Avaliação do papel do Fator de Inibição de Migração de Macrófagos (MIF) durante a infecção por Neospora caninum

Abstract

Neospora caninum is a protozoan of the phylum Apicomplexa, distributed worldwide, and relevant due to induction of abortions in bovine leading to considerable economic loss. MIF is a cytokine known to be involved in response against intracellular protozoa, which is produced by several immune cells, and it is found intracellularly preformed, turning this cytokine an important factor in acute inflammatory response, exhibiting a central role in innate immunity. Considering the lack of information about the role of MIF in this specific model, the present study aimed to evaluate the relevance of this cytokine during an infection by N. caninum. We therefore analysed the cytokine production and phenotype induced by itself, using wild type (WT) and genetically deficient in MIF (MIF-/-) C57BL/6 mice, infected with 5x106 tachyzoites of Nc-Liv. Based on this infection it was possible to observe an acute production of MIF in cells and peritoneal cavity fluids, spleen and lungs. We also observed production in serum after 30 days of infection. Additionally, it was demonstrated that MIF-/- mice possesses decreased parasitism during acute and chronic phases of infection. Moreover, it was observed an elevated production of TNF-α and NO and increased pulmonary inflammation in those animals as well as a slight increase in survival and recovery of body weight in comparison to WT mice. It was found that TNF-α is involved in the secretion of MIF, unlike the adapter molecules MyD88 and TRIF. In sum, it is possible to conclude that MIF presents a relevant modulatory role during the establishment of infection by N. caninum.