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Siachoque H Guzman F Burgos J Patarroyo ME Gomez Marin JE 《Experimental parasitology》2006,114(1):62-65
Vaccines are promising for the control of toxoplasmosis. Here, we evaluated the immunogenicity of 17 peptides derived from SAG1 surface protein of Toxoplasma gondii in CH3 mice. Only 8 of 16 peptides induced specific antibodies. After a lethal challenge, only the vaccination with 4 of 17 peptides that were from the carboxy terminal end of the protein conferred significant survival. Our work shows that vaccination with peptides from the carboxy-terminal positions of SAG1 major surface protein of Toxoplasma protects mice against a lethal challenge. 相似文献
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Persat F Diana J Benadiba C Ferrandiz J Péguet-Navarro J Peyron F Picot S Schmitt D Vincent C 《Experimental parasitology》2007,115(1):103-106
Human dendritic cells (DC) obtained in vitro from CD34(+) progenitors (CD34-DC) or blood monocytes (mo-DC) are different DC which may be used in a model of T. gondii infection. We compared the survival, infection rate and cell surface receptor expression of both DC types after living T. gondii tachyzoite infection. CD34-DC appeared less resistant to the parasite than mo-DC. At 48h post-infection, chemokine receptors responsible for DC homing and migration were absent in mo-DC, while down regulation of CCR6 and up regulation of CCR7 was observed in CD34-DC. This result, suggesting migration ability of CD34-DC, was confirmed by in vitro migration experiments against different chemokines. Tachyzoite supernatant, used as chemokine, attracted immature CD34-DC as observed by MIP3alpha, while MIP3beta, as expected, attracted mature CD34-DC. Under similar conditions, no significant difference was noticed between mature or immature mo-DC. These data indicated that CD34-DC represent an alternative model that allows migration assay of infected DC by T. gondii. 相似文献
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He H Tan M Pamarthy D Wang G Ahmed K Sun Y 《Molecular and cellular biochemistry》2007,295(1-2):179-188
Sensitive to Apoptosis Gene (SAG), a RING component of SCF E3 ubiquitin ligase, was shown to be phosphorylated by protein
kinase CK2 at the Thr10 residue. It is, however, unknown whether this phosphorylation is stress-responsive or whether the
phosphorylation changes its E3 ubiquitin ligase activity. To address these, we made a specific antibody against the phosphor-SAGThr10. Transient transfection experiment showed that SAG was phosphorylated at Thr10 which can be significantly inhibited by TBB,
a relatively specific inhibitor of protein kinase CK2. To determine whether this SAG phosphorylation is stress-responsive,
we defined a chemical-hypoxia condition in which SAG and CK2 were both induced. Under this condition, we failed to detect
SAG phosphorylation at Thr10, which was readily detected, however, in the presence of MG132, a proteasome inhibitor, suggesting
that the phosphorylated SAG has undergone a rapid degradation. To further define this, we made two SAG mutants, SAG-T10A which
abolishes the SAG phosphorylation and SAG-T10E, which mimics the constitutive SAG phosphorylation. The half-life study revealed
that indeed, SAG-T10E has a much shorter protein half-life (2 h), as compared to wild-type SAG (10 h). Again, rapid degradation
of SAG-T10E in cells can be blocked by MG132. Thus, it appears that CK2-induced SAG phosphorylation at Thr10 regulates its
stability through a proteasome-dependent pathway. Immunocytochemistry study showed that SAG as well as its phosphorylation
mutants, was mainly localized in nucleus and lightly in cytoplasm. Hypoxia condition did not change their sub-cellular localization.
Finally, an in vitro ubiqutination assay showed that SAG mutation at Thr10 did not change its E3 ligase activity when complexed with cullin-1.
These studies suggested that CK2 might regulate SAG-SCF E3 ligase activity through modulating SAG’s stability, rather than
its enzymatic activity directly. 相似文献
78.
