Mycobacterium tuberculosis Diverts Alpha Interferon-Induced Monocyte Differentiation from Dendritic Cells into Immunoprivileged Macrophage-Like Host Cells

ABSTRACT Dendritic cells (DCs) are critical for initiating a pathogen-specific T-cell response. During chronic infections the pool of tissue DCs must be renewed by recruitment of both circulating DC progenitors and in loco differentiating monocytes. However, the interaction of monocytes with pathogens could affect their differentiation. Mycobacterium tuberculosis has been shown to variably interfere with the generation and function of antigen-presenting cells (APCs). In this study we found that when alpha interferon (IFN-α) is used as an inductor of monocyte differentiation, M. tuberculosis inhibits the generation of DCs, forcing the generation of immunoprivileged macrophage-like cells instead. Cells derived from M. tuberculosis-infected monocyte-derived macrophages (M. tuberculosis-infected MoMφ) retained CD14 without acquiring CD1 molecules and partially expressed B7.2 but did not up-regulate B7.1 and major histocompatibility complex (MHC) class I and II molecules. They synthesized tumor necrosis factor alpha and interleukin-10 (IL-10) but not IL-12. They also showed a reduced ability to induce proliferation and functional polarization of allogeneic T lymphocytes. Thus, in the presence of IFN-α, M. tuberculosis may hamper the renewal of potent APCs, such as DCs, generating a safe habitat for intracellular growth. M. tuberculosis-infected MoMφ, in fact, showed reduced expression of both signal 1 (CD1, MHC classes I and II) and signal 2 (B7.1 and B7.2), which are essential for mycobacterium-specific T-lymphocyte priming and/or activation. These data further suggest that M. tuberculosis has the ability to specifically interfere with monocyte differentiation. This ability may represent an effective M. tuberculosis strategy for eluding immune surveillance and persisting in the host.

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Infection of Human Dendritic Cells with a Mycobacterium tuberculosis sigE Mutant Stimulates Production of High Levels of Interleukin-10 but Low Levels of CXCL10: Impact on the T-Cell Response

Infection and Immunity ◽

10.1128/iai.01687-05 ◽

2006 ◽

Vol 74 (6) ◽

pp. 3296-3304 ◽

Cited By ~ 19

Author(s):

Elena Giacomini ◽

Ambar Sotolongo ◽

Elisabetta Iona ◽

Martina Severa ◽

Maria Elena Remoli ◽

...

Keyword(s):

T Cells ◽

Dendritic Cells ◽

Mycobacterium Tuberculosis ◽

Human Monocyte ◽

Interleukin 10 ◽

T Cell Response ◽

Interleukin 12 ◽

Necrosis Factor Alpha ◽

Effector Cells ◽

Human Dendritic Cells

ABSTRACT The Mycobacterium tuberculosis genome encodes 13 sigma factors. We have previously shown that mutations in some of these transcriptional activators render M. tuberculosis sensitive to various environmental stresses and can attenuate the virulence phenotype. In this work, we focused on extracytoplasmic factor σE and studied the effects induced by the deletion of its structural gene (sigE) in the infection of human monocyte-derived dendritic cells (MDDC). We found that the wild-type M. tuberculosis strain (H37Rv), the sigE mutant (ST28), and the complemented strain (ST29) were able to infect dendritic cells (DC) to similar extents, although at 4 days postinfection a reduced ability to grow inside MDDC was observed for the sigE mutant ST28. After mycobacterium capture, the majority of MDDC underwent full maturation and expressed both inflammatory cytokines, such as tumor necrosis factor alpha, and the regulatory cytokines interleukin-12 (IL-12), IL-18, and beta interferon (IFN-β). Conversely, a higher level of production of IL-10 was observed in ST28-infected MDDC compared to H37Rv- or ST29-infected cell results. However, in spite of the presence of IL-10, supernatants from ST28-infected DC induced IFN-γ production by T cells similarly to those from H37Rv-infected DC culture. On the other hand, IL-10 impaired CXCL10 production in sigE mutant-infected DC and, indeed, its neutralization restored CXCL10 secretion. In line with these results, supernatants from ST28-infected cells showed a decreased capability to recruit CXCR3+ CD4+ T cells compared to those obtained from H37Rv-infected DC culture. Thus, our findings suggest that the sigE mutant-induced secretion of IL-10 inhibits CXCL10 expression and, in turn, the recruitment of activated-effector cells involved in the formation of granulomas.

