Escherichia coli Vacuolating Factor (ECVF) como fator associado a celulite aviáriaEssas proteínas podem estar envolvidas na interação de ECVF com a célula, durante a indução de citotoxicidade que leva ao dano tecidual. Nossos resultados, apoiados por dados de estudos anteriores, permitem sugerir um importante papel de ECVF na patogenia da celulite aviária, podendo contribuir para elucidação do mecanismo de desenvolvimento da doença.
Palavras-chave: Escherichia coli patogênica aviária (APEC). Escherichia coliVacuolating Factor (ECVF). Celulite aviária. Escherichia coli isolated from cellulitis lesions in broiler chickens produce a citotoxin, called ECVF (Escherichia coli Vacuolating Factor), which causes intense cytoplasm vacuolization in cells of avian origin, but not in mammalian cells. The importance of ECVF in the pathogenesis of avian cellulitis was assessed by citotoxicity assays in cell culture and in vivo assays. Purified ECVF was inoculated subcutaneously in broiler chickens, and induced alterations on subcutaneous, adipose and connective tissues, with signs of inflammation and infiltrates of heterophile, lymphocytes and plasma cells. In citotoxicity assays, we verified that ECVF induced alterations at cytoskeleton and nucleus of avian fibroblasts, such as apoptosis, time-dependent. In transmission electronic microscopy, we verified that ECVF induced citoplasmic and nuclear alterations, which can affect cellular metabolism directly, including chromatin condensation and nuclear fragmentation, intense cytoplasm vacuolization, and disorganization of cytoskeleton and organelles. It was also verified the interaction of ECVF with proteins of avian cells, instead of those from mammalian cells, suggesting the specificity of this toxin to this cells. These proteins may be involved in the interaction of ECVF with the cell, during the induction of citotoxicity, which will lead to the tissue damage. Our results, supported by data from previous studies, suggest an important role of ECVF in the pathogenesis of avian cellulitis, which may contribute to the elucidation of the mechanism of disease development.