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Determinants of GBP Recruitment to Toxoplasma gondii Vacuoles and the Parasitic Factors That Control It  [PDF]
Sebastian Virreira Winter, Wendy Niedelman, Kirk D. Jensen, Emily E. Rosowski, Lindsay Julien, Eric Spooner, Kacey Caradonna, Barbara A. Burleigh, Jeroen P. J. Saeij, Hidde L. Ploegh, Eva-Maria Frickel
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0024434
Abstract: IFN-γ is a major cytokine that mediates resistance against the intracellular parasite Toxoplasma gondii. The p65 guanylate-binding proteins (GBPs) are strongly induced by IFN-γ. We studied the behavior of murine GBP1 (mGBP1) upon infection with T. gondii in vitro and confirmed that IFN-γ-dependent re-localization of mGBP1 to the parasitophorous vacuole (PV) correlates with the virulence type of the parasite. We identified three parasitic factors, ROP16, ROP18, and GRA15 that determine strain-specific accumulation of mGBP1 on the PV. These highly polymorphic proteins are held responsible for a large part of the strain-specific differences in virulence. Therefore, our data suggest that virulence of T. gondii in animals may rely in part on recognition by GBPs. However, phagosomes or vacuoles containing Trypanosoma cruzi did not recruit mGBP1. Co-immunoprecipitation revealed mGBP2, mGBP4, and mGBP5 as binding partners of mGBP1. Indeed, mGBP2 and mGBP5 co-localize with mGBP1 in T. gondii-infected cells. T. gondii thus elicits a cell-autonomous immune response in mice with GBPs involved. Three parasitic virulence factors and unknown IFN-γ-dependent host factors regulate this complex process. Depending on the virulence of the strains involved, numerous GBPs are brought to the PV as part of a large, multimeric structure to combat T. gondii.
The Dysfunction of CD4+CD25+ Regulatory T Cells Contributes to the Abortion of Mice Caused by Toxoplasma gondii Excreted-Secreted Antigens in Early Pregnancy  [PDF]
Jin-ling Chen, Yi-yue Ge, Jie Zhang, Xiao-yan Qiu, Jing-fan Qiu, Jiang-ping Wu, Yong Wang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0069012
Abstract: Toxoplasma gondii is an opportunistic intracellular parasite that is highly prevalent in human and warm-blooded animals throughout the world, leading to potentially severe congenital infections. Although the abortion caused by T. gondii is believed to be dependent on the timing of maternal infection during pregnancy, the mechanism remains unclear. This study was focused on the effects of T. gondii excreted-secreted antigens on pregnant outcomes and CD4+CD25+ Foxp3+ regulatory T cells at different stages of pregnancy. The results showed that in mice the frequency and suppressive function of CD4+CD25+ regulatory cells were diminished after injection of T. gondii excreted-secreted antigens at early and intermediate stages of pregnancy. The abortion caused by T. gondii excreted-secreted antigens at early pregnancy could be partly prevented by adoptively transferring of CD4+CD25+ cells from the mice injected with T. gondii excreted-secreted antigens at late pregnancy, but not from the mice with the same treatment at early pregnancy. Furthermore, T. gondii excreted-secreted antigens induced apoptosis of CD4+CD25+ regulatory cells of mice in early and intermediate stages of pregnancy by down-regulating their Bcl-2 expressions and Bcl-2/Bax ratio. This study provides new insights into the mechanism that T. gondii infection is the high risk factor for abortion in early pregnancy.
Nazan Dalg??
Marmara Medical Journal , 2008,
Abstract: Pregnant women who acquire infection from Toxoplasma gondii usually remain asymptomatic, although they can still transmit the infection to their fetuses with severe consequences. Transmission of T. gondii to the fetus can result in serious health problems, including mental retardation, seizures, blindness, and death. Some health problems may not become apparent until the second or third decade of life. Serologic tests are used to diagnose acute T. gondii infection in pregnant women. Because false-positive tests occur frequently, serologic diagnosis must be confirmed at a Toxoplasma reference laboratory before treatment with potentially toxic drugs is considered. In many instances, congenital toxoplasmosis can be prevented by educating pregnant women and other women of childbearing age about not ingesting raw or undercooked meat, using measures to avoid cross-contamination of other foods with raw or undercooked meat, and protecting themselves against exposure to cat litter or contaminated soil.
