scholarly journals Indoleamine 2,3-Dioxygenase Is Involved in Defense against Neospora caninum in Human and Bovine Cells

2009 ◽  
Vol 77 (10) ◽  
pp. 4496-4501 ◽  
Author(s):  
Katrin Spekker ◽  
Markus Czesla ◽  
Vanessa Ince ◽  
Kathrin Heseler ◽  
Silvia K. Schmidt ◽  
...  
Keyword(s):  
Neospora Caninum ◽  
Specific Inhibitor ◽  
Apicomplexan Parasite ◽  
Parasite Growth ◽  
Obligate Intracellular ◽  
Obligate Intracellular Parasite ◽  
Indoleamine 2,3 Dioxygenase ◽  
Cell Mediated Immune Response ◽  
Ifn Γ ◽  
Experimental Disease

ABSTRACT Neospora caninum is an apicomplexan parasite closely related to Toxoplasma gondii. In nature this parasite is found especially in dogs and cattle, but it may also infect other livestock. The growth of N. caninum, which is an obligate intracellular parasite, is controlled mainly by the cell-mediated immune response. During infection the cytokine gamma interferon (IFN-γ) plays a prominent role in regulating the growth of N. caninum in natural and experimental disease. The present study showed that induction of the tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO) is responsible for the inhibition of parasite growth that is mediated by IFN-γ-activated bovine fibroblasts and endothelial cells. This antiparasite effect could be abrogated by addition of tryptophan, as well as by the IDO-specific inhibitor 1-l-methyltryptophan. In conclusion, our data show that human and bovine cells use the same effector mechanism to control the growth of N. caninum.

scholarly journals Infected Dendritic Cells Facilitate Systemic Dissemination and Transplacental Passage of the Obligate Intracellular Parasite Neospora caninum in Mice

PLoS ONE ◽  
2012 ◽  
Vol 7 (3) ◽  
pp. e32123 ◽  
Author(s):  
Esther Collantes-Fernandez ◽  
Romanico B. G. Arrighi ◽  
Gema Álvarez-García ◽  
Jessica M. Weidner ◽  
Javier Regidor-Cerrillo ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Neospora Caninum ◽  
Intracellular Parasite ◽  
Transplacental Passage ◽  
Obligate Intracellular ◽  
Obligate Intracellular Parasite ◽  
Systemic Dissemination

scholarly journals Differential Regulation of Cathepsin S and Cathepsin L in Interferon γ–treated Macrophages

2003 ◽  
Vol 197 (2) ◽  
pp. 169-179 ◽  
Author(s):  
Courtney Beers ◽  
Karen Honey ◽  
Susan Fink ◽  
Katherine Forbush ◽  
Alexander Rudensky
Keyword(s):  
Cathepsin L ◽  
Specific Inhibitor ◽  
Cell Types ◽  
Interferon Γ ◽  
Cathepsin S ◽  
Antigen Presenting Cell ◽  
Relative Contribution ◽  
Helper Cell Type ◽  
Ifn Γ ◽  
Antigen Presenting

Cathepsin S (catS) and cathepsin L (catL) mediate late stages of invariant chain (Ii) degradation in discrete antigen-presenting cell types. Macrophages (Mϕs) are unique in that they express both proteases and here we sought to determine the relative contribution of each enzyme. We observe that catL plays no significant role in Ii cleavage in interferon (IFN)-γ–stimulated Mϕs. In addition, our studies show that the level of catL activity is significantly decreased in Mϕs cultured in the presence of IFN-γ whereas catS activity increases. The decrease in catL activity upon cytokine treatment occurs despite the persistence of high levels of mature catL protein, suggesting that a specific inhibitor of the enzyme is up-regulated in IFN-γ–stimulated peritoneal Mϕs. Similar inhibition of activity is observed in dendritic cells engineered to overexpress catL. Such enzymatic inhibition in Mϕs exhibits only partial dependence upon Ii and therefore, other mechanisms of catL inhibition are regulated by IFN-γ. Thus, during a T helper cell type 1 immune response catL inhibition in Mϕs results in preferential usage of catS, such that major histocompatibility complex class II presentation by all bone marrow–derived antigen-presenting cell is regulated by catS.

scholarly journals Upregulation of Cytokines Is Detected in the Placentas of Cattle Infected with Neospora caninum and Is More Marked Early in Gestation When Fetal Death Is Observed

2008 ◽  
Vol 76 (6) ◽  
pp. 2352-2361 ◽  
Author(s):  
Anne Rosbottom ◽  
E. Helen Gibney ◽  
Catherine S. Guy ◽  
Anja Kipar ◽  
Robert F. Smith ◽  
...  
Keyword(s):  
Protein Expression ◽  
Fetal Death ◽  
Neospora Caninum ◽  
Late Gestation ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mrna Levels ◽  
Cytokine Mrna ◽  
Early Gestation ◽  
Tnf Α ◽  
Ifn Γ

