13 results on '"Guionaud C"'
Search Results
2. Chromosomal assignment of five equine HTR genes by FISH and RH mapping
- Author
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Prause, A., Guionaud, C. T., Klukowska-Rötzler, J., Giulotto, E., Magnani, E., Chowdhary, B. P., Philipp, U., Leeb, T., and Mevissen, M.
- Published
- 2007
3. Intraperitoneal and intra-nasal vaccination of mice with three distinct recombinant Neospora caninum antigens results in differential effects with regard to protection against experimental challenge with Neospora caninum tachyzoites
- Author
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DEBACHE, K., GUIONAUD, C., ALAEDDINE, F., HEMPHILL, A., DEBACHE, K., GUIONAUD, C., ALAEDDINE, F., and HEMPHILL, A.
- Abstract
Recombinant NcPDI(recNcPDI), NcROP2(recNcROP2), and NcMAG1(recNcMAG1) were expressed in Escherichia coli and purified, and evaluated as potential vaccine candidates by employing the C57Bl/6 mouse cerebral infection model. Intraperitoneal application of these proteins suspended in saponin adjuvants lead to protection against disease in 50% and 70% of mice vaccinated with recNcMAG1 and recNcROP2, respectively, while only 20% of mice vaccinated with recNcPDI remained without clinical signs. In contrast, a 90% protection rate was achieved following intra-nasal vaccination with recNcPDI emulsified in cholera toxin. Only 1 mouse vaccinated intra-nasally with recNcMAG1 survived the challenge infection, and protection achieved with intra-nasally applied recNcROP2 was at 60%. Determination of cerebral parasite burdens by real-time PCR showed that these were significantly reduced only in recNcROP2-vaccinated animals (following intraperitoneal and intra-nasal application) and in recNcPDI-vaccinated mice (intra-nasal application only). Quantification of viable tachyzoites in brain tissue of intra-nasally vaccinated mice showed that immunization with recNcPDI resulted in significantly decreased numbers of live parasites. These data show that, besides the nature of the antigen, the protective effect of vaccination also depends largely on the route of antigen delivery. In the case of recNcPDI, the intra-nasal route provides a platform to generate a highly protective immune response
- Published
- 2017
4. Intraperitoneal and intra-nasal vaccination of mice with three distinct recombinantNeospora caninumantigens results in differential effects with regard to protection against experimental challenge withNeospora caninumtachyzoites
- Author
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DEBACHE, K., primary, GUIONAUD, C., additional, ALAEDDINE, F., additional, and HEMPHILL, A., additional
- Published
- 2009
- Full Text
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5. North American and French Caprine Arthritis-Encephalitis Viruses Emerge from Ovine Maedi-Visna Viruses
- Author
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Valas, S., primary, Benoit, C., additional, Guionaud, C., additional, Perrin, G., additional, and Mamoun, R.Z., additional
- Published
- 1997
- Full Text
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6. Intraperitoneal and intra-nasal vaccination of mice with three distinct recombinant Neospora caninum antigens results in differential effects with regard to protection against experimental challenge with Neospora caninum tachyzoites
- Author
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DEBACHE, K., GUIONAUD, C., ALAEDDINE, F., HEMPHILL, A., DEBACHE, K., GUIONAUD, C., ALAEDDINE, F., and HEMPHILL, A.
- Abstract
Recombinant NcPDI(recNcPDI), NcROP2(recNcROP2), and NcMAG1(recNcMAG1) were expressed in Escherichia coli and purified, and evaluated as potential vaccine candidates by employing the C57Bl/6 mouse cerebral infection model. Intraperitoneal application of these proteins suspended in saponin adjuvants lead to protection against disease in 50% and 70% of mice vaccinated with recNcMAG1 and recNcROP2, respectively, while only 20% of mice vaccinated with recNcPDI remained without clinical signs. In contrast, a 90% protection rate was achieved following intra-nasal vaccination with recNcPDI emulsified in cholera toxin. Only 1 mouse vaccinated intra-nasally with recNcMAG1 survived the challenge infection, and protection achieved with intra-nasally applied recNcROP2 was at 60%. Determination of cerebral parasite burdens by real-time PCR showed that these were significantly reduced only in recNcROP2-vaccinated animals (following intraperitoneal and intra-nasal application) and in recNcPDI-vaccinated mice (intra-nasal application only). Quantification of viable tachyzoites in brain tissue of intra-nasally vaccinated mice showed that immunization with recNcPDI resulted in significantly decreased numbers of live parasites. These data show that, besides the nature of the antigen, the protective effect of vaccination also depends largely on the route of antigen delivery. In the case of recNcPDI, the intra-nasal route provides a platform to generate a highly protective immune response
7. Molecular cloning and characterization of NcROP2Fam-1, a member of the ROP2 family of rhoptry proteins in Neospora caninum that is targeted by antibodies neutralizing host cell invasion in vitro.