Seroprevalence of Toxoplasma gondii in Pregnant Women  [PDF]
Servet K?lgelier,Hayati Demiraslan,Bekir Kata?,Dilek Güler
Dicle Medical Journal , 2009,
Abstract: T. gondii is a worldwide zoonosis. Children of women who acquire the infection during gestational period can develop congenital infection. In this study our aim was to determine the prevalence of Toxoplasma gondii in 455 pregnant women with an age range of 17-45 years. In this retrospective study, pregnant women applied to Obstetrics and Gynaecology Department of Ad yaman 82’nd Year State Hospital between January 2007 and December 2008 were evaluated in order to find the prevalence of anti-Toxoplasma gondii IgG and IgM antibodies. Seropositivity rates of anti-Toxoplasma gondii IgG and IgM antibodies were found to be 48.4% and 0.65%, respectively. In conclusion, due to the high seroprevalence rate of anti-T gondii antibodies we believe that taking measures related to the hygiene of the foods consumed and determining T. gondii serological markers of pregnant women in our region is essential.
The transcriptome of Toxoplasma gondii
Jay R Radke, Michael S Behnke, Aaron J Mackey, Josh B Radke, David S Roos, Michael W White
BMC Biology , 2005, DOI: 10.1186/1741-7007-3-26
Abstract: We have used serial analysis of gene expression (SAGE) to define the Toxoplasma gondii transcriptome of the intermediate-host life cycle that leads to the formation of the bradyzoite/tissue cyst. A broad view of gene expression is provided by >4-fold coverage from nine distinct libraries (~300,000 SAGE tags) representing key developmental transitions in primary parasite populations and in laboratory strains representing the three canonical genotypes. SAGE tags, and their corresponding mRNAs, were analyzed with respect to abundance, uniqueness, and antisense/sense polarity and chromosome distribution and developmental specificity.This study demonstrates that phenotypic transitions during parasite development were marked by unique stage-specific mRNAs that accounted for 18% of the total SAGE tags and varied from 1–5% of the tags in each developmental stage. We have also found that Toxoplasma mRNA pools have a unique parasite-specific composition with 1 in 5 transcripts encoding Apicomplexa-specific genes functioning in parasite invasion and transmission. Developmentally co-regulated genes were dispersed across all Toxoplasma chromosomes, as were tags representing each abundance class, and a variety of biochemical pathways indicating that trans-acting mechanisms likely control gene expression in this parasite. We observed distinct similarities in the specificity and expression levels of mRNAs in primary populations (Day-6 post-sporozoite infection) that occur prior to the onset of bradyzoite development that were uniquely shared with the virulent Type I-RH laboratory strain suggesting that development of RH may be arrested. By contrast, strains from Type II-Me49B7 and Type III-VEGmsj contain SAGE tags corresponding to bradyzoite genes, which suggests that priming of developmental expression likely plays a role in the greater capacity of these strains to complete bradyzoite development.Toxoplasma gondii belongs to the phylum Apicomplexa, which comprises a diverse group
First report of Toxoplasma gondii seroprevalence in peafowls in Yunnan Province, Southwestern China  [cached]
Tian Yi-Ming,Dai Fei-Yan,Huang Si-Yang,Deng Zu-Hong
Parasites & Vectors , 2012, DOI: 10.1186/1756-3305-5-205
Abstract: Background Toxoplasma gondii is an intracellular protozoan parasite infecting almost all warm-blooded animals, including birds, with a worldwide distribution. Surveys of T. gondii infection in wild birds have been reported extensively in the world, but little is known of T. gondii infection in peafowls worldwide. This study was performed to determine the seroprevalence of T. gondii infection in peafowls in Yunnan Province, southwestern China. Methods Sera from 277 peafowls, including 272 blue peafowls (Pavo cristatus) and 5 green peafowls (Pavo muticus) originated from two geographic areas in Yunnan Province were assayed for T. gondii antibodies using the modified agglutination test (MAT). Results Specific T. gondii antibodies were detected in 35 of 277 (12.64%) peafowls (MAT titer ≥ 1:5). Seropositive birds were found in both species, 33 in 272 blue peafowls and 2 in 5 green peafowls. There was no significant difference in T. gondii seroprevalence between the adolescent birds (6.74%) and the adult birds (6.67%) (P > 0.05). The geographical origins of peafowls was found to be highly associated with T. gondii infection in the present study, a statistically significant difference in T. gondii seropositivity was observed between peafowls from Kunming (31.08%) and those from Xishuangbanna Dai Autonomous Prefecture (5.91%) (OR = 10.956, 95% CI = 1.632-73.545, P = 0.014). Statistical analyses showed that there were no significant interactions between ages and geographical origins of peafowls (P > 0.05). Conclusions The results of the present survey indicated that infection of peafowls with T. gondii is widespread in Yunnan Province, which has significant public health concerns and implications for prevention and control of toxoplamosis in this province. To our knowledge, this is the first seroprevalence report of T. gondii infection in China’s southwestern Yunnan Province.
