Níveis de eosinófilos na fase aguda da doença de Chagas experimental

Eosinophil dynamics, in bone marrow, blood and peritoneal exudate, of resistant C57B1/6 (C57) and susceptible A/Snell (A/Sn) mice was comparatively studied during the acute phase of infection by Trypanosoma cruzi Y strain. A decline was observed in bone marrow eosinophil levels in A/Sn, but not in C57 mice, soon after infection, those of the former remaining significantly below those of the latter up to the 4th day of infection. Bone marrow eosinophil levels of C57 mice declined subsequently to levels comparable to those of A/Sn mice, the number of these cells in this compartment remaining 50% those of non infected controls, in both strains, up to the end of the experiment on the 14th day of infection. The fluctuations in eosinophil levels in blood and peritoneal space were similar in both mice strains studied. Concomitantly with depletion of eosinophils in the marrow, depletion in blood and a marked rise of these cells in the peritoneal space, initial site of infection, occurred in both strains. The difference in eosinophil bone marrow levels, between C57 and A/Sn mice, observed in the first four days of infection, suggests a higher eosinopoiesis capacity of the former in this period, which might contribute to their higher resistance to T. cruzi infection.A dinâmica de eosinófilos, na medula óssea, sangue e exsudato peritoneal, de uma linhagem de camundongos resistente (C57B1/6) e de uma susceptível (A/Snell) foi comparativamente estudada durante a fase aguda da infecção com a cepa Y do Trypanosoma cruzi. Foi observada uma queda nos níveis de eosinófilos da medula óssea nos camundongos A/Sn, mas não nos C57, logo após a infecção, os dos primeiros permanecendo significativamente abaixo dos níveis dos últimos até o 4? dia de infecção. Os níveis de eosinófilos da medula óssea nos camundongos C57 caíram subseqüentemente a níveis próximos aos dos camundongos A/Sn, o número destas células neste compartimento permanecendo em torno de 50% daqueles dos controles não infectados, em ambas as linhagens, até o término do experimento, no 14º dia. As flutuações nos níveis de eosinófilos no sangue e cavidade peritoneal foram semelhantes nas duas linhagens de camundongos estudadas. Concomitantemente com a depleção na medula, ocorreram depleção destas células no sangue e significativo aumento na cavidade peritoneal, foco inicial da infecção, em ambas linhagens de camundongos. A diferença nos níveis de eosinófilos da medula óssea entre os camundongos C57 e A/Sn, observada nos 4 primeiros dias de infecção, sugere uma maior capacidade de eosinopoiese dos primeiros nesse período, o que poderia contribuir para sua maior resistência à infecção pelo T. cruzi

Eosinophil levels in the acute phase of experimental chagas' disease

Eosinophil dynamics, in bone marrow, blood and peritoneal exudate, of resistant C57B1/6 (C57) and susceptible A/Snell (A/Sn) mice was comparatively studied during the acute phase of infection by Trypanosoma cruzi Y strain. A decline was observed in bone marrow eosinophil levels in A/Sn, but not in C57 mice, soon after infection, those of the former remaining significantly below those of the latter up to the 4th day of infection. Bone marrow eosinophil levels of C57 mice declined subsequently to levels comparable to those of A/Sn mice, the number of these cells in this compartment remaining 50% those of non infected controls, in both strains, up to the end of the experiment on the 14th day of infection. The fluctuations in eosinophil levels in blood and peritoneal space were similar in both mice strains studied. Concomitantly with depletion of eosinophils in the marrow, depletion in blood and a marked rise of these cells in the peritoneal space, initial site of infection, occurred in both strains. The difference in eosinophil bone marrow levels, between C57 and A/Sn mice, observed in the first four days of infection, suggests a higher eosinopoiesis capacity of the former in this period, which might contribute to their higher resistance to T. cruzi infection

Trypanosoma cruzi: curso da infecção em camundongos depletados de plaquetas

O efeito do esgotamento de plaquetas sobre o curso da infecção pelo Trypanosoma cruzi em camundongos BALB/c foi estudado. A trombocitopenia foi provocada por inoculação de IgG de coelho anti-plaquetas durante a fase parasitêmica da infecção. O número de parasitas no sangue dos camundongos tratados com IgG anti-plaquetas foi significantemente maior que aquele dos controles não tratados, no período de maior parasitemia. A mortalidade cumulativa dos camundongos esgotados de plaquetas foi consistente mas não significativamente maior que a dos controles até o 32º dia de infecção; do 33º dia em diante elas foram equivalentes, nenhuma morte ocorrendo a partir de então, até o 60º dia, quando as observações foram interrompidas. Estes resultados sugerem que as plaquetas participam dos mecanismos de remoção dos parasitas da circulação, mas que não desempenham um papel efetivo nos mecanismos de defesa contra o T. cruzi na fase aguda da infecção.The effect of platelet depletion on the course of Trypanosoma cruzi infection in BALB/c mice was investigated. Thrombocytopenia was achieved by inoculation of rabbit anti-platelet IgG during the parasitemic phase of the infection. The number of parasites in the blood of anti-platelet IgG treated was significantly higher than that of non-treated control mice, during the phase of high parasitemia. Cumulative mortality of platelet-depleted mice was consistently but not significantly higher than that of control mice up to the 32nd day of infection; from the 33rd day on they were equivalent, no mortalities occurring from then on, until observations were discontinued on the 60th day. These results suggest that platelets participate of the mechanisms of parasites removal from the bloodstream, but do not have an effective role in the mechanisms of defence against T. cruzi, during the acute phase of infection

Detection of circulating polysaccharide antigen of Schistosoma mansoni in hamster sera by crossed immunoelectrophoresis

Crossed immunoelectrophoresis (IEC) was used for detection of free and complexed circulating polisaccharide anodic antigen (AgCA) of Schistosoma mansoni in sera of infected hamsters. An attempt was also done to detect AgCA in human sera from patients infected with S. mansoni. The conditions for isolation and detection of complexed AgCA were established. The sensitivity of IEC was increased by incorporation of 2% polyethylene glicol (PEG) to the agarose and by maintaining the system at 4°C during the electrophoretic run. Free AgCA was detected in 12 and the complexed in 30 of the 37 hamsters sera analysed. Correlation between AgCA (free and complexed) and the parasite load was observed. AgCA was not detected, under the experimental conditions used, in human sera from 7 patients in the acute and 23 in the chronic phase of infection