Binding of a Monoclonal Antibody to Sporozoites ofSarcocystis singaporensisEnhances Escape from the Parasitophorous Vacuole, Which Is Necessary for Intracellular Development
| Autor: | Ute Mackenstedt, Damaris Kliemt, Thomas Jäkel, E. Wallstein, C. Archer-Baumann, F. Müncheberg, B. Weingarten |
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| Rok vydání: | 2001 |
| Předmět: |
Intracellular Fluid
Cytoplasm medicine.drug_class Immunology Antibodies Protozoan Gene Expression Antigens Protozoan Vacuole Monoclonal antibody Microbiology Cell Line Histones Apicomplexa medicine Animals Cellular Microbiology: Pathogen-Host Cell Molecular Interactions Host cell cytosol biology Antibodies Monoclonal Sarcocystis Acetylation biology.organism_classification Molecular biology Rats Cytosol Infectious Diseases Vacuoles biology.protein Parasitology Antibody Cell Division Intracellular |
| Zdroj: | Infection and Immunity. 69:6475-6482 |
| ISSN: | 1098-5522 0019-9567 |
| Popis: | Early intracellular development in vitro of the cyst-forming protozoonSarcocystis singaporensisand 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 ofSarcocystis. |
| Databáze: | OpenAIRE |
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