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Title: Inefficient complement system clearance of Trypanosoma cruzi metacyclic trypomastigotes enables resistant strains to invade eukaryotic cells
Authors: Cestari, Igor
Ramirez, Marcel I
Affilliation: Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Molecular de Parasitas e Vetores. Rio de Janeiro, RJ. Brasil.
Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Molecular de Parasitas e Vetores. Rio de Janeiro, RJ. Brasil.
Abstract: The complement system is the main arm of the vertebrate innate immune system against pathogen infection. For the protozoan Trypanosoma cruzi, the causative agent of Chagas disease, subverting the complement system and invading the host cells is crucial to succeed in infection. However, little attention has focused on whether the complement system can effectively control T. cruzi infection. To address this question, we decided to analyse: 1) which complement pathways are activated by T. cruzi using strains isolated from different hosts, 2) the capacity of these strains to resist the complement-mediated killing at nearly physiological conditions, and 3) whether the complement system could limit or control T. cruzi invasion of eukaryotic cells. The complement activating molecules C1q, C3, mannan-binding lectin and ficolins bound to all strains analysed; however, C3b and C4b deposition assays revealed that T. cruzi activates mainly the lectin and alternative complement pathways in non-immune human serum. Strikingly, we detected that metacyclic trypomastigotes of some T. cruzi strains were highly susceptible to complement-mediated killing in non-immune serum, while other strains were resistant. Furthermore, the rate of parasite invasion in eukaryotic cells was decreased by non-immune serum. Altogether, these results establish that the complement system recognizes T. cruzi metacyclic trypomastigotes, resulting in killing of susceptible strains. The complement system, therefore, acts as a physiological barrier which resistant strains have to evade for successful host infection.
Keywords: Trypanosoma cruzi
Eukaryotic Cells
T. cruzi strains
complement system
T. cruzi infection
Chagas disease
keywords: Trypanosoma cruzi
Células Eucarióticas
Doença de Chagas
Issue Date: 2010
Publisher: Public Library of Science
Citation: CESTARI, Igor; RAMIREZ, Marcel I. Inefficient Complement System Clearance of Trypanosoma cruzi Metacyclic Trypomastigotes Enables Resistant Strains to Invade Eukaryotic Cells. Plos One, v.5, n.3, e9721, 11p, 2010.
DOI: 10.1371/journal.pone.0009721
ISSN: 1932-6203
Copyright: open access
Appears in Collections:IOC - Artigos de Periódicos

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