A role of carboxy-terminal region of Toxoplasma gondii-heat shock protein 70 in enhancement of T. gondii infection in mice 总被引:2,自引:0,他引:2
We investigated the role of recombinant Toxoplasma gondii heat shock protein (rT.g.HSP) 70-full length, rT.g.HSP70-NH2-terminal region, or rT.g.HSP70-carboxy-terminal region in prophylactic immunity in C57BL/6 mice perorally infected with Fukaya cysts of T. gondii. At 3, 4, 5, and 6 weeks after infection, the number of T. gondii in the brain tissue of each mouse was measured by quantitative competitive-polymerase chain reaction (QC-PCR) targeting the surface antigen (SAG) 1 gene. Immunization with rT.g.HSP70-full length or r.T.g.HSP70-carboxy-terminal region increased the number of T. gondii in the brain tissue after T. gondii infection, whereas immunization with rT.g.HSP70-NH2-terminal region did not. These results suggest that T.g.HSP70-carboxy-terminal region as well as T.g.HSP70-full length may induce deleterious effects on the protective immunity of mice infected with a cyst-forming T. gondii strain, Fukaya. 相似文献
79.
Khadijeh Khanaliha Mohammad Hossein Motazedian Bahram Kazemi Bahador Shahriari Mojgan Bandehpour Zarin Sharifniya 《The Korean journal of parasitology》2014,52(2):137-142
Serologic tests are widely accepted for diagnosing Toxoplasma gondii but purification and standardization of antigen needs to be improved. Recently, surface tachyzoite and bradyzoite antigens have become more attractive for this purpose. In this study, diagnostic usefulness of 3 recombinant antigens (SAG1, SAG2, and SAG3) were evaluated, and their efficacy was compared with the available commercial ELISA. The recombinant plasmids were transformed to JM109 strain of Escherichia coli, and the recombinants were expressed and purified. Recombinant SAG1, SAG2, and SAG3 antigens were evaluated using different groups of sera in an ELISA system, and the results were compared to those of a commercial IgG and IgM ELISA kit. The sensitivity and specificity of recombinant surface antigens for detection of anti-Toxoplasma IgG in comparison with commercially available ELISA were as follows: SAG1 (93.6% and 92.9%), SAG2 (100.0% and 89.4%), and SAG3 (95.4% and 91.2%), respectively. A high degree of agreement (96.9%) was observed between recombinant SAG2 and commercial ELISA in terms of detecting IgG anti-Toxoplasma antibodies. P22 had the best performance in detecting anti-Toxoplasma IgM in comparison with the other 2 recombinant antigens. Recombinant SAG1, SAG2, and SAG3 could all be used for diagnosis of IgG-specific antibodies against T. gondii. 相似文献
80.
Two promoters of senescence-associated ARABIDOPSIS genes, SAG12 and SAG13, were used in tomato plants to express IPT that catalyzes the rate-limiting step in cytokinin biosynthesis. Expression of these heterologous promoters in tomato plants was analyzed using the reporter gene beta-glucuronidase. Both promoters are expressed in tomato leaves in a manner similar to their expression in ARABIDOPSIS plants. The SAG12 promoter is very specific to senescing leaves, whereas the SAG13 promoter is expressed in mature leaves prior to the onset of visible senescence and its expression increases in senescing leaves. Expression of both promoters in tomato tissues other than leaves was very low . IPT expressed under the control of SAG12 and SAG13 promoters ( PSAG12::IPT and PSAG13::IPT, respectively) resulted in suppression of leaf senescence and advanced flowering, as well as in a slight increase in fruit weight and fruit total soluble solids (TSS). However, expression of PSAG13::IPT also led to stem thickening, short internodal distances and loss of apical dominance. In contrast to the autoregulation of PSAG12::IPT, PSAG13::IPT is expressed at higher levels in mature leaves. This difference is likely due to PSAG13::IPT exhibiting two phases of expression - a senescence-independent expression prior to the onset of senescence that is not subjected to autoregulation by cytokinin, and enhanced expression throughout senescence which is autoregualted by cytokinin. This moderate different autoregulated behavior of PSAG12::IPT and PSAG13::IPT markedly influenced plant development, emphasizing the biological effects of cytokinin in addition to senescence inhibition. 相似文献