- Author
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Alaeddine F, Hemphill A, Debache K, and Guionaud C
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Chlorocebus aethiops, Cloning, Molecular, DNA, Complementary genetics, DNA, Protozoan chemistry, DNA, Protozoan genetics, Fibroblasts parasitology, Humans, Membrane Proteins chemistry, Membrane Proteins genetics, Membrane Proteins immunology, Molecular Sequence Data, Neospora cytology, Neospora genetics, Neospora metabolism, Protein Structure, Tertiary, Protein Transport, Protozoan Proteins chemistry, Protozoan Proteins genetics, Protozoan Proteins immunology, RNA, Protozoan genetics, Sequence Analysis, DNA, Vacuoles metabolism, Vacuoles parasitology, Vero Cells, Antibodies, Protozoan immunology, Antigens, Protozoan immunology, Membrane Proteins metabolism, Neospora immunology, Protozoan Proteins metabolism
- Abstract
Recent publications demonstrated that a fragment of a Neospora caninum ROP2 family member antigen represents a promising vaccine candidate. We here report on the cloning of the cDNA encoding this protein, N. caninum ROP2 family member 1 (NcROP2Fam-1), its molecular characterization and localization. The protein possesses the hallmarks of ROP2 family members and is apparently devoid of catalytic activity. NcROP2Fam-1 is synthesized as a pre-pro-protein that is matured to 2 proteins of 49 and 55 kDa that localize to rhoptry bulbs. Upon invasion the protein is associated with the nascent parasitophorous vacuole membrane (PVM), evacuoles surrounding the host cell nucleus and, in some instances, the surface of intracellular parasites. Staining was also observed within the cyst wall of 'cysts' produced in vitro. Interestingly, NcROP2Fam-1 was also detected on the surface of extracellular parasites entering the host cells and antibodies directed against NcROP2Fam-1-specific peptides partially neutralized invasion in vitro. We conclude that, in spite of the general belief that ROP2 family proteins are intracellular antigens, NcROP2Fam-1 can also be considered as an extracellular antigen, a property that should be taken into account in further experiments employing ROP2 family proteins as vaccines.
- Published
- 2013
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8. Proteins mediating the Neospora caninum-host cell interaction as targets for vaccination.
- Author
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Hemphill A, Debache K, Monney T, Schorer M, Guionaud C, Alaeddine F, Mueller N, and Mueller J
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- Animals, Cattle, Cell Adhesion immunology, Coccidiosis immunology, Host-Parasite Interactions, Microscopy, Electron, Scanning veterinary, Microscopy, Electron, Transmission veterinary, Neospora ultrastructure, Antigens, Protozoan metabolism, Antigens, Surface metabolism, Cattle Diseases immunology, Cattle Diseases parasitology, Coccidiosis veterinary, Neospora immunology, Protozoan Proteins metabolism, Protozoan Vaccines therapeutic use
- Abstract
Neospora caninum is an apicomplexan parasite that is capable of infecting, a wide range of tissues. The fact that Neospora represents an important abortion-causing parasite in cattle has transformed neosporosis research from an earlier, rather esoteric field, to a significant research topic, and considerable investments have been made in the last years to develop an efficacious vaccine or other means of intervention that would prevent infection and abortion due to N. caninum infection in cattle. Antigenic molecules associated with proteins involved in adhesion/invasion or other parasite-host-cell interaction processes can confer protection against Neospora caninum infection, and such proteins represent valuable targets for the development of a vaccine to limit economical losses due to neosporosis. Although not ideal, small laboratory animal models that mimic cerebral infection, acute disease and fetal loss upon infection during pregnancy have been used for the assessment of vaccine candidates, in parallel with studies on experimental infections in cattle. Herein, we review and critically assess these vaccination approaches and discuss potential options for improvements.
- Published
- 2013
- Full Text
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9. Experimental treatment of Neospora caninum-infected mice with the arylimidamide DB750 and the thiazolide nitazoxanide.
