Listeria monocytogenes protein fraction induces dendritic cells maturation and T helper 1 immune responses (original) (raw)
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Production of IL-12 and IL-18 in human dendritic cells upon infection by Listeria monocytogenes
FEMS Immunology & Medical Microbiology, 2003
Dendritic cells (DCs) are major antigen-presenting cells of the immune system, which need to be activated in order to initiate an immune response. Here, we describe the immunostimulatory effects on human monocyte-derived DCs observed upon infection with Listeria monocytogenes or after treatment with listerial lipoteichoic acid (LTA) and lipopolysaccharide (LPS), respectively. All stimuli caused upregulation of costimulatory molecules, induced T-cell proliferative responses and secretion of cytokines in vitro. Infection of DCs with L. monocytogenes induced release of interleukin (IL)-12 and IL-18. In contrast treatment with purified listerial LTA yielded high levels of IL-18 release, but only minimal IL-12 production. Treatment of DCs with LPS conversely induced significant amounts of IL-12 production, but no IL-18. The release of both stimulating cytokines IL-12 and IL-18 upon infection with entire bacteria suggests that attenuated strains of L. monocytogenes may be a valuable tool for subunit vaccine delivery.
Listeria monocytogenes-Infected Human Dendritic Cells: Uptake and Host Cell Response
Infection and Immunity, 2000
of specific immune responses. Various pathogens are able to persist inside DCs. However, internalization of the gram-positive bacterium Listeria monocytogenes into human DCs has not yet been shown. In the present study, we demonstrate that human monocyte-derived immature DCs can efficiently phagocytose L. monocytogenes. This uptake is independent of listerial adhesion factors internalin A and internalin B but requires cytoskeletal motion and factors present in human plasma. A major portion of internalized bacteria is found in membranebound phagosomes and is rarely free in the cytosol, as shown by transmission electron microscopy and by using an L. monocytogenes strain expressing green fluorescent protein when in the host cell cytosol. The infection caused maturation of the immature DCs into mature DCs displaying high levels of CD83, CD25, major histocompatibility complex class II, and the CD86 costimulator molecule. This effect appeared to be largely mediated by listerial lipoteichoic acid. Although L. monocytogenes infection is known to induce death in other cell types, infection of human DCs was found to induce necrotic but not apoptotic death in fewer than 20% of DCs. Therefore, the ability of DCs to act as effective antigen-presenting cells for listerial immunity is probably enhanced by their resistance to cell death, as well as their ability to rapidly differentiate into mature, immunostimulatory DCs upon encountering bacteria.
Infection and Immunity, 2003
Splenic dendritic cells (DCs) obtained from mice at 48 h after Listeria monocytogenes infection exhibited up-regulation of CD80 and produced higher titers of gamma interferon (IFN-␥) and interleukin-12 (IL-12) than did DCs obtained from uninfected mice. Mice immunized with DCs obtained from mice that had been infected with L. monocytogenes 48 h before acquired host resistance to lethal infection with L. monocytogenes at 4 and 8 weeks. Immunization with DCs from heat-killed L. monocytogenes failed to induce resistance. Acquired antilisterial resistance is specific, since the immunized mice could not be protected from Salmonella enterica serovar Typhimurium infection. Infected DCs stimulated proliferation of naive CD4 ؉ and CD8 ؉ cells in vitro, suggesting that in vivo-infected DCs activate CD8 ؉ T cells, which are critical in acquired antilisterial resistance, as well as CD4 ؉ T cells. When wild-type mice were immunized with DCs from IFN-␥-deficient mice, they were protected against a lethal L. monocytogenes challenge. In contrast, when mice were immunized with DCs from anti-IL-12 p40 monoclonal antibody-injected mice, they failed to gain acquired antilisterial resistance. These results suggest that DC-derived IL-12, but not IFN-␥, may play a critical role in induction of acquired antilisterial resistance. Our present results suggest that splenic DCs obtained from mice infected with L. monocytogenes in vivo may be an effective immunogen with which to induce antigen-specific immunity.
Listeria-Infected Myeloid Dendritic Cells Produce IFN- , Priming T Cell Activation
The Journal of Immunology, 2005
The intracellular bacterium Listeria monocytogenes infects dendritic cells (DC) and other APCs and induces potent cell-mediated protective immunity. However, heat-killed bacteria fail to do so. This study explored whether DC differentially respond to live and killed Listeria and how this affects T cell activation. To control for bacterial number, a replication-deficient strain, Lmdd, defective in D-alanine biosynthesis, was used. We found that DC internalize both live and heat-killed Lmdd and similarly up-regulate the expression of costimulatory molecules, a necessary step for T cell activation. However, only live Lmdd-infected DC stimulate T cells to express the early activation marker CD69 and enhance T cell activation upon TCR engagement. Infection with live, but not heat-killed, Lmdd induces myeloid DC to secrete copious amounts of IFN-, which requires bacterial cytosolic invasion. Exposure to high concentrations of IFN- sensitizes naive T cells for Ag-dependent activation.