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The Secreted Protein Rv1860 of Mycobacterium tuberculosis Stimulates Human Polyfunctional CD8+T Cells

Clinical and Vaccine Immunology ◽

10.1128/cvi.00554-15 ◽

2016 ◽

Vol 23 (4) ◽

pp. 282-293 ◽

Cited By ~ 2

Author(s):

Vijaya Satchidanandam ◽

Naveen Kumar ◽

Sunetra Biswas ◽

Rajiv S. Jumani ◽

Chandni Jain ◽

...

Keyword(s):

T Cells ◽

Mycobacterium Tuberculosis ◽

T Cell ◽

Mononuclear Cells ◽

Interleukin 10 ◽

T Cell Response ◽

Peripheral Blood Mononuclear ◽

Necrosis Factor Alpha ◽

Content Type ◽

Latent Tb Infection

ABSTRACTWe previously reported that Rv1860 protein fromMycobacterium tuberculosisstimulated CD4+and CD8+T cells secreting gamma interferon (IFN-γ) in healthy purified protein derivative (PPD)-positive individuals and protected guinea pigs immunized with a DNA vaccine and a recombinant poxvirus expressing Rv1860 from a challenge with virulentM. tuberculosis. We now show Rv1860-specific polyfunctional T (PFT) cell responses in the blood of healthy latentlyM. tuberculosis-infected individuals dominated by CD8+T cells, using a panel of 32 overlapping peptides spanning the length of Rv1860. Multiple subsets of CD8+PFT cells were significantly more numerous in healthy latently infected volunteers (HV) than in tuberculosis (TB) patients (PAT). The responses of peripheral blood mononuclear cells (PBMC) from PAT to the peptides of Rv1860 were dominated by tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10) secretions, the former coming predominantly from non-T cell sources. Notably, the pattern of the T cell response to Rv1860 was distinctly different from those of the widely studiedM. tuberculosisantigens ESAT-6, CFP-10, Ag85A, and Ag85B, which elicited CD4+T cell-dominated responses as previously reported in other cohorts. We further identified a peptide spanning amino acids 21 to 39 of the Rv1860 protein with the potential to distinguish latent TB infection from disease due to its ability to stimulate differential cytokine signatures in HV and PAT. We suggest that a TB vaccine carrying these and other CD8+T-cell-stimulating antigens has the potential to prevent progression of latentM. tuberculosisinfection to TB disease.

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Differential Regulation of Inflammatory Cytokine Secretion by Human Dendritic Cells upon Chlamydia trachomatis Infection

Infection and Immunity ◽

10.1128/iai.72.12.7231-7239.2004 ◽

2004 ◽

Vol 72 (12) ◽

pp. 7231-7239 ◽

Cited By ~ 57

Author(s):

Ana Gervassi ◽

Mark R. Alderson ◽

Robert Suchland ◽

Jean François Maisonneuve ◽

Kenneth H. Grabstein ◽

...

Keyword(s):