- Author
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Debache K, Guionaud C, Kropf C, Boykin D, Stephens CE, and Hemphill A
- Subjects
- Administration, Oral, Amidines adverse effects, Amidines pharmacology, Animals, Body Weight drug effects, Brain parasitology, Cell Line, Chlorocebus aethiops, Coccidiostats adverse effects, Coccidiostats pharmacology, DNA, Protozoan analysis, Disease Models, Animal, Female, Fibroblasts parasitology, Humans, Injections, Intraperitoneal, Mice, Mice, Inbred BALB C, Nitro Compounds, Polymerase Chain Reaction, Pyridines adverse effects, Pyridines pharmacology, Random Allocation, Thiazoles adverse effects, Thiazoles pharmacology, Vero Cells, Amidines therapeutic use, Coccidiosis drug therapy, Coccidiostats therapeutic use, Neospora drug effects, Pyridines therapeutic use, Thiazoles therapeutic use
- Abstract
The cationic arylimidamide DB750 and the thiazolide nitazoxanide had been shown earlier to be effective against Neospora caninum tachyzoites in vitro with an IC(50) of 160nM and 4.23μM, respectively. In this study, we have investigated the effects of DB750 and nitazoxanide treatments of experimentally infected Balb/c mice, by applying the drugs either through the oral or the intraperitoneal route. In experiment 1, administration of DB750 (2mg/kg/day) and nitazoxanide (150mg/kg/day) started already 3 days prior to experimental infection of mice with 2×10(6) tachyzoites. Following infection, the drugs were further administrated daily for a period of 2 weeks, either orally or intraperitoneally. Intraperitoneal injection of DB750 was well tolerated by the mice, but treatment with nitazoxanide resulted in death of all mice within 3 days. Upon intraperitoneal application of DB750, the cerebral parasite load was significantly reduced compared to all other groups, while oral application of DB750 and nitazoxanide were not as effective, and resulted in significant weight loss. In experiment 2, mice were infected with 2×10(6) tachyzoites and at 2 weeks post-infection, DB750 (2mg/kg/day) was applied by intraperitoneal injections for 14 days. In the DB750-treated group, only 2 out of 12 mice succumbed to infection, compared to 7 out of 12 mice in the placebo-group. DB750 treatment also resulted in significantly reduced cerebral parasite burden, and reduced numbers of viable tachyzoites. Our data suggest that DB750 exerted its activity also after crossing the blood-brain barrier, and that this class of compounds could be promising for the control of N. caninum-associated disease., (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Published
- 2011
- Full Text
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10. Molecular characterization of Neospora caninum MAG1, a dense granule protein secreted into the parasitophorous vacuole, and associated with the cyst wall and the cyst matrix.
- Author
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Guionaud C, Hemphill A, Mevissen M, and Alaeddine F
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Chlorocebus aethiops, Immunization, Life Cycle Stages, Mice, Molecular Sequence Data, Neospora genetics, Neospora metabolism, Protozoan Proteins chemistry, Protozoan Proteins genetics, Protozoan Proteins immunology, Protozoan Proteins metabolism, Rabbits, Recombinant Proteins chemistry, Recombinant Proteins genetics, Recombinant Proteins immunology, Recombinant Proteins metabolism, Sequence Analysis, DNA, Vero Cells, Antigens, Protozoan chemistry, Antigens, Protozoan genetics, Antigens, Protozoan immunology, Antigens, Protozoan metabolism, Keratinocytes parasitology, Neospora growth & development, Neospora pathogenicity, Vacuoles metabolism
- Abstract
Summary: In Neospora caninum and Toxoplasma gondii, the parasitophorous vacuole (PV) is synthesized at the time of infection. During tachyzoite-to-bradyzoite stage conversion, the PV is later transformed into a tissue cyst that allows parasites to survive in their host for extended periods of time. We report on the characterization of NcMAG1, the N. caninum orthologue of T. gondii MAG1 (matrix antigen 1; TgMAG1). The 456 amino acid predicted NcMAG1 protein is 54% identical to TgMAG1. By immunoblotting, a rabbit antiserum raised against recombinant NcMAG1 detected a major product of approximately 67 kDa in extracts of N. caninum tachyzoite-infected Vero cells, which was stained more prominently in extracts of infected Vero cells treated to induce in vitro bradyzoite conversion. Immunofluorescence and TEM localized the protein mainly within the cyst wall and the cyst matrix. In both tachyzoites and bradyzoites, NcMAG1 was associated with the parasite dense granules. Comparison between NcMAG1 and TgMAG1 amino acid sequences revealed that the C-terminal conserved regions exhibit 66% identity, while the N-terminal variable regions exhibit only 32% identity. Antibodies against NcMAG1-conserved region cross-reacted with the orthologuous protein in T. gondii but those against the variable region did not. This indicates that the variable region possesses unique antigenic characteristics.
