scholarly journals Toxoplasma gondii Cyclophilin 18-Mediated Production of Nitric Oxide Induces Bradyzoite Conversion in a CCR5-Dependent Manner

2009 ◽  
Vol 77 (9) ◽  
pp. 3686-3695 ◽  
Author(s):  
Hany M. Ibrahim ◽  
Hiroshi Bannai ◽  
Xuenan Xuan ◽  
Yoshifumi Nishikawa
Keyword(s):  
Nitric Oxide ◽  
Toxoplasma Gondii ◽  
Inflammatory Responses ◽  
Interleukin 12 ◽  
Dependent Manner ◽  
Independent Manner ◽  
Necrosis Factor Alpha ◽  
Parasite Multiplication ◽  
Factor Alpha

ABSTRACT Toxoplasma gondii modulates pro- and anti-inflammatory responses to regulate parasite multiplication and host survival. Pressure from the immune response causes the conversion of tachyzoites into slowly dividing bradyzoites. The regulatory mechanisms involved in this switch are poorly understood. The aim of this study was to investigate the immunomodulatory role of T. gondii cyclophilin 18 (TgCyp18) in macrophages and the consequences of the cellular responses on the conversion machinery. Recombinant TgCyp18 induced the production of nitric oxide (NO), interleukin-12 (IL-12), and tumor necrosis factor alpha through its binding with cysteine-cysteine chemokine receptor 5 (CCR5) and the production of gamma interferon and IL-6 in a CCR5-independent manner. Interestingly, the treatment of macrophages with TgCyp18 resulted in the inhibition of parasite growth and an enhancement of the conversion into bradyzoites via NO in a CCR5-dependent manner. In conclusion, T. gondii possesses sophisticated mechanisms to manipulate host cell responses in a TgCyp18-mediated process.

scholarly journals Mannoproteins from Cryptococcus neoformans Promote Dendritic Cell Maturation and Activation

2005 ◽  
Vol 73 (2) ◽  
pp. 820-827 ◽  
Author(s):  
Donatella Pietrella ◽  
Cristina Corbucci ◽  
Stefano Perito ◽  
Giovanni Bistoni ◽  
Anna Vecchiarelli
Keyword(s):  
Cryptococcus Neoformans ◽  
Nuclear Factor Κb ◽  
Dendritic Cell Maturation ◽  
Interleukin 12 ◽  
Necrosis Factor Alpha ◽  
Histocompatibility Complex ◽  
Factor Alpha ◽  
Human Dendritic Cells ◽  
Mannose Receptors

ABSTRACT Our previous data show that mannoproteins (MPs) from Cryptococcus neoformans are able to induce protective responses against both C. neoformans and Candida albicans. Here we provide evidence that MPs foster maturation and activation of human dendritic cells (DCs). Maturation was evaluated by the ability of MPs to facilitate expression of costimulatory molecules such as CD40, CD86, CD83, and major histocompatibility complex classes I and II and to inhibit receptors such as CD14, CD16, and CD32. Activation of DCs was measured by the capacity of MPs to promote interleukin-12 and tumor necrosis factor alpha secretion. DC-induced maturation and interleukin-12 induction are largely mediated by engagement of mannose receptors and presume MP internalization and degradation. DC activation leads to IκBα phosphorylation, which is necessary for nuclear factor κB transmigration into the nucleus. MP-loaded DCs are efficient stimulators of T cells and show a remarkable capacity to promote CD4 and CD8 proliferation. In conclusion, we have evidenced a novel regulatory role of MPs that promotes their candidacy as a vaccine against fungi.

Role of nitric oxide in recombinant tumor necrosis factor-alpha-induced circulatory shock

1996 ◽  
Vol 24 (11) ◽  
pp. 1806-1810 ◽  
Author(s):  
Jan H. Zwaveling ◽  
Jan K. Maring ◽  
Han Moshage ◽  
Robert J. van Ginkel ◽  
Harald J. Hoekstra ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis Factor Alpha ◽  
Tumor Necrosis ◽  
Circulatory Shock ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Recombinant Tumor Necrosis Factor ◽  
Necrosis Factor

scholarly journals Toll-Like Receptor 9 Is Required for Full Host Resistance toMycobacteriumaviumInfection but Plays No Role in Induction of Th1 Responses

2011 ◽  
Vol 79 (4) ◽  
pp. 1638-1646 ◽  
Author(s):  
Natália B. Carvalho ◽  
Fernanda S. Oliveira ◽  
Fernanda V. Durães ◽  
Leonardo A. de Almeida ◽  
Manuela Flórido ◽  
...  
Keyword(s):  
Interleukin 12 ◽  
Toll Like Receptor ◽  
Necrosis Factor Alpha ◽  
Histocompatibility Complex ◽  
Tnf Α ◽  
Factor Alpha ◽  
Ifn Γ ◽  
Myd88 Signaling ◽  
Necrosis Factor

