Trypanosoma cruzi Calreticulin Topographical Variations in Parasites Infecting Murine Macrophages |
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| Authors: | Andrea González Carolina Valck Gittith Sánchez Steffen H?rtel Jorge Mansilla Galia Ramírez María Soledad Fernández José Luis Arias Norbel Galanti Arturo Ferreira |
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| Institution: | Programa Disciplinario de Inmunología, Programa de Genética Humana, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas; Laboratorio de Análisis de Imágenes Científicas (SCIAN), Instituto de Neurociencias Biomédicas, Facultad de Medicina; Departamento de Medicina Preventiva Animal, Departamento de Ciencias Biológicas Animales, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Chile |
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| Abstract: | Trypanosoma cruzi calreticulin (TcCRT), a 47-kDa chaperone, translocates from the endoplasmic reticulum to the area of flagellum emergence. There, it binds to complement components C1 and mannan-binding lectin (MBL), thus acting as a main virulence factor, and inhibits the classical and lectin pathways. The localization and functions of TcCRT, once the parasite is inside the host cell, are unknown. In parasites infecting murine macrophages, polyclonal anti-TcCRT antibodies detected TcCRT mainly in the parasite nucleus and kinetoplast. However, with a monoclonal antibody (E2G7), the resolution and specificity of the label markedly improved, and TcCRT was detected mainly in the parasite kinetoplast. Gold particles, bound to the respective antibodies, were used as probes in electron microscopy. This organelle may represent a stopover and accumulation site for TcCRT, previous its translocation to the area of flagellum emergence. Finally, early during T. cruzi infection and by unknown mechanisms, an important decrease in the number of MHC-I positive host cells was observed. |
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