Development and pathology of Fasciola hepatica in CCL3-deficient mice

Fasciola hepatica is a parasitic helminth that predominantly infects the liver and bile ducts of cattle and causes great losses of cattle production in the southern and southeastern regions of Brazil. The generation of liver lesions and the consequent inflammatory responses are intimately related to the migration of this parasite. The CC-group of chemokines plays a crucial role in the attraction of several cell types and in the recruitment of additional macrophages to an inflammatory focus in numerous diseases. In order to evaluate the role of CCL3 in the development of F. hepatica, we compared parasitological and pathological parameters in C57Bl/6J mice that were assigned to one of two experimental groups: the first group contained CCL3-producing mice (CCL3(+/+) mice) and the other group contained mice that were genetically deficient in CCL3 production (CCL3(-/-) mice). The mortality rate in the CCL3 non-deficient group was higher than of the deficient animals. In most animals from both experimental groups, the necropsied animals contained hemorrhages in their abdominal cavities. In the genetically modified animals, the lesioned liver areas were less extensive and presented focal and sub-capsular lesions. This work demonstrates that the development of F. hepatica is not affected by the absence of CCL3.