ABSTRACTTo investigate the role of Toll-like receptor 9 (TLR9) in innate immunity toMycobacteriumavium, TLR9, TLR2, and MyD88 knockout (KO) mice were infected with this bacterium. Bacterial burdens were higher in the spleens, livers, and lungs of infected TLR9 KO mice than in those of C57BL/6 mice, indicating that TLR9 is required for efficient control ofM.aviuminfection. However, TLR9 KO or TLR2 KO spleen cells displayed normalM.avium-induced tumor necrosis factor alpha (TNF-α) and gamma interferon (IFN-γ) responses. This finding was confirmed by determining the number of splenic CD4+T cells producing IFN-γ by flow cytometry. Furthermore, TLR2 and MyD88, but not TLR9, played a major role in interleukin-12 and TNF-α production byM.avium-infected macrophages and dendritic cells (DCs). We also found that major histocompatibility complex class II molecule expression on DCs is regulated by TLR2 and MyD88 signaling but not by TLR9. Finally, lack of TLR9, TLR2, or MyD88 reduced the numbers of macrophages, epithelioid cells, and lymphocytes inM.avium-induced granulomas but only MyD88 deficiency affected the number of liver granulomas. In summary, our data demonstrated that the involvement of TLR9 in the control ofM.aviuminfection is not related to the induction of Th1 responses.

scholarly journals In Vivo Regulation of Replicative Legionella pneumophila Lung Infection by Endogenous Interleukin-12

1998 ◽  
Vol 66 (1) ◽  
pp. 65-69 ◽  
Author(s):  
J. K. Brieland ◽  
D. G. Remick ◽  
M. L. LeGendre ◽  
N. C. Engleberg ◽  
J. C. Fantone
Keyword(s):  
Legionella Pneumophila ◽  
Lung Infection ◽  
Interleukin 12 ◽  
Necrosis Factor Alpha ◽  
Protein Levels ◽  
Tnf Α ◽  
Factor Alpha ◽  
Ifn Γ

ABSTRACT The in vivo role of endogenous interleukin 12 (IL-12) in modulating intrapulmonary growth of Legionella pneumophila was assessed by using a murine model of replicative L. pneumophila lung infection. Intratracheal inoculation of A/J mice with virulent bacteria (106 L. pneumophilacells per mouse) resulted in induction of IL-12, which preceded clearance of the bacteria from the lung. Inhibition of endogenous IL-12 activity, via administration of IL-12 neutralizing antiserum, resulted in enhanced intrapulmonary growth of the bacteria within 5 days postinfection (compared to untreated L. pneumophila-infected mice). Because IL-12 has previously been shown to modulate the expression of cytokines, including gamma interferon (IFN-γ), tumor necrosis factor alpha (TNF-α), and IL-10, which regulate L. pneumophila growth, immunomodulatory effects of endogenous IL-12 on intrapulmonary levels of these cytokines during replicative L. pneumophila lung infection were subsequently assessed. Results of these experiments demonstrated that TNF-α activity was significantly lower, while protein levels of IFN-γ and IL-10 in the lung were similar, in L. pneumophila-infected mice administered IL-12 antiserum, compared to similarly infected untreated mice. Together, these results demonstrate that IL-12 is critical for resolution of replicativeL. pneumophila lung infection and suggest that regulation of intrapulmonary growth of L. pneumophila by endogenous IL-12 is mediated, at least in part, by TNF-α.

scholarly journals Mechanism of Entry Determines the Ability of Toxoplasma gondii To Inhibit Macrophage Proinflammatory Cytokine Production

2002 ◽  
Vol 70 (9) ◽  
pp. 5216-5224 ◽  
Author(s):  
Barbara A. Butcher ◽  
Eric Y. Denkers
Keyword(s):  
Toxoplasma Gondii ◽  
Cytokine Production ◽  
Parasitophorous Vacuole ◽  
Interleukin 12 ◽  
Proinflammatory Cytokine Production ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Infected Cells ◽  
Factor Alpha ◽  
Necrosis Factor

ABSTRACT Macrophages (Mφ) infected with tachyzoites of the opportunistic protozoan Toxoplasma gondii are blocked in production of the proinflammatory cytokines tumor necrosis factor alpha (TNF-α) and interleukin-12 (IL-12) in response to lipopolysaccharide (LPS) triggering, and this is associated with parasite-induced inhibition of NFκB translocation. Here, we demonstrate a requirement for active invasion in the ability of the parasite to mediate suppression. Neither soluble tachyzoite antigen nor secreted products were suppressive, and heat-inactivated, antibody-coated tachyzoites, which efficiently entered the cell through receptor-mediated uptake, failed to inhibit LPS responses. Cytochalasin D, a drug blocking tachyzoite invasion of, but not adherence to, Mφ, severely curtailed Toxoplasma-induced suppression. In addition, parasite-induced nonresponsiveness, as measured by TNF-α production, was reversed by treating infected cells with the toxoplasmastatic drugs pyrimethamine and 6-thioxanthine prior to LPS stimulation. A divergence in IL-12 and TNF-α responses was found during extended incubation of tachyzoites and Mφ in that 24 h of incubation of infected Mφ resulted in IL-12, but not TNF-α, secretion, and production of the latter cytokine remained suppressed when these cells were subjected to LPS triggering. Our results demonstrate that active invasion and survival of the parasite within the parasitophorous vacuole are required to induce and maintain Mφ cytokine-specific nonresponsiveness to LPS. They also show that the effects of Toxoplasma on IL-12 and TNF-α production are nonidentical, with the parasite exerting a longer-lasting suppression of the latter.