Dendritic Cells ◽

Chlamydia Trachomatis ◽

Wide Spectrum ◽

Cytokine Secretion ◽

Host Cells ◽

Microbial Pathogens ◽

Potential Contribution ◽

Necrosis Factor Alpha ◽

Chlamydia Trachomatis Infection ◽

Tnf Α

ABSTRACT Chlamydia trachomatis is an obligate intracellular gram-negative bacterium responsible for a wide spectrum of diseases in humans. Both genital and ocular C. trachomatis infections are associated with tissue inflammation and pathology. Dendritic cells (DC) play an important role in both innate and adaptive immune responses to microbial pathogens and are a source of inflammatory cytokines. To determine the potential contribution of DC to the inflammatory process, human DC were infected with C. trachomatis serovar E or L2. Both C. trachomatis serovars were found to infect and replicate in DC. Upon infection, DC up-regulated the expression of costimulatory (B7-1) and cell adhesion (ICAM-1) molecules. Furthermore, chlamydial infection induced the secretion of interleukin-1β (IL-1β), IL-6, IL-8, IL-12p70, IL-18, and tumor necrosis factor alpha (TNF-α). The mechanisms involved in Chlamydia-induced IL-1β and IL-18 secretion differed from those of the other cytokines. Chlamydia-induced IL-1β and IL-18 secretion required infection with viable bacteria and was associated with the Chlamydia-induced activation of caspase-1 in infected host cells. In contrast, TNF-α and IL-6 secretion did not require that the Chlamydia be viable, suggesting that there are at least two mechanisms involved in the Chlamydia-induced cytokine secretion in DC. Interestingly, an antibody to Toll-like receptor 4 inhibited Chlamydia-induced IL-1β, IL-6, and TNF-α secretion. The data herein demonstrate that DC can be infected by human C. trachomatis serovars and that chlamydial components regulate the secretion of various cytokines in DC. Collectively, these data suggest that DC play a role in the inflammatory processes caused by chlamydial infections.

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CD4+ CD25+ Foxp3+ Regulatory T Cells, Dendritic Cells, and Circulating Cytokines in Uncomplicated Malaria: Do Different Parasite Species Elicit Similar Host Responses?

Infection and Immunity ◽

10.1128/iai.00578-10 ◽

2010 ◽

Vol 78 (11) ◽

pp. 4763-4772 ◽

Cited By ~ 55

Author(s):

Raquel M. Gonçalves ◽

Karina C. Salmazi ◽

Bianca A. N. Santos ◽

Melissa S. Bastos ◽

Sandra C. Rocha ◽

...

Keyword(s):

Dendritic Cells ◽

Parasite Species ◽

Inflammatory Responses ◽

Clinical Symptoms ◽

Clinical Manifestations ◽

Surface Expression ◽

Interleukin 10 ◽

Treg Cells ◽

Experimental Models ◽

Necrosis Factor Alpha

ABSTRACT Clearing blood-stage malaria parasites without inducing major host pathology requires a finely tuned balance between pro- and anti-inflammatory responses. The interplay between regulatory T (Treg) cells and dendritic cells (DCs) is one of the key determinants of this balance. Although experimental models have revealed various patterns of Treg cell expansion, DC maturation, and cytokine production according to the infecting malaria parasite species, no studies have compared all of these parameters in human infections with Plasmodium falciparum and P. vivax in the same setting of endemicity. Here we show that during uncomplicated acute malaria, both species induced a significant expansion of CD4+ CD25+ Foxp3+ Treg cells expressing the key immunomodulatory molecule CTLA-4 and a significant increase in the proportion of DCs that were plasmacytoid (CD123+), with a decrease in the myeloid/plasmacytoid DC ratio. These changes were proportional to parasite loads but correlated neither with the intensity of clinical symptoms nor with circulating cytokine levels. One-third of P. vivax-infected patients, but no P. falciparum-infected subjects, showed impaired maturation of circulating DCs, with low surface expression of CD86. Although vivax malaria patients overall had a less inflammatory cytokine response, with a higher interleukin-10 (IL-10)/tumor necrosis factor alpha (TNF-α) ratio, this finding did not translate to milder clinical manifestations than those of falciparum malaria patients. We discuss the potential implications of these findings for species-specific pathogenesis and long-lasting protective immunity to malaria.

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Contrasting Function of Structured N-Terminal and Unstructured C-Terminal Segments of Mycobacterium tuberculosis PPE37 Protein

mBio ◽

10.1128/mbio.01712-17 ◽

2018 ◽

Vol 9 (1) ◽

Cited By ~ 16

Author(s):

Javeed Ahmad ◽

Aisha Farhana ◽

Rita Pancsa ◽

Simran Kaur Arora ◽

Alagiri Srinivasan ◽

...