Toxoplasma gondii Infection in Stray Cats
H Hooshyar,P Rostamkhani,S Talari,M Arbabi
Iranian Journal of Parasitology , 2007,
Abstract: Background: Cat as definitive host of Toxoplasma gondii is important in the epidemiology of toxoplasmosis. The object of this study was to determine the seroprevalence of T. gondii as well as parasite isolation from faeces and brain tissues of stray cats in Kashan, central Iran. Methods: The prevalence of T. gondii was determined in serum, feces and brain tissue of 50 stray cats. IgG specific antibody to T. gondii was assessed by indirect fluorecent antibody test (IFAT). Results: Overall infection rate was 86% in 1:20 to1:640 titers. The highest percentage (22%) was for 1:160 and the least (6%) were for 1: 640. T. gondii tissue cyst isolated from 2(4%) cats by bioassay in mice. No oocysts detected from cat stool by direct and concentration methods. Conclusion: This study showed that the prevalence of T. gondii in stray cats is high in Kashan region.
Unusual Presentation of Toxoplasma Gondii Encephalitis  [cached]
Caleb Davis,Jacob Manteuffe
Western Journal of Emergency Medicine : Integrating Emergency Care with Population Health , 2012,
Abstract: We report a case of altered mental status secondary to acute Toxoplasma Gondii encephalitis. The patient had no medical or surgical history and presented with acute onset of lethargy with no clear precipitant. A physical exam revealed no focal neurological deficits and a subsequent medicalworkup revealed multiple intracranial lesions with a biopsy confirming the diagnosis of Toxoplasma Gondii encephalitis in the setting of newly diagnosed human immunodeficiency virus (HIV). A literature review revealed that this is a unique case of toxoplasmic encephalopathy in the United States in a previously undiagnosed HIV positive patient presenting to an emergency department.
Toxoplasma gondii infection in pregnancy
Lopes, Fabiana Maria Ruiz;Gon?alves, Daniela Dib;Mitsuka-Breganó, Regina;Freire, Roberta Lemos;Navarro, Italmar Teodorico;
Brazilian Journal of Infectious Diseases , 2007, DOI: 10.1590/S1413-86702007000500011
Abstract: toxoplasmosis is caused by an intracellular protozoan, toxoplasma gondii, which has a wide geographical distribution. the main infection routes are ingestion of cysts from raw or badly-cooked meat, ingestion of oocysts from substrates contaminated with the feces of infected felines and congenital transmission by tachyzoites. the congenital form results in a severe systemic disease, because if the mother is infected for the first time during gestation, she can present a temporary parasitemia that will infect the fetus. many of the clinical symptoms are seen in congenitally-infected children, from a mild disease to serious signs, such as mental retardation. early diagnosis during the pregnancy is highly desirable, allowing prompt intervention in cases of infection, through treatment of pregnant women, reducing the probability of fetal infection and consequent substantial damage to the fetus. conventional tests for establishment of a fetal diagnosis of toxoplasmosis include options from serology to pcr. prevention of human toxoplasmosis is based on care to avoid infection, understanding the disease and serological exams during gestation. pregnant women should be tested serologically from three months gestation, until one month after childbirth. inclusion of serology for congenital toxoplasmosis along with the basic guthrie test for pku is of fundamental importance for early diagnosis of infection and so that treatment is initiated, in order to avoid possible sequels in the infant.
Toxoplasma gondii Infection in Neonates
M Shaddel,ASA Mehbod,M Karamy
Iranian Journal of Parasitology , 2007,
Abstract: Background: To study toxoplasmosis in neonates using PCR and serological methods."nMethods: Sera and CSF of 104 neonates, hospitalized in infants' ward of Taleghani Hospital, Tehran, Iran were examined. The sera were examined for anti Toxoplasma gondii lgM and lgG specific antibodies with ELISA and IFA techniques, respectively. Meanwhile, obtained CSFs of the cases were evaluated for the genome of this parasite by PCR technique."nResults: Results showed positivity in 7 neonates (6.73%) which suggested congenital toxoplasmosis. Results of PCR were positive in 6 neonates (5.77%). The 1/100 titer of lgM specific antibodies was positive in 5(4.81%) of them by IFA technique and 6 neonates (5.77%) had positive results by ELISA technique for IgM specific. The rate of mortality was %0.96. Forty one neonates had 1/200 titer of specific lgG antibodies by IFA technique and 38 neonates had positive results by ELISA technique for IgG antibodies. The prevalence of chronic toxoplasmosis in mother was 32.7% and 30% by IFA and ELISA techniques, respectively. "nConclusion: Toxoplasmosis is still highly prevalent in neonates and should be considered due to the fact that suspected cases might be misdiagnosed and subsequently led to life- threatening or fatal condition.
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