Identification and characterization of a Fc Receptor activity on the <i>Toxoplasma gondii</i> tachyzoite

Vercammen, Martine; Bouhdidi, A el; Messaoud, A. Ben; Meuter, F. De; Bazin, Hervé; Dubremetz, Jean François; Carlier, Yves

doi:10.1046/j.1365-3024.1998.t01-1-00124.x

Cited by 4 publications

(2 citation statements)

References 29 publications

(31 reference statements)

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“…In this study, the Fc fragment was derived from mouse IgG2a. A decade ago, mouse monoclonal IgG2a antibodies were shown to bind the T. gondii membrane, and it was found that the binding site was not the Fab domain but the Fc fragment [55].…”

Section: Discussionmentioning

confidence: 99%

A Novel PAN/Apple Domain-Containing Protein from Toxoplasma gondii: Characterization and Receptor Identification

et al. 2012

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Toxoplasma gondii is an intracellular parasite that invades nucleated cells, causing toxoplasmosis in humans and animals worldwide. The extremely wide range of hosts susceptible to T. gondii is thought to be the result of interactions between T. gondii ligands and receptors on its target cells. In this study, a host cell-binding protein from T. gondii was characterized, and one of its receptors was identified. P104 (GenBank Access. No. CAJ20677) is 991 amino acids in length, containing a putative 26 amino acid signal peptide and 10 PAN/apple domains, and shows low homology to other identified PAN/apple domain-containing molecules. A 104-kDa host cell-binding protein was detected in the T. gondii lysate. Immunofluorescence assays detected P104 at the apical end of extracellular T. gondii. An Fc-fusion protein of the P104 N-terminus, which contains two PAN/apple domains, showed strong affinity for the mammalian and insect cells evaluated. This binding was not related to protein-protein or protein-lipid interactions, but to a protein-glycosaminoglycan (GAG) interaction. Chondroitin sulfate (CS), a kind of GAG, was shown to be involved in adhesion of the Fc-P104 N-terminus fusion protein to host cells. These results suggest that P104, expressed at the apical end of the extracellular parasite, may function as a ligand in the attachment of T. gondii to CS or other receptors on the host cell, facilitating invasion by the parasite.

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Section: Discussionmentioning

confidence: 99%

A Novel PAN/Apple Domain-Containing Protein from Toxoplasma gondii: Characterization and Receptor Identification

et al. 2012

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“…Therefore, it was the aim of the second part of this work to investigate this phenomenon in more detail and to characterize the molecule recognized by the antibody. Although it is known that parasites capture antibodies through immunoglobulin binding proteins (Fc receptors) which can increase their infective capacity (33,37), interaction of a parasite-specific antibody with its antigen on the protozoan's surface has not been observed to raise infectivity.…”

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Binding of a Monoclonal Antibody to Sporozoites ofSarcocystis singaporensisEnhances Escape from the Parasitophorous Vacuole, Which Is Necessary for Intracellular Development

et al. 2001

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Early intracellular development in vitro of the cyst-forming protozoon Sarcocystis singaporensis and the influence of a monoclonal antibody on invasion, intracellular localization, and development of sporozoites were studied. As revealed by immunofluorescence using parasite-specific antibodies which labeled the parasitophorous vacuole membrane (PVM) and by ultrastructural analysis, sporozoites invaded pneumonocytes of the rat via formation of a parasitophorous vacuole (PV). About half of the sporozoites left this compartment within the first 8 h postinfection to enter the host cell cytosol. By semiquantitative analysis of acetyl-histone H4 expression of sporozoites, a marker linked to early gene expression of eukaryotic cells, we show (supported by ultrastructural analysis) that escape from the PV appears to be necessary for early intracellular development. More than 90% of sporozoites located in the cytosol expressed high levels of acetylated histone H4 in the nucleus, whereas only a quarter of the intravacuolar sporozoites exhibited a similar signal. As revealed by ultrastructural analysis, young schizonts all resided in the cytosol. Specific binding of a monoclonal antibody (11D5/H3) to sporozoites before invasion significantly enhanced their escape from the PV, whereas cell invasion itself remained unaffected. The antibody actually increased proliferation of the parasites in vitro, providing a further link between residence in the cytosol and successful intracellular development. Monoclonal antibody 11D5/H3 precipitated a major 58-kDa antigen from oocyst-sporocyst extracts and reacted with the cytoplasm and the surface of sporozoites in immunofluorescence assays. Collectively, the observed antibody-parasite interaction suggests the existence of a signaling event that influences intracellular development of Sarcocystis.Cyst-forming coccidia of the genus Sarcocystis are among the most prevalent parasites of livestock and are responsible for considerable economic losses (10, 15). Furthermore, recent outbreaks of Sarcocystis-induced disease among humans in tropical countries (3) underscore the increasing importance of these parasites for public health (31).A peculiar aspect of Sarcocystis infection has been known for a long time but has received little attention: the possible escape of sporozoites from the parasitophorous vacuole (PV) after invasion of host cells. Early observations in vivo and ultrastructural studies of infected cell cultures of bovine pulmonary artery endothelial cells and bovine monocytes revealed that Sarcocystis cruzi sporozoites as well as the resulting schizonts were located free in the host cell cytoplasm, i.e., not surrounded by a PV (11, 34). We have extended this observation to Sarcocystis singaporensis, a species that infects rats as intermediate hosts and specifically develops inside endothelial cells and pneumonocytes, a characteristic that renders it a suitable model for Sarcocystis infections in the laboratory (21). To date, however, nothing is known about a possible escape from ...

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Identification of circulating antigens, including an immunoglobulin binding protein, from Toxoplasma gondii tissue cyst and tachyzoites in murine toxoplasmosis

Villavedra

Rampoldi

Carol

et al. 2001

International Journal for Parasitology

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Identification and characterization of a Fc Receptor activity on the Toxoplasma gondii tachyzoite

Cited by 4 publications

References 29 publications

A Novel PAN/Apple Domain-Containing Protein from Toxoplasma gondii: Characterization and Receptor Identification

A Novel PAN/Apple Domain-Containing Protein from Toxoplasma gondii: Characterization and Receptor Identification

Binding of a Monoclonal Antibody to Sporozoites ofSarcocystis singaporensisEnhances Escape from the Parasitophorous Vacuole, Which Is Necessary for Intracellular Development

Identification of circulating antigens, including an immunoglobulin binding protein, from Toxoplasma gondii tissue cyst and tachyzoites in murine toxoplasmosis

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