scholarly journals The role of anti-HSP70 autoantibody-forming VH1-JH1 B-1 cells in Toxoplasma gondii-infected mice

2003 ◽  
Vol 15 (1) ◽  
pp. 39-47 ◽  
Author(s):  
M. Chen
Keyword(s):  
Toxoplasma Gondii

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 Interleukin-17/Interleukin-17 Receptor-Mediated Signaling Is Important for Generation of an Optimal Polymorphonuclear Response against Toxoplasma gondii Infection

2005 ◽  
Vol 73 (1) ◽  
pp. 617-621 ◽  
Author(s):  
Michelle N. Kelly ◽  
Jay K. Kolls ◽  
Kyle Happel ◽  
Joseph D. Schwartzman ◽  
Paul Schwarzenberger ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Adaptive Immunity ◽  
Protective Immunity ◽  
Polymorphonuclear Leukocytes ◽  
Early Infection ◽  
Interleukin 17 ◽  
Toxoplasma Gondii Infection ◽  
Knockout Animals

ABSTRACT We investigated the role of interleukin-17 (IL-17)/IL-17 receptor (IL-17R)-mediated signaling in the protective immunity against Toxoplasma gondii. IL-17R−/− mice developed a normal adaptive immunity against the parasite. However, increased mortality in the knockout animals can be attributed to a defect in the migration of polymorphonuclear leukocytes to infected sites during early infection.

scholarly journals The antioxidant systems in Toxoplasma gondii and the role of cytosolic catalase in defence against oxidative injury

2003 ◽  
Vol 51 (1) ◽  
pp. 47-61 ◽  
Author(s):  
Lai Yu Kwok ◽  
Dirk Schlüter ◽  
Christine Clayton ◽  
Dominique Soldati
Keyword(s):  
Toxoplasma Gondii ◽  
Oxidative Injury ◽  
Antioxidant Systems

Is Toxoplasma gondii Infection a Cause or a Coincidence in an Adolescent with Psychosis?

2020 ◽  
Author(s):  
Hüsniye Yucel ◽  
Burak Acikel ◽  
F Nur Öz ◽  
Saliha Senel
Keyword(s):  
Toxoplasma Gondii ◽  
Psychiatric Symptoms ◽  
Current Level ◽  
Neuropsychiatric Diseases ◽  
New Knowledge ◽  
Young Adolescent Girl ◽  
Toxoplasma Gondii Infection ◽  
Psychiatric Problems ◽  
Immunocompetent Patients

AbstractAlthough presumed to be relatively harmless in immunocompetent patients, toxoplasmosis has been linked to several psychiatric problems such as schizophrenia, bipolar disorder, and suicidal/aggressive behaviors. We describe an 11-year-old young adolescent girl with psychoses who was ultimately diagnosed with toxoplasmosis. It is an unusual presentation of Toxoplasma gondii infection that adds new knowledge to the current level of literature about the substantial role of Toxoplasma gondii in the etiology of neuropsychiatric diseases. We propose that screening for toxoplasmosis is needed besides other etiologies in differential diagnosis of psychiatric symptoms particularly in endemic areas.

Role of Macrophage-Derived Cytokines in the Induction and Regulation of Cell-Mediated Immunity to Toxoplasma gondii

1996 ◽  
pp. 127-139 ◽  
Author(s):  
R. T. Gazzinelli ◽  
D. Amichay ◽  
T. Sharton-Kersten ◽  
E. Grunwald ◽  
J. M. Farber ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Cell Mediated Immunity

scholarly journals Toxoplasma gondii GRA9 Regulates the Activation of NLRP3 Inflammasome to Exert Anti-Septic Effects in Mice

2020 ◽  
Vol 21 (22) ◽  
pp. 8437
Author(s):  
Jae-Sung Kim ◽  
Seok-Jun Mun ◽  
Euni Cho ◽  
Donggyu Kim ◽  
Wooic Son ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Nlrp3 Inflammasome ◽  
Dense Granule ◽  
E Coli ◽  
Pyrin Domain ◽  
Essential Components ◽  
Bactericidal Effects ◽  
Anti Inflammatory