ABSTRACT The protozoan parasite Neospora caninum causes fetal death after experimental infection of pregnant cattle in early gestation, but the fetus survives a similar infection in late gestation. An increase in Th1-type cytokines in the placenta in response to the presence of the parasite has been implicated as a contributory factor to fetal death due to immune-mediated pathological alterations. We measured, using real-time reverse transcription-PCR and enzyme-linked immunosorbent assay, the levels of cytokines in the placentas of cattle experimentally infected with N. caninum in early and late gestation. After infection in early gestation, fetal death occurred, and the levels of mRNA of both Th1 and Th2 cytokines, including interleukin-2 (IL-2), gamma interferon (IFN-γ), IL-12p40, tumor necrosis factor alpha (TNF-α), IL-18, IL-10, and IL-4, were significantly (P < 0.01) increased by up to 1,000-fold. There was extensive placental necrosis and a corresponding infiltration of CD4+ T cells and macrophages. IFN-γ protein expression was also highly increased, and a modest increase in transforming growth factor β was detected. A much smaller increase in the same cytokines and IFN-γ protein expression, with minimal placental necrosis and inflammatory infiltration, occurred after N. caninum infection in late gestation when the fetuses survived. Comparison of cytokine mRNA levels in separated maternal and fetal placental tissue that showed maternal tissue was the major source of all cytokine mRNA except for IL-10 and TNF-α, which were similar in both maternal and fetal tissues. These results suggest that the magnitude of the cytokine response correlates with but is not necessarily the cause of fetal death and demonstrate that a polarized Th1 response was not evident in the placentas of N. caninum-infected cattle.

scholarly journals l-Arginine and Cationic Amino Acid Transporter 2B Regulate Growth and Survival of Leishmania amazonensis Amastigotes in Macrophages

2007 ◽  
Vol 75 (6) ◽  
pp. 2802-2810 ◽  
Author(s):  
Nanchaya Wanasen ◽  
Carol L. MacLeod ◽  
Lesley G. Ellies ◽  
Lynn Soong
Keyword(s):  
Amino Acid ◽  
Amino Acid Transporter ◽  
Parasite Growth ◽  
Leishmania Amazonensis ◽  
Growth Enhancement ◽  
Cationic Amino Acid Transporter ◽  
Cationic Amino Acid ◽  
Arginine Transport ◽  
Ifn Γ ◽  
Acid Transporter

ABSTRACT Leishmania spp. are obligate intracellular parasites, requiring a suitable microenvironment for their growth within host cells. We previously reported that the growth of Leishmania amazonensis amastigotes in murine macrophages (Mφs) was enhanced in the presence of gamma interferon (IFN-γ), a Th1 cytokine normally associated with classical Mφ activation and killing of intracellular pathogens. In this study, we provided several lines of evidence suggesting that IFN-γ-mediated parasite growth enhancement was associated with l-arginine transport via mouse cationic amino acid transporter 2B (mCAT-2B). (i) mRNA expression of Slc7A2, the gene encoding for mCAT-2B, as well as l-arginine transport was increased in IFN-γ-treated Mφs. (ii) Supplementation of l-arginine in Mφ cultures increased parasite growth. (iii) Parasite growth enhancement in wild-type Mφs was inhibited in the presence of nonmetabolized l-arginine analogues. (iv) IFN-γ-mediated parasite growth was absent in Mφs derived from mCAT-2B-deficient mice. Although we detected a clear upregulation of mCAT-2B and l-arginine transport, no measurable iNOS or arginase activities were observed in IFN-γ-treated, infected Mφs. Together, these data suggest an involvement of a novel l-arginine usage independent of iNOS and arginase activities during IFN-γ-mediated parasite growth enhancement. A possible role of mCAT-2B in supplying l-arginine directly to the parasites for their proliferation is discussed.

scholarly journals Influence of host reproductive state onSphaerothecum destruensprevalence and infection level

Parasitology ◽  
2010 ◽  
Vol 138 (1) ◽  
pp. 26-34 ◽  
Author(s):  
D. ANDREOU ◽  
M. HUSSEY ◽  
S. W. GRIFFITHS ◽  
R. E. GOZLAN
Keyword(s):  
Detection Limit ◽  
Real Time ◽  
Genomic Dna ◽  
Adverse Impact ◽  
Intracellular Parasite ◽  
Reproductive State ◽  
Chain Reaction ◽  
Infection Level ◽  
Obligate Intracellular ◽  
Obligate Intracellular Parasite

