CONICET | Buscador de Institutos y Recursos Humanos

Abstract Text: Background: Brucella canis is an important cause of abortion in dogs, but the pathogenic mechanisms involved are unknown. We evaluated the ability of B. canis to infect canine trophoblastic cells and analyzed the inflammatory immune response triggered by infection or interaction with infected phagocytes.Methods: trophoblastic cells were isolated from term placenta of healthy female dogs (obtained by Csection) and were characterized by their expression of cytokeratin 7. Neutrophils were isolated from peripheral blood of healthy dogs. Trophoblasts were infected with B. canis for 48 h for intracellular colony forming units (CFU) determination and measurement of LDH (lactate dehydrogenase) activity. Neutrophils were infected with B. canis for 24 h and conditioned media were used to stimulate uninfected trophoblasts. Proinflammatory cytokines were measured in all culture supernatants. Results: Isolated canine trophoblasts were positive for cytokeratin 7 staining. B. canis CFU counts inside trophoblasts increased significantly between 24 and 48 h post infection. LDH levels remained similar between uninfected and infected cells. Both IL-8 and RANTES levels were significantly increased in infected trophoblasts as compared to uninfected cells, whereas IL-6 remained undetectable. Trophoblasts also increased their secretion of IL-8 and RANTES upon stimulation with conditioned media from infected neutrophils.Conclusions: B. canis infects and replicates in canine trophoblasts without inducing cytotoxicity. In response to B. canis infection or factors produced by infected neutrophils trophoblasts produce inflammatory mediators including IL-8 and RANTES (chemoattractants for neutrophils and several leukocytic populations, respectively). The inflammatory response induced by these chemokines may contribute to fetal miscarriage