monocytes. II. Monocytes from healthy adults are highly heterogeneous within and among individuals. CYTOMETRY PART B-CLINICAL CYTOMETRY 2013; 86:121-34. [PMID: 24327358 DOI: 10.1002/cyto.b.21141] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Revised: 09/17/2013] [Accepted: 10/18/2013] [Indexed: 01/04/2023]
Abstract
BACKGROUND Human blood monocytes are known to include subsets defined by the expression of CD14 and CD16 but otherwise are often assumed to be relatively homogeneous. However, we had observed additional heterogeneity that led us to a more extensive examination of monocytes. METHODS Blood samples from 200 healthy adults without known immunological abnormalities were examined by analysis with a hematology analyzer and by flow cytometry (FCM) to determine leukocyte differential counts, to identify subsets and to measure expression of monocyte-associated molecules. RESULTS The estimated cell counts of monocytes, neutrophils, total lymphocytes, and T cells all varied to a similar extent, that is, ±30-35%. The fractions of monocyte subsets defined by CD14 and CD16 or by CD163 expression also varied among individuals. FCM examinations showed that all the monocyte-associated molecules that were examined varied in expression in this increasing order-CD244, CD4, CD38, CD91, CD11b, toll-like receptor 2 (TLR2), TIA-1, CD14 (on CD14(Br+) cells), CD86, CD80, HLA-DQ, CD33, and HLA-DR. CONCLUSIONS Human blood monocytes are heterogeneous among healthy adults with respect to cell counts, subsets, and the levels of expression of monocyte-associated molecules. An increase in the "non-classical" (CD14(Lo/Neg) /CD16(+) ) monocyte subset or in the expression of CD11b or TLR2 have known diagnostic/prognostic implications. CD244 and CD4 have well-defined functions on lymphocytes but perform unknown activities on monocytes although their expression appears more narrowly controlled. Together, these data suggest that monocytes should be more extensively examined in both clinical and basic contexts.
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Affiliation(s)
- Dorothy Hudig
- Department of Microbiology and Immunology, University of Nevada School of Medicine, Reno, Nevada, 89557
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Garg A, Spector SA. HIV type 1 gp120-induced expansion of myeloid derived suppressor cells is dependent on interleukin 6 and suppresses immunity. J Infect Dis 2013; 209:441-51. [PMID: 23999600 DOI: 10.1093/infdis/jit469] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Factors responsible for myeloid-derived suppressor cell (MDSC) expansion and T-cell dysfunction during human immunodeficiency virus type 1 (HIV) infection are unknown. This study investigated the role of MDSCs during HIV infection. METHODS Peripheral blood mononuclear cells (PBMCs) were cultured with gp120 and infectious or inactivated HIV, with or without anti-interleukin 6 (IL-6) antibody. CD33(+), CD4(+), and CD8(+) cells were isolated from PBMCs and cocultured in the presence or absence of inducible nitric oxide synthase (iNOS), reactive oxygen species (ROS), and arginase 1 inhibitors. CD11b(+)CD33(+)CD14(+)HLA-DR(-/lo) MDSCs, phosphorylated STAT3 (pSTAT3), and CD4(+)CD25(+)FoxP3(+) cells were evaluated by flow cytometry. IL-6, interferon γ (IFN-γ), interleukin 10 (IL-10), and gp120 levels were quantified by an enzyme-linked immunosorbent assay. RESULTS MDSCs expanded when PBMCs were exposed to infectious or inactivated HIV. Exposure to gp120 led to MDSC expansion, with increases in IL-6 levels and pSTAT3 expression. Anti-IL-6 abrogated MDSC expansion and pSTAT3 expression. gp120-expanded CD33(+) MDSCs inhibited IFN-γ release from autologous T cells, which was restored upon ROS and iNOS inhibition. gp120-expanded CD33(+) MDSCs increased IL-10 and CD4(+)CD25(+)FoxP3(+) regulatory T-cell levels in CD4(+) T-cell cocultures. Finally, high frequencies of MDSCs were present in HIV-infected persons, compared with healthy controls. CONCLUSIONS These findings demonstrate that HIV gp120 induces IL-6 and MDSC expansion, which contributes to immune suppression by modulating cytokine and cellular responses.