PLoS ONE, 2011
During the course of a microbial infection, different antigen presenting cells (APCs) are exposed and contribute to the ensuing immune response. CD8a + dendritic cells (DCs) are an important coordinator of early immune responses to the intracellular bacteria Listeria monocytogenes (Lm) and are crucial for CD8 + T cell immunity. In this study, we examine the contribution of different primary APCs to inducing immune responses against Lm. We find that CD8a + DCs are the most susceptible to infection while plasmacytoid DCs are not infected. Moreover, CD8a + DCs are the only DC subset capable of priming an immune response to Lm in vitro and are also the only APC studied that do so when transferred into b2 microglobulin deficient mice which lack endogenous cross-presentation. Upon infection, CD11b + DCs primarily secrete low levels of TNFa while CD8a + DCs secrete IL-12 p70. Infected monocytes secrete high levels of TNFa and IL-12p70, cytokines associated with activated inflammatory macrophages. Furthermore, co-culture of infected CD8a + DCs and CD11b+ DCs with monocytes enhances production of IL-12 p70 and TNFa. However, the presence of monocytes in DC/T cell co-cultures attenuates T cell priming against Lm-derived antigens in vitro and in vivo. This suppressive activity of spleen-derived monocytes is mediated in part by both TNFa and inducible nitric oxide synthase (iNOS). Thus these monocytes enhance IL-12 production to Lm infection, but concurrently abrogate DC-mediated T cell priming.
The Journal of Immunology, 2008
Myeloid dendritic cells (DC) and macrophages play an important role in pathogen sensing and antimicrobial defense. In this study we provide evidence that myeloid DC respond to infection with Listeria monocytogenes with simultaneous induction of multiple stimulatory and inhibitory molecules. However, the overall impact of infected DC during T cell encounter results in suppression of T cell activation, indicating that inhibitory pathways functionally predominate. Inhibitory activity of infected DC is effected mainly by IL-10 and cyclooxygenase 2-mediated mechanisms, with soluble CD25 acting as an IL-2 scavenger as well as by the products of tryptophan catabolism. These inhibitory pathways are strictly TNF-dependent.
Iranian Journal of Immunology Iji, 2008
The use of dendritic cells (DCs) as a cellular adjuvant provides a promising approach in immunotherapy of cancer. It has been demonstrated that Listeria monocytogenes activated DCs pulsed ex vivo with tumor antigens trigger a systemic Th1biased specific immune response and a single dose of this vaccine will cause a considerable anti tumor immunity. Objective: The present study was designed to evaluate the ability of multiple doses of tumor antigen-pulsed DCs, matured in the presence of Listeria monocytogenes components in induction of a potent anti-tumor response and the prevention of tumor formation in an experimental model. Methods: Bone-marrow derived DCs (BMDCs) were cultured in the presence of GM-CSF and IL-4. After 5 days, tumor lysates with/without Listeria monocytogenes lysate were added to the culture media for another 2 days. Mice received mature and tumor antigen pulsed dendritic cells subcutaneously in 3 groups. Tumor growth was monitored and two weeks after immunotherapy, cytotoxic activity of CD8+ T cells was evaluated in different groups. Results: According to the findings, repeated doses of vaccine did not lead to a significant increase in the activity of cytotoxic T cells and decreased tumor growth of immunized animals. Conclusion: The current study suggests that increased doses of vaccine do not have sufficient efficiency for prevention of tumor induction. Generation of T regulatory responses upon repeated doses of such vaccines should be considered in future investigations.
Iranian journal of allergy, asthma, and immunology, 2015
The innate immune system utilizes pattern recognition receptors (PRRs) to recognize microbes. Pathogens contain various molecules with diverse effects on immune response. In this study, we evaluated the effect of DNA and protein components derived from two intracellular microorganisms including Listeria monocytogenes (L. monocytogenes) and Toxoplasma gondii (T. gondii) on dendritic cells (DCs) activation and ensuing adaptive immune responses. DNA and protein components of L. monocytogenes and T. gondii were prepared using relevant kits. DNA and protein components of these two pathogens were added to immature DCs (iDCs). Subsequently, co-stimulatory expression and cytokine production by DCs were measured. Finally, we evaluated the stimulatory capacity of mature DCs (mDCs) in DC-T cells co-culture. The results showed that protein matured-DCs produced higher level of IL (Interleukin)-12p70. There was also a significant increase in Interferon-Gamma (IFN-γ) production and proliferative c...
PLoS pathogens, 2016
Infection by Listeria monocytogenes (Lm) causes serious sepsis and meningitis leading to mortality in neonates. This work explored the ability of CD11chigh lineage DCs to induce CD8+ T-cell immune protection against Lm in mice before 7 days of life, a period symbolized by the absence of murine IL-12p70-producing CD11chighCD8α+ dendritic cells (DCs). We characterized a dominant functional Batf3-dependent precursor of CD11chigh DCs that is Clec9A+CD205+CD24+ but CD8α- at 3 days of life. After Lm-OVA infection, these pre-DCs that cross-present Ag display the unique ability to produce high levels of IL-12p40 (not IL-12p70 nor IL-23), which enhances OVA-specific CD8+ T cell response, and regulatory IL-10 that limits OVA-specific CD8+ T cell response. Targeting these neonatal pre-DCs for the first time with a single treatment of anti-Clec9A-OVA antibody in combination with a DC activating agent such as poly(I:C) increased the protection against later exposure to the Lm-OVA strain. Poly(I:...