scholarly journals Protection against Intestinal Amebiasis by a Recombinant Vaccine Is Transferable by T Cells and Mediated by Gamma Interferon

2009 ◽  
Vol 77 (9) ◽  
pp. 3909-3918 ◽  
Author(s):  
Xiaoti Guo ◽  
Lisa Barroso ◽  
Steven M. Becker ◽  
David M. Lyerly ◽  
Thomas S. Vedvick ◽  
...  
Keyword(s):  
T Cells ◽  
Gamma Interferon ◽  
Interleukin 12 ◽  
Necrosis Factor Alpha ◽  
Vaccine Protection ◽  
Adjuvant System ◽  
Factor Alpha ◽  
Ifn Γ ◽  
Intestinal Amebiasis

ABSTRACT We have previously shown that vaccination with purified Entamoeba histolytica Gal/GalNAc lectin or recombinant subunits can protect mice from intestinal amebiasis upon intracecal challenge. In this study, we demonstrated with adoptive-transfer experiments that this lectin vaccine protection is mediated by T cells but not serum. The cell-mediated immune (CMI) response was characterized by significant gamma interferon (IFN-γ), interleukin 12 (IL-12), IL-2, IL-10, and IL-17 production. To move toward a human vaccine, we switched to a recombinant protein and tested a range of adjuvants and routes appropriate for humans. We found that subcutaneous delivery of LecA with IDRI's adjuvant system EM014 elicited a potent Th1-type CMI profile and provided significant protection, as measured by culture negativity (79% efficacy); intranasal immunization with cholera toxin provided 56% efficacy; and alum induced a Th2-type response that protected 62 to 68% of mice. Several antibody and CMI cytokine responses were examined for correlates of protection, and prechallenge IFN-γ+ or IFN-γ-, IL-2-, and tumor necrosis factor alpha-triple-positive CD4 cells in blood were statistically associated with protection. To test the role of IFN-γ in LecA-mediated protection, we neutralized IFN-γ in LecA-immunized mice and found that it abrogated the protection conferred by vaccination. These data demonstrate that CMI is sufficient for vaccine protection from intestinal amebiasis and reveal an important role for IFN-γ, even in the setting of alum.

scholarly journals Macrophage Inflammatory Protein 1α/CCL3 Is Required for Clearance of an Acute Klebsiella pneumoniae Pulmonary Infection

2001 ◽  
Vol 69 (10) ◽  
pp. 6364-6369 ◽  
Author(s):  
Dennis M. Lindell ◽  
Theodore J. Standiford ◽  
Peter Mancuso ◽  
Zachary J. Leshen ◽  
Gary B. Huffnagle
Keyword(s):  
Klebsiella Pneumoniae ◽  
Alveolar Macrophages ◽  
Interleukin 12 ◽  
Necrosis Factor Alpha ◽  
Monocyte Chemoattractant Protein 1 ◽  
Inflammatory Protein ◽  
Cytokine Levels ◽  
Factor Alpha ◽  
Macrophage Inflammatory Protein

ABSTRACT The objective of these studies was to determine the role of macrophage inflammatory protein 1α/CCL3 in pulmonary host defense during Klebsiella pneumoniae infection. Following intratracheal inoculation, 7-day survival of CCL3−/− mice was less than 10%, compared to 60% for CCL3+/+ mice. Survival of CCR5−/− mice was equivalent to that of controls, indicating that the enhanced susceptibility of CCL3−/− mice to K. pneumoniae is mediated via another CCL3 receptor, presumably CCR1. At day 3, CFU burden in the lungs of CCL3−/− mice was 800-fold higher than in CCL3+/+ mice, demonstrating that CCL3 is critical for control of bacterial growth in the lung. Surprisingly, CCL3−/− mice had no differences in the recruitment of monocytes/macrophages and even showed enhanced neutrophil recruitment at days 1, 2, and 3 postinfection, compared to CCL3+/+ mice. Therefore, the defect in clearance was not due to insufficient recruitment of leukocytes. No significant differences in cytokine levels of monocyte chemoattractant protein 1 (MCP-1), interleukin 12, gamma interferon, or tumor necrosis factor alpha in lung lavages were found between CCL3+/+ and CCL3−/− mice. CCL3−/− alveolar macrophages were found to have significantly lower phagocytic activity toward K. pneumoniae than CCL3+/+alveolar macrophages. These findings demonstrate that CCL3 production is critical for activation of alveolar macrophages to control the pulmonary growth of the gram-negative bacterium K. pneumoniae.

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