Keyword(s):

Dendritic Cells ◽

Mycobacterium Tuberculosis ◽

Host Cell ◽

Terminal Segment ◽

Host Protein ◽

Host Cells ◽

Productive Infection ◽

Disordered Proteins ◽

Intrinsically Disordered

ABSTRACT Pathogens frequently employ eukaryotic linear motif (ELM)-rich intrinsically disordered proteins (IDPs) to perturb and hijack host cell networks for a productive infection. Mycobacterium tuberculosis has a relatively high percentage of IDPs in its proteome, the significance of which is not known. The Mycobacterium-specific PE-PPE protein family has several members with unusually high levels of structural disorder and disorder-promoting Ala/Gly residues. PPE37 protein, a member of this family, carries an N-terminal PPE domain capable of iron binding, two transmembrane domains, and a disordered C-terminal segment harboring ELMs and a eukaryotic nuclear localization signal (NLS). PPE37, expressed as a function of low iron stress, was cleaved by M. tuberculosis protease into N- and C-terminal segments. A recombinant N-terminal segment (P37N) caused proliferation and differentiation of monocytic THP-1 cells, into CD11c, DC-SIGN (dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin)-positive semimature dendritic cells exhibiting high interleukin-10 (IL-10) but negligible IL-12 and also low tumor necrosis factor alpha (TNF-α) secretion—an environment suitable for maintaining tolerogenic immune cells. The C-terminal segment entered the macrophage nucleus and induced caspase-3-dependent apoptosis of host cells. Mice immunized with recombinant PPE37FL and PPE37N evoked strong anti-inflammatory response, validating the in vitro immunostimulatory effect. Analysis of the IgG response of PPE37FL and PPE37N revealed significant immunoreactivities in different categories of TB patients, viz. pulmonary TB (PTB) and extrapulmonary TB (EPTB), vis-a-vis healthy controls. These results support the role of IDPs in performing contrasting activities to modulate the host processes, possibly through molecular mimicry and cross talk in two spatially distinct host environments which may likely aid M. tuberculosis survival and pathogenesis. IMPORTANCE To hijack the human host cell machinery to enable survival inside macrophages, the pathogen Mycobacterium tuberculosis requires a repertoire of proteins that can mimic host protein function and modulate host cell machinery. Here, we have shown how a single protein can play multiple functions and hijack the host cell for the benefit of the pathogen. Full-length membrane-anchored PPE37 protein is cleaved into N- and C-terminal domains under iron-depleted conditions. The N-terminal domain facilitates the propathogen semimature tolerogenic state of dendritic cells, whereas the C-terminal segment is localized into host cell nucleus and induces apoptosis. The immune implications of these in vitro observations were assessed and validated in mice and also human TB patients. This study presents novel mechanistic insight adopted by M. tuberculosis to survive inside host cells.

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A Candida albicans Mannoprotein Deprived of Its Mannan Moiety Is Efficiently Taken Up and Processed by Human Dendritic Cells and Induces T-Cell Activation without Stimulating Proinflammatory Cytokine Production

Infection and Immunity ◽

10.1128/iai.00669-08 ◽

2008 ◽

Vol 76 (9) ◽

pp. 4359-4367 ◽

Cited By ~ 21

Author(s):

Donatella Pietrella ◽

Patrizia Lupo ◽

Anna Rachini ◽

Silvia Sandini ◽

Alessandra Ciervo ◽

...

Keyword(s):

Dendritic Cells ◽

Candida Albicans ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Vaccine Candidate ◽

