Martins-Souza R L, Pereira C A J, Coelho P M Z, Negrão-Corrêa D
Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Presidente Antônio Carlos 6627, Campus Pampulha, 31270-901, Belo Horizonte, Minas Gerais, Brazil.
Parasitol Res. 2003 Dec;91(6):500-7. doi: 10.1007/s00436-003-0985-4. Epub 2003 Oct 7.
The present work demonstrates that silica treatment represents a suitable in vivo method to evaluate the role of host phagocytic hemocytes in the mechanisms of resistance to parasitic infection. Silica inoculation into Biomphalaria tenagophila snail induced a significant reduction in the circulating hemolymph granulocytes in both strains tested (Taim and Cabo Frio). The granulocyte reduction was accompanied by a significant increase in the number of circulating dead cells. In B. tenagophila Cabo Frio, silica treatment enhanced snail susceptibility to Schistosoma mansoni, shortening the intramolluskan phase of the parasite and increasing the number of sporocysts and cercariae produced. In B. tenagophila Taim, the same treatment did not abrogate natural resistance to S. mansoni reported for this snail strain. These in vivo results demonstrate that macrophage-like granulocytes are involved in the mechanism of S. mansoni sporocyst destruction in Cabo Frio snails and suggest that another, different mechanism may be responsible to the natural resistance of B. tenagophila Taim.
目前的研究表明，二氧化硅处理是一种合适的体内方法，可用于评估宿主吞噬血细胞在抵抗寄生虫感染机制中的作用。将二氧化硅接种到嗜气管双脐螺中，在测试的两个品系（泰姆和卡波弗里奥）中均导致循环血淋巴粒细胞显著减少。粒细胞减少伴随着循环死细胞数量的显著增加。在嗜气管双脐螺卡波弗里奥品系中，二氧化硅处理增强了蜗牛对曼氏血吸虫的易感性，缩短了寄生虫在螺体内的阶段，并增加了产生的子孢蚴和尾蚴数量。在嗜气管双脐螺泰姆品系中，相同处理并未消除该蜗牛品系对曼氏血吸虫的天然抗性。这些体内结果表明，巨噬细胞样粒细胞参与了卡波弗里奥蜗牛中曼氏血吸虫子孢蚴的破坏机制，并表明可能存在另一种不同的机制导致嗜气管双脐螺泰姆品系的天然抗性。
