GRA Proteins of Toxoplasma gondii: Maintenance of Host-Parasite Interactions across the Parasitophorous Vacuolar Membrane

Nam, Ho-Woo

doi:10.3347/kjp.2009.47.s.s29

Cited by 90 publications

(75 citation statements)

References 76 publications

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“…The greater expression of GRA 2, 3, and 6 and UPRTase found in the KI-1 tachyzoites confirm previous reports showing that the KI-1 tachyzoite is a virulent local isolate [7]. Dense granule protein expression was higher in the KI-1 tachyzoites than in the RH tachyzoites; T. gondii GRAs may participate in the modification of parasitophorous vacuoles (PVs) and the PV membrane, which are required for the maintenance of intracellular parasitism in almost all nucleated host cells [17]. GRA 1-5, 7, and 8; microneme protein 5; NTPase-I; catalase; and actin are known to play a role in the virulence of T. gondii tachyzoites [12].…”

Section: Discussionsupporting

confidence: 76%

Proteomic Analysis ofToxoplasma gondiiKI-1 Tachyzoites

et al. 2010

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Abstract:We studied on the proteomic characteristics of Toxoplasma gondii KI-1 tachyzoites which were originally isolated from a Korean patient, and compared with those of the well-known virulent RH strain using 2-dimensional electrophoresis (2-DE), mass spectrometry, and quantitative real-time PCR. Two-dimensional separation of the total proteins isolated from KI-1 tachyzoites revealed up to 150 spots, of which 121 were consistent with those of RH tachyzoites. Of the remaining 29 spots, 14 showed greater than 5-fold difference in density between the KI-1 and RH tachyzoites at a pH of 5.0-8.0. Among the 14 spots, 5 from the KI-1 isolate and 7 from the RH strain were identified using MALDI-TOF mass spectrometry and database searches. The spots from the KI-1 tachyzoites were dense granule proteins (GRA 2, 3, 6, and 7), hypoxanthine-guanine-xanthine phosphoribosyltransferase (HGRPTase), and uracil phosphoribosyltransferase (UPRTase). The spots from the RH strain were surface antigen 1 (SAG 1), L-lactate dehydrogenase (LDH), actin, chorismate synthase, peroximal catalase, hexokinase, bifunctional dihydrofolate reductase-thymidylate synthase (DHTR-TS), and nucleosidetriphosphatases (NTPases). Quantitative real-time PCR supported our mass spectrometric results by showing the elevated expression of the genes encoding GRA 2, 3, and 6 and UPRTase in the KI-1 tachyzoites and those encoding GRA 7, SAG 1, NTPase, and chorismate synthase in the RH tachyzoites. These observations demonstrate that the protein compositions of KI-1 and RH tachyzoites are similar but differential protein expression is involved in virulence.

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Section: Discussionsupporting

confidence: 76%

Proteomic Analysis ofToxoplasma gondiiKI-1 Tachyzoites

et al. 2010

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“…After host cell invasion, this protein is secreted into the vacuolar network, the parasitophorous vacuole membrane (PVM), and extensions protruding into the cytoplasm. TgGRA7 accumulates within the PV and PVM in tachyzoite-infected cells and in the cytoplasm of bradyzoite-infected cells (13,15). Several reports have demon-strated the usefulness of TgGRA7 as a serodiagnostic marker of toxoplasmosis.…”

mentioning

confidence: 99%

“…Dense granule antigen proteins of T. gondii (TgGRAs) are identified as secretory proteins found abundantly within the parasitophorous vacuole (PV) surrounding the parasites (13). Members of this family are potential antigens for the development of a diagnostic tool for toxoplasmosis.…”

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confidence: 99%

Development of an Immunochromatographic Assay Based on Dense Granule Protein 7 for Serological Detection of Toxoplasma gondii Infection

Terkawi

Kameyama

Rasul

et al. 2013

Clin Vaccine Immunol

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Dense granule antigen proteins derived from Toxoplasma gondii (TgGRAs) are potential antigens for the development of diagnostic tools. TgGRA7 and TgGRA14 were detected in the peritoneal fluid of T. gondii-infected mice, suggesting that TgGRAs may be highly antigenic proteins. Here, TgGRA7 and TgGRA14 were evaluated as candidates for the development of a marker for a rapid diagnostic test. The specificity and sensitivity of purified recombinant proteins of TgGRA7 and TgGRA14 were compared in an indirect enzyme-linked immunosorbent assay (iELISA) using a series of serum samples from T. gondii-experimentally infected mice and using recombinant T. gondii major surface antigen 2 (TgSAG2) as a reference control. The iELISA with TgGRA7 showed the greatest diagnostic accuracy and could detect anti-TgGRA7 antibody in acute and chronic infections. A total of 59 field samples from pigs were also examined by the iELISAs, and the results compared with those of the latex agglutination test (LAT). Among the three recombinant antigens, TgGRA7 had the highest rates of positivity, with significant concordance (88.14) and kappa value (0.76) in comparison with the results using LAT. Furthermore, an immunochromatographic test (ICT) based on recombinant TgGRA7 was developed for rapid detection of antibodies to the infection. The ICT differentiated clearly between sera from T. gondii-infected mice and uninfected or Neospora caninum-infected mice. Pig sera were examined with the ICT, and the results compared favorably with those of LAT and iELISA for TgGRA7, with kappa values of 0.66 and 0.70 to 0.79, respectively. These data suggest that the ICT based on TgGRA7 is a promising diagnostic tool for routine testing in the clinic and mass screening of samples in the field.

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“…Among identified GRA antigens, at least 12 out of 14 GRA antigens have been detected from T. gondii tachyzoites as excretory/secretory antigens (Nam, 2009). They are believed to be involved in parasite survival and virulence (Michelin et al, 2009;Rome et al, 2008).…”

Section: Dense Granule Antigens (Gra)mentioning

confidence: 99%