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Affiliation(s)
- Ankita Garg
- Department of Pediatrics, Division of Infectious Diseases, University of California, San Diego, La Jolla
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Yadav A, Collman RG. CNS inflammation and macrophage/microglial biology associated with HIV-1 infection. J Neuroimmune Pharmacol 2009; 4:430-47. [PMID: 19768553 PMCID: PMC5935112 DOI: 10.1007/s11481-009-9174-2] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Accepted: 09/03/2009] [Indexed: 10/20/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) infection of the central nervous system (CNS) can result in neurological dysfunction with devastating consequences in a significant proportion of individuals with acquired immune deficiency syndrome. HIV-1 does not infect neurons directly but induces damage indirectly through the accumulation of activated macrophage/microglia (M/M) cells, some of which are infected, that release neurotoxic mediators including both cellular activation products and viral proteins. One mechanism for the accumulation of activated M/M involves the development in infected individuals of an activated peripheral blood monocyte population that traffics through the blood-brain barrier, a process that also serves to carry virus into CNS and establish local infection. A second mechanism involves the release by infected and activated M/M in the CNS of chemotactic mediators that recruit additional monocytes from the periphery. These activated M/M, some of which are infected, release a number of cytokines and small molecule mediators as well as viral proteins that act on bystander cells and in turn activate them, thus amplifying the cascade. These viral proteins and cellular products have neurotoxic properties as well, both directly and through induction of astrocyte dysfunction, which ultimately lead to neuronal injury and death. In patients effectively treated with antiretroviral therapy, frank dementia is now uncommon and has been replaced by milder forms of neurocognitive impairment, with less frequent and more focal neuropathology. This review summarizes key findings that support the critical role and mechanisms of monocyte/macrophage activation and inflammation as a major component for HIV-1 encephalitis or HIV-1 associated dementia.
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Affiliation(s)
- Anjana Yadav
- Department of Medicine and Center for AIDS Research, University of Pennsylvania School of Medicine, 522 Johnson Pavilion, 36th & Hamilton Walk, Philadelphia, PA 19104, USA
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Kim WK, Sun Y, Do H, Autissier P, Halpern EF, Piatak M, Lifson JD, Burdo TH, McGrath MS, Williams K. Monocyte heterogeneity underlying phenotypic changes in monocytes according to SIV disease stage. J Leukoc Biol 2009; 87:557-67. [PMID: 19843579 DOI: 10.1189/jlb.0209082] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Infection by HIV is associated with the expansion of monocytes expressing CD16 antigens, but the significance of this in HIV pathogenesis is largely unknown. In rhesus macaques, at least three subpopulations of blood monocytes were identified based on their expression of CD14 and CD16: CD14(high)CD16(-), CD14(high)CD16(low), and CD14(low)CD16(high). The phenotypes and functions of these subpopulations, including CD16(+) monocytes, were investigated in normal, uninfected rhesus macaques and macaques that were infected with SIV or chimeric SHIV. To assess whether these different monocyte subpopulations expand or contract in AIDS pathogenesis, we conducted a cross-sectional study of 54 SIV- or SHIV-infected macaques and 48 uninfected controls. The absolute numbers of monocyte populations were examined in acutely infected animals, chronically infected animals with no detectable plasma virus RNA, chronically infected animals with detectable plasma virus RNA, and animals that died with AIDS. The absolute numbers of CD14(high)CD16(low) and CD14(low)CD16(high) monocytes were elevated significantly in acutely infected animals and chronically infected animals with detectable plasma virus RNA compared with uninfected controls. Moreover, a significant, positive correlation was evident between the number of CD14(high)CD16(low) or CD14(low)CD16(high) monocytes and plasma viral load in the infected cohort. These data show the dynamic changes of blood monocytes, most notably, CD14(high)CD16(low) monocytes during lentiviral infection, which are specific to disease stage.
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Affiliation(s)
- Woong-Ki Kim
- Division of Viral Pathogenesis, Beth Israel Deaconess Medical Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Kim WK, Avarez X, Williams K. The role of monocytes and perivascular macrophages in HIV and SIV neuropathogenesis: information from non-human primate models. Neurotox Res 2005; 8:107-15. [PMID: 16260389 DOI: 10.1007/bf03033823] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Perivascular macrophages are located in the perivascular space of cerebral microvessels and thus uniquely situated at the intersection between the brain parenchyma and blood. Connections between the nervous and immune systems are mediated in part through these cells that are ideally located to sense perturbations in the periphery and turnover by cells entering the central nervous system (CNS) from the circulation. It has become clear that unique subsets of brain macrophages exist in normal and SIV- or HIV-infected brains, and perivascular macrophages and similar cells in the meninges and choroid plexus play a central role in lentiviral neuropathogenesis. Common to all these cell populations is their likely replacement within the CNS by monocytes. Studies of SIV-infected non-human primates and HIV-infected humans underscore the importance of virus-infected and activated monocytes, which traffic to the CNS from blood to become perivascular macrophages, potentially drive the blood-brain barrier damage and cause neuronal injury. This review summarizes what we know about SIV- and HIV-induced neuropathogenesis focusing on brain perivascular macrophages and their precursors in blood that may mediate HIV CNS infection and injury.
