RÉSUMÉ
Highly virulent strains of Trypanosoma cruzi are frequently used as murine models of Chagas' disease. However, these strains do not fully represent the spectrum of parasites involved in the human infection. In this paper, we analysed parasitaemia, mortality, tissue pathology and parasite-specific IgG serum levels in immune-deficient mice infected with Sylvio X10/4 parasites, a T. cruzi derived from a chagasic patient that yields very low parasitaemias and in C3H/HePAS mice induces a chronic cardiopathy resembling the human disease. IFN-gamma was identified as a crucial element for parasite control as its absence determined a drastic increase in parasitaemia, tissue parasitism, leukocyte infiltrates at the heart and striated muscles and mortality. The lack of IFN-gamma or IL-12p40, a molecule shared by IL-12 and IL-23, also resulted in spinal cord lesions and a progressive paralysis syndrome. Whereas IgG2a was the main Ig isotype in infected C57BL/6 mice, IL-12p40-KO mice produced IgG2a and IgG1 and IFN-gamma-KO mice produced only IgG1. The IFN-gamma-protective effect was not essentially mediated by nitric oxide (NO), inasmuch as infected iNOS-KO mice showed no parasitaemia and low tissue damage. Mice deficient in CD4(+) or CD8(+) T cells showed an intermediate phenotype with increased mortality and tissue pathology but no parasitaemia. Interestingly, CD28-KO mice were unable to produce anti-T. cruzi IgG antibodies but presented moderate tissue pathology and managed to control the infection. Thus, differently from infections with high virulence parasites, neither IgG, NO nor CD28-mediated signalling are essential for the non-sterile control of Sylvio X10/4 parasites.
Sujet(s)
Spécificité des anticorps , Cardiomyopathie associée à la maladie de Chagas/immunologie , Immunoglobuline G , Interféron gamma/physiologie , Monoxyde d'azote , Trypanosoma cruzi/immunologie , Trypanosoma cruzi/pathogénicité , Animaux , Lignée cellulaire , Cardiomyopathie associée à la maladie de Chagas/génétique , Cardiomyopathie associée à la maladie de Chagas/métabolisme , Modèles animaux de maladie humaine , Femelle , Immunoglobuline G/physiologie , Souris , Souris de lignée BALB C , Souris de lignée C3H , Souris de lignée C57BL , Souris knockout , Souris nude , Monoxyde d'azote/physiologie , Virulence/génétique , Virulence/immunologieRÉSUMÉ
This study examines patterns of growth and nutritional status of indigenous Tsimane' children under 9 years of age (n = 199 boys and 210 girls), based on a cross-sectional sample from 58 villages from the Beni Deparment of lowland Bolivia. Compared with US children, Tsimane' children are quite short, with linear growth tracking at or below the US 5th centile in both sexes. The prevalence of low height-for-age ("stunting;" HA Z-scores
Sujet(s)
Mensurations corporelles/ethnologie , Mensurations corporelles/physiologie , Développement de l'enfant/physiologie , Phénomènes physiologiques nutritionnels chez l'enfant/physiologie , Indien Amérique Sud/statistiques et données numériques , Répartition par âge , Bolivie/épidémiologie , Enfant , Enfant d'âge préscolaire , Études transversales , Femelle , Troubles de la croissance/épidémiologie , Humains , Nourrisson , Nouveau-né , Mâle , Évaluation de l'état nutritionnel , État nutritionnel , Prévalence , Répartition par sexe , Maigreur/épidémiologieRÉSUMÉ
Los presentes documentos correpondientes a la consultoría sobre el plan quinquenal del PAI 2001-2005, constituye constituye un plan de acción realizado para los nueve departamentos de Bolivia con el fin de lograr mayor cobertura de inmunización a nivel nacional, brindando estrategias para mejorar la cobertura de vacunación, además se añade a estos documentos el inventario de cadena de frío también realizado en los nueve departamentos