SUMMARYSphaerothecum destruensis an obligate intracellular parasite with the potential to cause high mortalities and spawning inhibition in the endangered cyprinidLeucaspius delineatus. We investigated the influence ofL. delineatus’s reproductive state on the prevalence and infection level ofS. destruens. A novel real time quantitative polymerarse chain reaction (qPCR) was developed to determineS. destruens’ prevalence and infection level. These parameters were quantified and compared in reproductive and non-reproductiveL. delineatus. The detection limit of theS. destruensspecific qPCR was determined to be 1 pg of purifiedS. destruensgenomic DNA. Following cohabitation in the lab, reproductiveL. delineatushad a significantly higherS. destruensprevalence (P<0·05) and infection levels (P<0·01) compared to non-reproductiveL. delineatus. S. destruensprevalence was 19% (n=40) in non-reproductiveL. delineatusand 41% (n=32) in reproductiveL. delineatus. However, there was no difference inS. destruensprevalence in reproductive and non-reproductive fish under field conditions. Mean infection levels were 18 and 99 pgS. destruensDNA per 250 ngL. delineatusDNA for non-reproductive and reproductiveL. delineatusrespectively. The present work indicates thatS. destruensinfection inL. delineatuscan be influenced by the latter's reproductive state and provides further support for the potential adverse impact ofS. destruenson the conservation ofL. delineatuspopulations.

scholarly journals IFN-γ Amplifies IL-6 and IL-8 Responses by Airway Epithelial-Like Cells Via Indoleamine 2,3-Dioxygenase

2002 ◽  
Vol 169 (12) ◽  
pp. 7039-7044 ◽  
Author(s):  
Matthijs van Wissen ◽  
Mieke Snoek ◽  
Barbara Smids ◽  
Henk M. Jansen ◽  
René Lutter
Keyword(s):  
Airway Epithelial ◽  
Indoleamine 2,3 Dioxygenase ◽  
Ifn Γ

scholarly journals Toxoplasma gondii Rhoptry Discharge Correlates with Activation of the Early Growth Response 2 Host Cell Transcription Factor

2008 ◽  
Vol 76 (10) ◽  
pp. 4703-4712 ◽  
Author(s):  
Eric D. Phelps ◽  
Kristin R. Sweeney ◽  
Ira J. Blader
Keyword(s):  
Transcription Factor ◽  
Toxoplasma Gondii ◽  
Host Cell ◽  
Growth Response ◽  
Neospora Caninum ◽  
Early Growth ◽  
Apicomplexan Parasite ◽  
Host Cells ◽  
Early Growth Response ◽  
Cell Extracts

ABSTRACT Toxoplasma gondii is a ubiquitous apicomplexan parasite that can cause severe disease in fetuses and immune-compromised patients. Rhoptries, micronemes, and dense granules, which are secretory organelles unique to Toxoplasma and other apicomplexan parasites, play critical roles in parasite growth and virulence. To understand how these organelles modulate infected host cells, we sought to identify host cell transcription factors triggered by their release. Early growth response 2 (EGR2) is a host cell transcription factor that is rapidly upregulated and activated in Toxoplasma-infected cells but not in cells infected with the closely related apicomplexan parasite Neospora caninum. EGR2 upregulation occurred only when live parasites were in direct contact with the host cell and not from exposure to cell extracts that contain dense granule or micronemal proteins. When microneme-mediated attachment was blocked by pretreating parasites with a calcium chelator, EGR2 expression was significantly reduced. In contrast, when host cells were infected with parasites in the presence of cytochalasin D, which allows rhoptry secretion but prevents parasite invasion, EGR2 was activated. Finally, we demonstrate that Toxoplasma activation of host p38 mitogen-activated protein kinase is necessary but not sufficient for EGR2 activation. Collectively, these data indicate that EGR2 is specifically upregulated by a parasite-derived secreted factor that is most likely a resident rhoptry protein.

Invasion of Toxoplasma gondii occurs by active penetration of the host cell

1995 ◽  
Vol 108 (6) ◽  
pp. 2457-2464 ◽  
Author(s):  
J.H. Morisaki ◽  
J.E. Heuser ◽  
L.D. Sibley
Keyword(s):  
Toxoplasma Gondii ◽  
Host Cell ◽  
Tyrosine Phosphorylation ◽  
Host Cells ◽  
The Novel ◽  
Host Proteins ◽  
Host Cell Membrane ◽  
Membrane Ruffling ◽  
Obligate Intracellular ◽  
Obligate Intracellular Parasite

Toxoplasma gondii is an obligate intracellular parasite that infects a wide variety of vertebrate cells including macrophages. We have used a combination of video microscopy and fluorescence localization to examine the entry of Toxoplasma into macrophages and nonphagocytic host cells. Toxoplasma actively invaded host cells without inducing host cell membrane ruffling, actin microfilament reorganization, or tyrosine phosphorylation of host proteins. Invasion occurred rapidly and within 25–40 seconds the parasite penetrated into a tight-fitting vacuole formed by invagination of the plasma membrane. In contrast, during phagocytosis of Toxoplasma, extensive membrane ruffling captured the parasite in a loose-fitting phagosome that formed over a period of 2–4 minutes. Phagocytosis involved both reorganization of the host cytoskeleton and tyrosine phosphorylation of host proteins. In some cases, parasites that were first internalized by phagocytosis, were able to escape from the phagosome by a process analogous to invasion. These studies reveal that active penetration of the host cell by Toxoplasma is fundamentally different from phagocytosis or induced endocytic uptake. The novel ability to penetrate the host cell likely contributes to the capability of Toxoplasma-containing vacuoles to avoid endocytic processing.

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