Dense granule proteins (GRAs) are essential components in Toxoplasma gondii, which are suggested to be promising serodiagnostic markers in toxoplasmosis. In this study, we investigated the function of GRA9 in host response and the associated regulatory mechanism, which were unknown. We found that GRA9 interacts with NLR family pyrin domain containing 3 (NLRP3) involved in inflammation by forming the NLRP3 inflammasome. The C-terminal of GRA9 (GRA9C) is essential for GRA9–NLRP3 interaction by disrupting the NLRP3 inflammasome through blocking the binding of apoptotic speck-containing (ASC)-NLRP3. Notably, Q200 of GRA9C is essential for the interaction of NLRP3 and blocking the conjugation of ASC. Recombinant GRA9C (rGRA9C) showed an anti-inflammatory effect and the elimination of bacteria by converting M1 to M2 macrophages. In vivo, rGRA9C increased the anti-inflammatory and bactericidal effects and subsequent anti-septic activity in CLP- and E. coli- or P. aeruginosa-induced sepsis model mice by increasing M2 polarization. Taken together, our findings defined a role of T. gondii GRA9 associated with NLRP3 in host macrophages, suggesting its potential as a new candidate therapeutic agent for sepsis.

scholarly journals Role of Toxoplasma gondii Chloroquine Resistance Transporter in Bradyzoite Viability and Digestive Vacuole Maintenance

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Geetha Kannan ◽  
Manlio Di Cristina ◽  
Aric J. Schultz ◽  
My-Hang Huynh ◽  
Fengrong Wang ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Chronic Infection ◽  
Chloroquine Resistance ◽  
Congenital Defects ◽  
Functional Link ◽  
Content Type ◽  
Chloroquine Resistance Transporter

ABSTRACT Toxoplasma gondii is a ubiquitous pathogen that can cause encephalitis, congenital defects, and ocular disease. T. gondii has also been implicated as a risk factor for mental illness in humans. The parasite persists in the brain as slow-growing bradyzoites contained within intracellular cysts. No treatments exist to eliminate this form of parasite. Although proteolytic degradation within the parasite lysosome-like vacuolar compartment (VAC) is critical for bradyzoite viability, whether other aspects of the VAC are important for parasite persistence remains unknown. An ortholog of Plasmodium falciparum chloroquine resistance transporter (CRT), TgCRT, has previously been identified in T. gondii. To interrogate the function of TgCRT in chronic-stage bradyzoites and its role in persistence, we knocked out TgCRT in a cystogenic strain and assessed VAC size, VAC digestion of host-derived proteins and parasite autophagosomes, and the viability of in vitro and in vivo bradyzoites. We found that whereas parasites deficient in TgCRT exhibit normal digestion within the VAC, they display a markedly distended VAC and their viability is compromised both in vitro and in vivo. Interestingly, impairing VAC proteolysis in TgCRT-deficient bradyzoites restored VAC size, consistent with a role for TgCRT as a transporter of products of digestion from the VAC. In conjunction with earlier studies, our current findings suggest a functional link between TgCRT and VAC proteolysis. This study provides further evidence of a crucial role for the VAC in bradyzoite persistence and a new potential VAC target to abate chronic Toxoplasma infection. IMPORTANCE Individuals chronically infected with the intracellular parasite Toxoplasma gondii are at risk of experiencing reactivated disease that can result in progressive loss of vision. No effective treatments exist for chronic toxoplasmosis due in part to a poor understanding of the biology underlying chronic infection and a lack of well-validated potential targets. We show here that a T. gondii transporter is functionally linked to protein digestion within the parasite lysosome-like organelle and that this transporter is necessary to sustain chronic infection in culture and in experimentally infected mice. Ablating the transporter results in severe bloating of the lysosome-like organelle. Together with earlier work, this study suggests the parasite’s lysosome-like organelle is vital for parasite survival, thus rendering it a potential target for diminishing infection and reducing the risk of reactivated disease.

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