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Affiliation(s)
- W-K Kim
- Division of Viral Pathogenesis, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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Skinner NA, MacIsaac CM, Hamilton JA, Visvanathan K. Regulation of Toll-like receptor (TLR)2 and TLR4 on CD14dimCD16+ monocytes in response to sepsis-related antigens. Clin Exp Immunol 2005; 141:270-8. [PMID: 15996191 PMCID: PMC1809439 DOI: 10.1111/j.1365-2249.2005.02839.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Rapid overproduction of proinflammatory cytokines are characteristic of sepsis. CD14(dim)CD16(+) monocytes are thought to be major producers of cytokine and have been shown to be elevated in septic patients. Toll-like receptors (TLR) are pattern recognition receptors important in mediating the innate immune response and their activation can lead to production of cytokines. Using whole blood culture and flow cytometry we have investigated TLR2 and TLR4 regulation after stimulation with sepsis-relevant antigens [lipopolysaccharide (LPS), Staphylococcal enterotoxin B (SEB) and peptidoglycan (PGN)]. The percentage of CD14(dim)CD16(+) monocyte population expanded at 20 h post-stimulation, after a rise in tumour necrosis factor (TNF)-alpha and interleukin (IL)-6 at 2 h. A strong positive correlation between the percentage of CD14(dim)CD16(+) monocytes and secreted TNF-alpha was demonstrated (r = 0.72). Furthermore, we were able to induce expansion of the CD14(dim)CD16(+) population to approximately 35% of all monocytes with the addition of recombinant TNF-alpha to the whole blood culture. TLR4 was found to be expressed 2.5 times higher on CD14(dim)CD16(+) compared to CD14(+) CD16(-) monocytes, while TLR2 expression was similar in both subpopulations. The CD14(dim)CD16(+) and CD14(+) CD16(-) monocyte populations were different in their response to various antigens. LPS down-regulated TLR4 by 4.9 times in CD16(+) monocytes compared to only 2.3 times in CD16(-) monocytes at 2 h. LPS was able to up-regulate TLR2 by 6.2 times after 2 h, with no difference between the subpopulations. LPS further up-regulated TLR2 by 18.4 times after 20 h only in the CD14(+) CD16(-) population. PGN and SEB induced no significant changes in TLR2 or TLR4 expression. We hypothesize that following exposure to bacterial antigens, subsequent TNF-alpha drives a differentiation of monocytes into a CD14(dim)CD16(+) subpopulation.
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Affiliation(s)
- N A Skinner
- Staphylococcal and Streptococcal Group, Murdoch Children's Research Institute, Melbourne, Australia
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Kim WK, Corey S, Alvarez X, Williams K. Monocyte/macrophage traffic in HIV and SIV encephalitis. J Leukoc Biol 2003; 74:650-6. [PMID: 12960230 DOI: 10.1189/jlb.0503207] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
This short review focuses on the role of central nervous system (CNS) perivascular macrophages as targets of productive infection of the CNS. Data discussed include the importance of these cells as early targets of infection and their productive infection with AIDS. Many of the immune molecules on perivascular macrophages are also found on subsets of blood monocyte/macrophages, some of which are expanded during human immunodeficiency virus (HIV) infection. These observations paired with the known bone marrow (BM) origin of perivascular macrophages and the BM as a site of HIV infection underscore the importance of the study of monocyte populations in the BM and blood, which are activated and infected as a source of virus that enters the CNS. Data presented and discussed herein suggest a role of HIV-infected BM-derived monocytes as "Trojan horse" cells that traffic to the CNS to become perivascular macrophages. The study of such cells including their timing of infection, activation, and traffic and the role of HIV-specific immune responses controlling their accumulation in the CNS warrant study with regard to CNS neuropathogenesis.