- Published
- 2010
- Full Text
- View/download PDF
11. Vaccination with recombinant NcROP2 combined with recombinant NcMIC1 and NcMIC3 reduces cerebral infection and vertical transmission in mice experimentally infected with Neospora caninum tachyzoites.
- Author
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Debache K, Alaeddine F, Guionaud C, Monney T, Müller J, Strohbusch M, Leib SL, Grandgirard D, and Hemphill A
- Subjects
- Animals, Brain immunology, Chi-Square Distribution, Chlorocebus aethiops, DNA, Complementary, Female, Fetal Death parasitology, Infectious Disease Transmission, Vertical, Mice, Mice, Inbred BALB C, Neospora genetics, Polymerase Chain Reaction, Pregnancy, Protozoan Proteins immunology, Protozoan Vaccines genetics, Recombinant Proteins immunology, Vaccines, Synthetic immunology, Vero Cells, Brain parasitology, Brain Diseases immunology, Neospora immunology, Protozoan Vaccines immunology
- Abstract
We investigated the protective potential of recombinant his-tagged antigens recNcMIC1, recNcMIC3 and recNcROP2, applied either as single vaccines or as vaccine combinations, in BALB/c mouse models for cerebral and fetal infection. Subsequently, mice were mated and challenged by i.p. inoculation of 2 x 10(6)Neospora caninum tachyzoites at day 7 of pregnancy. The mortality and morbidity of adult mice (non-pregnant and dams) and of the newborn pups was studied for a period of 40 days following birth. Vaccination of non-pregnant mice with recNcROP2 or combinations of recNcROP2 with recNcMIC antigens significantly reduced the numbers of mice suffering from clinical signs, and morbidity was completely prevented with the combination of all three antigens. Of the dams, the groups receiving either recNcROP2 alone or the combination of all three antigens did not exhibit any morbidity, the groups receiving ROP2 mixed with either MIC1 or MIC3 exhibited reduced numbers of deaths, and in the infection control group and the adjuvant group 50% and 43% of mice, respectively, succumbed to disease. For pups, the highest survival rates were noted for the groups receiving recNcROP2 (50%) and recNcROP2/NcMIC1/NcMIC3 (35%), while in the infection- and adjuvant- control groups all pups died, the latest at days 25 and 30, respectively. Quantification of parasite DNA by N. caninum-specific real-time PCR revealed consistently lower parasite burdens in brain tissue of pups from vaccinated groups compared with the controls. However, dense granule antigen 2 (GRA2) real-time reverse transcriptase-PCR on brain tissue of surviving pups (applied here to detect viable parasites) demonstrated that only the pups from the group vaccinated with all three antigens in combination appeared free of viable tachyzoites, while in all other groups viable parasites were still present. Serological analysis of humoral (total IgG, IgG1 and IgG2a) and serum cytokine (IL-4 and IFN-gamma) responses showed that this effect was associated with a Th-2-biased immune response, with a clearly elevated IL-4/IFN-gamma ratio in the mice receiving all three antigens in combination. In conclusion, a mixture of recombinant antigens representing important secretory micronemal and rhoptry proteins leads to a significant protection against vertical transmission of N. caninum in mice.
- Published
- 2009
- Full Text
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12. Vaccination of mice with recombinant NcROP2 antigen reduces mortality and cerebral infection in mice infected with Neospora caninum tachyzoites.