Pathogenic Fungi ◽

T Cell Response ◽

Necrosis Factor Alpha ◽

Recombinant Product

ABSTRACT Mannoproteins are cell wall components of pathogenic fungi and play major virulence and immunogenic roles with both their mannan and protein moieties. The 65-kDa mannoprotein (MP65) of Candida albicans is a β-glucanase adhesin recognized as a major target of the human immune response against this fungus, and its recombinant product (rMP65; devoid of the mannan moiety) is presently under consideration as a vaccine candidate. Here we investigated cellular and molecular aspects of the interaction of rMP65 with human antigen-presenting cells. We also assessed the ability of rMP65 to initiate a T-cell response. Both the native mannosylated MP65 (nMP65) and the recombinant product were efficiently bound and taken up by macrophages and dendritic cells. However, contrarily to nMP65, rMP65 did not induce tumor necrosis factor alpha and interleukin-6 release from these cells. On the other hand, rMP65 was rapidly endocytosed by both macrophages and dendritic cells, in a process involving both clathrin-dependent and clathrin-independent mechanisms. Moreover, the RGD sequence inhibited rMP65 uptake to some extent. After internalization, rMP65 partially colocalized with lysosomal membrane-associated glycoproteins 1 and 2. This possibly resulted in efficient protein degradation and presentation to CD4+ T cells, which proliferated and produced gamma interferon. Collectively, these results demonstrate that the absence of the mannan moiety does not deprive MP65 of the capacity to initiate the pattern of cellular and molecular events leading to antigen presentation and T-cell activation, which are essential features for further consideration of MP65 as a potential vaccine candidate.

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Extracellular Vesicles from Cryptococcus neoformans Modulate Macrophage Functions

Infection and Immunity ◽

10.1128/iai.01171-09 ◽

2010 ◽

Vol 78 (4) ◽

pp. 1601-1609 ◽

Cited By ~ 131

Author(s):

Débora L. Oliveira ◽

Célio G. Freire-de-Lima ◽

Joshua D. Nosanchuk ◽

Arturo Casadevall ◽

Marcio L. Rodrigues ◽

...

Keyword(s):

Cryptococcus Neoformans ◽

Extracellular Vesicles ◽

Transforming Growth Factor ◽

Transforming Growth Factor Β ◽

Interleukin 10 ◽

Biologically Active ◽

Host Cells ◽

Phagocytic Cells ◽

Necrosis Factor Alpha

ABSTRACT Cryptococcus neoformans and distantly related fungal species release extracellular vesicles that traverse the cell wall and contain a varied assortment of components, some of which have been associated with virulence. Previous studies have suggested that these extracellular vesicles are produced in vitro and during animal infection, but the role of vesicular secretion during the interaction of fungi with host cells remains unknown. In this report, we demonstrate by fluorescence microscopy that mammalian macrophages can incorporate extracellular vesicles produced by C. neoformans. Incubation of cryptococcal vesicles with murine macrophages resulted in increased levels of extracellular tumor necrosis factor alpha (TNF-α), interleukin-10 (IL-10), and transforming growth factor β (TGF-β). Vesicle preparations also resulted in a dose-dependent stimulation of nitric oxide production by phagocytes, suggesting that vesicle components stimulate macrophages to produce antimicrobial compounds. Treated macrophages were more effective at killing C. neoformans yeast. Our results indicate that the extracellular vesicles of C. neoformans can stimulate macrophage function, apparently activating these phagocytic cells to enhance their antimicrobial activity. These results establish that cryptococcal vesicles are biologically active.

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Stimulation of CD8+ T Cells following Diphtheria Toxin-Mediated Antigen Delivery into Dendritic Cells

Infection and Immunity ◽

10.1128/iai.74.2.1001-1008.2006 ◽

2006 ◽

Vol 74 (2) ◽

pp. 1001-1008 ◽

Cited By ~ 10

Author(s):

Christine A. Shaw ◽

Michael N. Starnbach

Keyword(s):

T Cells ◽

Dendritic Cells ◽

T Cell ◽

Targeted Delivery ◽

Diphtheria Toxin ◽

Mammalian Cells ◽

T Cell Response ◽

Host Cells ◽

Target Antigen ◽

Antigen Delivery

ABSTRACT Recognition and clearance of many intracellular pathogens requires the activation and subsequent effector functions of CD8+ T lymphocytes. To stimulate CD8+ T cells by immunization, the target antigens must be delivered into the cytosol of host cells. There they can be processed into peptides and presented in the context of major histocompatibility complex class I molecules to antigen-specific CD8+ T cells. One method of delivering antigens into the cytosol is to fuse them to modified bacterial toxins that are able to enter mammalian cells. The expression pattern of the toxin receptors in the host will determine the cell population that the toxin fusion protein targets and will thus restrict antigen-specific T-cell recognition to the same population. In this study we describe the development and characterization of a diphtheria toxin (DT)-based antigen delivery system. Using CD11c-DTR transgenic mice that express the DT receptor in dendritic cells (DC), this system allows for targeted delivery of CD8+ T-cell antigen to DC. We show that antigen-specific CD8+ T cells proliferate in CD11c-DTR mice following immunization with catalytically inactive DT-antigen fusion proteins. We also show that a toxin-based system that restricts antigen delivery to DC results in more robust antigen-specific CD8+ T-cell proliferation than a toxin-based system that does not restrict delivery to a particular cell type. These results have implications for vaccine design, and they suggest that use of a toxin-based vector to target antigen to DC may be an effective way to induce a CD8+ T-cell response.

