Molecular cloning and characterization of a novel acidic microneme protein (Etmic-2) from the apicomplexan protozoan parasite, Eimeria tenella

Tomley, Fiona M.; Bumstead, Janene M.; Billington, Karen; Dunn, P. P. J.

doi:10.1016/0166-6851(96)02662-x

Cited by 115 publications

(63 citation statements)

References 25 publications

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“…2C; references 20 and 30). This is a typical staining pattern of MIC2 of Toxoplasma gondii and other apicomplexan micronemal proteins that are released onto the parasite surface upon target cell contact (9,15,39). Bright surface caps were distinct from the bipolar, nucleus-sparing staining of TRAP obtained when sporozoites are permeabilized ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Antibodies against Thrombospondin-Related Anonymous Protein Do Not InhibitPlasmodiumSporozoite Infectivity In Vivo

Gantt¹,

Persson²,

Rose

et al. 2000

Infect Immun

101

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Thrombospondin-related anonymous protein (TRAP), a candidate malaria vaccine antigen, is required for Plasmodium sporozoite gliding motility and cell invasion. For the first time, the ability of antibodies against TRAP to inhibit sporozoite infectivity in vivo is evaluated in detail. TRAP contains an A-domain, a wellcharacterized adhesive motif found in integrins. We modeled here a three-dimensional structure of the TRAP A-domain of Plasmodium yoelii and located regions surrounding the MIDAS (metal ion-dependent adhesion site), the presumed business end of the domain. Mice were immunized with constructs containing these Adomain regions but were not protected from sporozoite challenge. Furthermore, monoclonal and rabbit polyclonal antibodies against the A-domain, the conserved N terminus, and the repeat region of TRAP had no effect on the gliding motility or sporozoite infectivity to mice. TRAP is located in micronemes, secretory organelles of apicomplexan parasites. Accordingly, the antibodies tested here stained cytoplasmic TRAP brightly by immunofluorescence. However, very little TRAP could be detected on the surface of sporozoites. In contrast, a dramatic relocalization of TRAP onto the parasite surface occurred when sporozoites were treated with calcium ionophore. This likely mimics the release of TRAP from micronemes when a sporozoite contacts its target cell in vivo. Contact with hepatoma cells in culture also appeared to induce the release of TRAP onto the surface of sporozoites. If large amounts of TRAP are released in close proximity to its cellular receptor(s), effective competitive inhibition by antibodies may be difficult to achieve.

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Section: Resultsmentioning

confidence: 99%

Antibodies against Thrombospondin-Related Anonymous Protein Do Not InhibitPlasmodiumSporozoite Infectivity In Vivo

Gantt¹,

Persson²,

Rose

et al. 2000

Infect Immun

101

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“…Attachment and invasion mechanisms mediated by the interaction of specific parasite and host molecules have been described for apicomplexan protozoa closely related to C. parvum, including Toxoplasma gondii (5,11,12,29,35,36,60,64), Neospora caninum (41,51,83), Eimeria tenella (2,7,87,88), and Plasmodium spp. (14,15,20,30,57,82).…”

Section: Discussionmentioning

confidence: 99%

“…The refractory nature of persistent C. parvum infection to existing therapies may relate to the parasite's autoinfective life cycle stages, superficial compartmentalization within the host cell, and novel metabolic pathways (19,27,90). Of additional fundamental significance, limited knowledge on the pathogenesis of attachment of the infective zoite stages to host cells and subsequent invasion has hampered development of targeted intervention strategies for cryptosporidiosis.Because apical complex and surface molecules of C. parvum (3, 16-18, 39, 43-45, 47, 52, 62, 66, 67, 73-75, 77, 79, 80, 85) and other closely related apicomplexan parasites (7,8,11,14,15,29,35,36,41,51,60,64,83,87,88) are involved in attachment, invasion, and intracellular development (2,5,8,20,23,61,63,68,84), such molecules may provide rational targets for immunological or pharmacological therapy. Additionally, the host cell receptors to which such parasite molecules bind may provide novel avenues for receptor-based control strategies (12,14,15,30,57,62,64,82).…”

mentioning

confidence: 99%

Characterization of an Intestinal Epithelial Cell Receptor Recognized by theCryptosporidium parvumSporozoite Ligand CSL