- Author
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Debache K, Guionaud C, Alaeddine F, Mevissen M, and Hemphill A
- Subjects
- Animals, Antibodies, Protozoan blood, Brain Diseases immunology, Brain Diseases parasitology, Brain Diseases prevention & control, Coccidiosis metabolism, Disease Models, Animal, Enzyme-Linked Immunosorbent Assay, Immunoglobulin G blood, Mice, Mice, Inbred C57BL, Neospora metabolism, Reverse Transcriptase Polymerase Chain Reaction, Vaccination methods, Antigens, Protozoan immunology, Brain parasitology, Coccidiosis immunology, Neospora immunology, Protozoan Vaccines immunology
- Abstract
Rhoptry antigens are involved in a variety of cellular functions related to host cell invasion, formation of the parasitophorous vacuole and parasite-host cell interplay. The cDNA sequence of one of these antigens, NcROP2 was identified from Neospora caninum expressed sequence tags (ESTs), amplified by reverse transcription-PCR, expressed in Escherichia coli as a (His)(6)-tagged recombinant protein (recNcROP2) and purified over Ni(2+)-affinity chromatography. Both recNcROP2 and antibodies directed against recNcROP2 had a negative impact on N. caninum tachyzoite host cell invasion in vitro, indicating that this protein participates in the host cell entry process. Subsequently, the protective efficacy of NcROP2 as a potential vaccine candidate was evaluated in a C57BL/6 mouse cerebral disease model. Mice were vaccinated three times at 2-week intervals with recNcROP2 emulsified either in Freund's incomplete adjuvants (FIA) or saponin, and control groups were treated with adjuvants alone (adjuvants control) or PBS (infection control). Subsequently, mice were challenged with 2x10(6)N. caninum tachyzoites. Nine mice, all belonging to the infection control or adjuvants control groups, exhibited clinical signs of cerebral neosporosis and succumbed to infection, whilst no clinical signs were noted for recNcROP2-vaccinated mice. For all other animals, the experiment was terminated 35 days p.i. Cerebral parasite burdens were assessed by quantitative PCR in all mice, and were revealed to be significantly reduced in the recNcROP2-vaccinated mice. ELISA of sera revealed IgG1 to be elevated in recNcROP2-saponin vaccinated mice, whilst IgG2a was higher in recNcROP2-FIA vaccinated animals. This shows that, depending on the adjuvants used, vaccination with NcROP2 induces a protective Th-1- or Th-2-biased immune response against experimental N. caninum infection.
- Published
- 2008
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13. Neospora caninum protein disulfide isomerase is involved in tachyzoite-host cell interaction.
- Author
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Naguleswaran A, Alaeddine F, Guionaud C, Vonlaufen N, Sonda S, Jenoe P, Mevissen M, and Hemphill A
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- Animals, Base Sequence, Cell Adhesion drug effects, Cell Adhesion immunology, Cell Adhesion physiology, Chromatography, Affinity methods, DNA, Complementary genetics, DNA, Protozoan genetics, Electrophoresis, Polyacrylamide Gel methods, Microscopy, Immunoelectron, Molecular Sequence Data, Neospora genetics, Neospora physiology, Neospora ultrastructure, Protein Disulfide-Isomerases genetics, Protein Disulfide-Isomerases isolation & purification, Protozoan Proteins genetics, Protozoan Proteins physiology, Tissue Culture Techniques, Host-Parasite Interactions physiology, Neospora enzymology, Protein Disulfide-Isomerases physiology
- Abstract
We have previously shown that treatment of Neospora caninum tachyzoites with the aspartyl protease inhibitor pepstatin A reduces host cell invasion [Naguleswaran, A., Muller, N., Hemphill, A., 2003. Neospora caninum and Toxoplasma gondii: a novel adhesion/invasion assay reveals distinct differences in tachyzoite-host cell interactions. Exp. Parasitol. 104, 149-158]. Pepstatin A-affinity-chromatography led to the isolation of a major band of approximately 52 kDa which was identified as a homologue of a previously described Toxoplasma gondii putative protein disulfide isomerase (TgPDI) through tandem mass spectrometry. A BLAST search against N. caninum expressed sequence tags (ESTs) on the ApiDots server using TgPDI cDNA as query sequence revealed a 2251 bp PDI-like consensus (NcPDI), which shows 94% identity to the T. gondii homologue. In N. caninum tachyzoites, NcPDI was found mainly in the soluble hydrophilic fraction. Immunofluorescence showed that expression of NcPDI was dramatically down-regulated in the bradyzoite stage, and immunogold-EM on tachyzoites localised the protein to the cytoplasm, mostly in close vicinity to the nuclear membrane, to the micronemes, and to the parasite cell surface. However, NcPDI was absent in rhoptries and dense granules. Preincubation of tachyzoites with the sulfhydryl blocker 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), p-chloromercuribenzoic acid (pCMBA), and with the PDI inhibitor bacitracin reduced adhesion of parasites to host cells. In addition, incubation of N. caninum tachyzoites with affinity-purified anti-NcPDI antibodies reduced host cell adhesion. PDIs catalyse the formation, reduction or isomerisation of disulfide bonds. Many major components of the adhesion and invasion machinery of apicomplexan parasites are cysteine-rich and dependent on correct folding via disulfide bond formation. Thus, our data points towards an important role for surface-associated NcPDI in Neospora-host cell interaction.
- Published
- 2005
- Full Text
- View/download PDF
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