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Affiliation(s)
- Woong-Ki Kim
- Division of Pathogenesis, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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Creery D, Angel JB, Aucoin S, Weiss W, Cameron WD, Diaz-Mitoma F, Kumar A. Nef protein of human immunodeficiency virus and lipopolysaccharide induce expression of CD14 on human monocytes through differential utilization of interleukin-10. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2002; 9:1212-21. [PMID: 12414752 PMCID: PMC130120 DOI: 10.1128/cdli.9.6.1212-1221.2002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We investigated the expression of membrane-bound CD14 (mCD14) on monocytes and soluble CD14 (sCD14) released into the culture supernatants of peripheral blood lymphocytes (PBMC) from human immunodeficiency virus (HIV)-infected individuals. Monocytes from HIV-positive individuals exhibited both enhanced mCD14 expression and sCD14 production in the PBMC culture supernatants compared to the levels of mCD14 and sCD14 in HIV-negative individuals. This enhanced mCD14 expression and sCD14 production in HIV-infected individuals may be due to the effects of cytokines, the bacterial product lipopolysaccharide (LPS), and/or the HIV regulatory antigens Tat and Nef. Interleukin-10 (IL-10), an immunoregulatory cytokine, as well as LPS enhanced mCD14 expression and the release of sCD14 in the culture supernatants. HIV-Nef, unlike Tat, enhanced mCD14 expression on monocytes but did not induce the release of sCD14 into the culture supernatants. Studies conducted to investigate the mechanism underlying HIV-Nef-induced mCD14 expression revealed that HIV-Nef upregulated mCD14 expression via a mechanism that does not involve endogenously produced IL-10. In contrast, LPS upregulated the expression of mCD14 and increased the release of sCD14 via a mechanism that involves, at least in part, endogenously produced IL-10. Furthermore, dexamethasone, an anti-inflammatory and immunosuppressive agent, inhibited HIV-Nef-induced CD14 expression in an IL-10-independent manner. In contrast, dexamethasone inhibited IL-10-dependent LPS-induced CD14 expression by interfering with IL-10-induced signals but not by blocking IL-10 production. These results suggest that HIV-Nef and IL-10 constitute biologically important modulators of CD14 expression which may influence immunobiological responses to bacterial infections in HIV disease.
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Affiliation(s)
- David Creery
- Department of Pediatrics, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
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Kamp W, Breij EC, Nottet HS, Berk MB. Interactions between major histocompatibility complex class II surface expression and HIV: implications for pathogenesis. Eur J Clin Invest 2001; 31:984-91. [PMID: 11737241 DOI: 10.1046/j.1365-2362.2001.00895.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Although it has been almost 20 years since the first cases of acquired immunodeficiency syndrome (AIDS) were documented, the pathogenesis is still not completely understood. Interactions between major histocompatibility complex (MHC) Class I and human immunodeficiency virus (HIV), resulting in down-regulation of MHC-I surface expression, have been reported to contribute to pathogenesis by suppressing the host's immune response. Interactions between MHC Class II and HIV have also been described, but it is unclear how these contribute to the pathogenesis. MHC-II surface expression on HIV-infected monocytes and monocytic cell lines has been described to be increased as well as decreased when compared to uninfected control monocytes. HIV-specific mechanisms appear to down-regulate MHC-II expression on blood monocytes during HIV-1 infection, whereas host mechanisms up-regulate MHC-II expression in response to infection of blood monocytes as well as brain macrophages. A balance between these two may determine MHC-II expression levels in individual patients. Altogether, HIV seems to be able to benefit from both low and high levels of MHC-II surface expression. The first results in reduced immune surveillance of the host, allowing the virus to replicate faster; the second increases infectivity of the virus as a result of higher MHC-II density on macrophages and virion particles.
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Affiliation(s)
- W Kamp
- Fight for Life Foundation, Amsterdam, the Netherlands
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13
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Grage‐Griebenow E, Flad H, Ernst M. Heterogeneity of human peripheral blood monocyte subsets. J Leukoc Biol 2001. [DOI: 10.1189/jlb.69.1.11] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
| | - H.‐D. Flad
- Immunology and Cell Biology, Research Center Borstel, Germany
| | - M. Ernst
- Immunology and Cell Biology, Research Center Borstel, Germany
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Ma X, Montaner LJ. Proinflammatory response and IL‐12 expression in HIV‐1 infection. J Leukoc Biol 2000. [DOI: 10.1189/jlb.68.3.383] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Xiaojing Ma
- The Wistar Institute, Philadelphia, Pennsylvania
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