2001

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The protozoan parasite Cryptosporidium parvum is a leading cause of diarrhea in humans and neonatal calves. The absence of approved parasite-specific drugs, vaccines, and immunotherapies for cryptosporidiosis relates in part to limited knowledge on the pathogenesis of zoite attachment and invasion. We recently reported that the C. parvum apical complex glycoprotein CSL contains a zoite ligand for intestinal epithelial cells which is defined by monoclonal antibody (MAb) 3E2. In the present study, the host cell receptor for CSL was characterized. For these studies, a panel of epithelial and mesenchymal cell lines was examined for permissiveness to C. parvum and the ability to bind CSL. Cells of epithelial origin were significantly more permissive and bound significantly greater quantities of CSL than cells of mesenchymal origin. Caco-2 intestinal cells were selected from the epithelial panel for further characterization of the CSL receptor. Immunoelectron microscopy demonstrated that CSL bound initially to the surface of Caco-2 cells and was rapidly internalized. The molecule bound by CSL was identified as an 85-kDa Caco-2 cell surface protein by radioimmunoprecipitation and CSL affinity chromatography. Sporozoite incubation with the isolated 85-kDa protein reduced binding of MAb 3E2. Further, attachment and invasion were significantly inhibited when sporozoites were incubated with the 85-kDa protein prior to inoculation onto Caco-2 cells. These observations indicate that the 85-kDa protein functions as a Caco-2 cell receptor for CSL. CSL also bound specifically to intestinal epithelium from calves, indicating receptor expression in a second important host species. Molecular characterization of the CSL receptor may lead to novel avenues for disrupting ligand-receptor interactions in the pathogenesis of C. parvum infection.The apicomplexan parasite Cryptosporidium parvum is an important cause of diarrhea in humans and in calves and other economically important food animals worldwide (27). Although significant advances have occurred (3, 16, 17, 21, 25, 33, 43, 47, 62, 65-68, 79, 80, 84, 86), prevention and treatment of the disease remain problematic due to the absence of approved vaccines or immunotherapies and the lack of consistently effective parasite-specific pharmaceuticals (reviewed in references 4, 13, 21, 72, 90, and 95). The refractory nature of persistent C. parvum infection to existing therapies may relate to the parasite's autoinfective life cycle stages, superficial compartmentalization within the host cell, and novel metabolic pathways (19,27,90). Of additional fundamental significance, limited knowledge on the pathogenesis of attachment of the infective zoite stages to host cells and subsequent invasion has hampered development of targeted intervention strategies for cryptosporidiosis.Because apical complex and surface molecules of C. parvum (3, 16-18, 39, 43-45, 47, 52, 62, 66, 67, 73-75, 77, 79, 80, 85) and other closely related apicomplexan parasites (7,8,11,14,15,29,35,36,41,51,60,64,83,87,88) ...

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“…Over the past 10 years, Eimeria genes encoding protective antigens have been cloned, and their gene products have been characterized. These include parasite surface proteins (15), as well as internal proteins associated with subcellular organelles, such as the rhoptries (40), microneme (41), and refractile bodies (42). Although many of the reported Eimeria recombinant proteins elicit some aspects of host immunity in vaccinated recipients (16,43), the natures of these protective antigens need to be better characterized, particularly with respect to their roles in parasite growth and development and the infectious process (45,46).…”

mentioning

confidence: 99%

Protective Immunity against Eimeria acervulina following In Ovo Immunization with a Recombinant Subunit Vaccine and Cytokine Genes

Ding

Lillehoj

Quiróz³

et al. 2004

Infect Immun

104

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A purified recombinant protein from Eimeria acervulina (3-1E) was used to vaccinate chickens in ovo against coccidiosis both alone and in combination with expression plasmids encoding the interleukin 1 (IL-1), IL-2, IL-6, IL-8, IL-15, IL-16, IL-17, IL-18, or gamma interferon (IFN-␥) gene. When used alone, vaccination with 100 or 500 g of 3-1E resulted in significantly decreased oocyst shedding compared with that in nonvaccinated chickens. Simultaneous vaccination of the 3-1E protein with the IL-1, -15, -16, or -17 gene induced higher serum antibody responses than 3-1E alone. To evaluate protective intestinal immunity, vaccinated birds were challenged with live E. acervulina oocysts 14 days posthatch, and fecal-oocyst shedding and body weight gain were determined as parameters of coccidiosis. Chickens vaccinated with 3-1E protein showed significantly lower oocyst shedding and normal body weight gain than nonvaccinated and infected controls. Simultaneous immunization with 3-1E and the IL-2, -15, -17, or -18 or IFN-␥ gene further reduced oocyst shedding compared with that achieved with 3-1E alone. These results provide the first evidence that in ovo vaccination with the recombinant 3-1E Eimeria protein induces protective intestinal immunity against coccidiosis, and this effect was enhanced by coadministration of genes encoding immunity-related cytokines.

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Molecular cloning and characterization of a novel acidic microneme protein (Etmic-2) from the apicomplexan protozoan parasite, Eimeria tenella

Cited by 115 publications

References 25 publications

Antibodies against Thrombospondin-Related Anonymous Protein Do Not InhibitPlasmodiumSporozoite Infectivity In Vivo

Antibodies against Thrombospondin-Related Anonymous Protein Do Not InhibitPlasmodiumSporozoite Infectivity In Vivo

Characterization of an Intestinal Epithelial Cell Receptor Recognized by theCryptosporidium parvumSporozoite Ligand CSL

Protective Immunity against Eimeria acervulina following In Ovo Immunization with a Recombinant Subunit Vaccine and Cytokine Genes

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