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Cathepsins and Their Endogenous Inhibitors in Host Defense During Mycobacterium tuberculosis and HIV Infection

Frontiers in Immunology ◽

10.3389/fimmu.2021.726984 ◽

2021 ◽

Vol 12 ◽

Author(s):

Elsa Anes ◽

José Miguel Azevedo-Pereira ◽

David Pires

Keyword(s):

Mycobacterium Tuberculosis ◽

Bacterial Pathogen ◽

Hiv Infections ◽

Pathogen Transmission ◽

Host Cells ◽

Chronic Infections ◽

Host Immune Responses ◽

Endogenous Inhibitors ◽

Innovative Therapies ◽

The Moment

The moment a very old bacterial pathogen met a young virus from the 80’s defined the beginning of a tragic syndemic for humanity. Such is the case for the causative agent of tuberculosis and the human immunodeficiency virus (HIV). Syndemic is by definition a convergence of more than one disease resulting in magnification of their burden. Both pathogens work synergistically contributing to speed up the replication of each other. Mycobacterium tuberculosis (Mtb) and HIV infections are in the 21st century among the leaders of morbidity and mortality of humankind. There is an urgent need for development of new approaches for prevention, better diagnosis, and new therapies for both infections. Moreover, these approaches should consider Mtb and HIV as a co-infection, rather than just as separate problems, to prevent further aggravation of the HIV-TB syndemic. Both pathogens manipulate the host immune responses to establish chronic infections in intracellular niches of their host cells. This includes manipulation of host relevant antimicrobial proteases such as cathepsins or their endogenous inhibitors. Here we discuss recent understanding on how Mtb and HIV interact with cathepsins and their inhibitors in their multifactorial functions during the pathogenesis of both infections. Particularly we will address the role on pathogen transmission, during establishment of intracellular chronic niches and in granuloma clinical outcome and tuberculosis diagnosis. This area of research will open new avenues for the design of innovative therapies and diagnostic interventions so urgently needed to fight this threat to humanity.

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Factors Associated with Severe Granulomatous Pneumonia in Mycobacterium tuberculosis-Infected Mice Vaccinated Therapeutically with hsp65 DNA

Infection and Immunity ◽

10.1128/iai.73.8.5189-5193.2005 ◽

2005 ◽

Vol 73 (8) ◽

pp. 5189-5193 ◽

Cited By ~ 26

Author(s):

Jennifer L. Taylor ◽

Diane J. Ordway ◽

JoLynn Troudt ◽

Mercedes Gonzalez-Juarrero ◽

Randall J. Basaraba ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Ex Vivo ◽

Interleukin 10 ◽

Lung Pathology ◽

Necrosis Factor Alpha ◽

Cd8 Cells ◽

Factor Alpha ◽

Cell Gene ◽

Granulomatous Pneumonia ◽

Necrosis Factor

ABSTRACT Resistant C57BL/6 mice infected in the lungs with Mycobacterium tuberculosis and then therapeutically vaccinated with Mycobacterium leprae-derived hsp65 DNA develop severe granulomatous pneumonia and tissue damage. Analysis of cells accumulating in the lungs of these animals revealed substantial increases in T cells secreting tumor necrosis factor alpha and CD8 cells staining positive for granzyme B. Stimulation of lung cells ex vivo revealed very high levels of interleukin-10, some of which was produced by B-1 B cells. This was probably an anti-inflammatory response, since lung pathology was dramatically worsened in B-cell gene-disrupted mice.

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