Participation of interferon type I during canine parvovirus infection.

Canine parvovirus (CPV) is a single-stranded DNA virus that causes severe and fatal gastrointestinal diseases in dogs. CPV has developed several strategies to evade innate immune response mediated by type I interferons (IFN-I) to achieve a successful infection. The aim of this work was to evaluate the capability of CVP-2c to evade the IFN-I mediated response in infected cells. To establish the role of this response, the gene expression of interferon ß (IFNß), IFIT1, IFIT3, MAVS, and STING were estimated in MDCK cells infected with CPV-2c. Viral replication and gene expression was evaluated by quantitative PCR, also, a treatment with IFN-I (interferon omega) was included to confirm the role of IFN-I during CPV infection. The results revealed that CPV-2c infection stimulates the expression of IFNß moderately, in these cells. Due to low IFNß induction, the IFIT1 and IFIT3 expression were also low, and therefore CPV-2c was able to replicate in these cells. However, when the cells were treated with exogenous IFN-I, the IFNß expression was higher, leading to an increased gene expression of IFIT1 and IFIT3, responsible for antiviral control. The overexpression of these proteins reduced the expression of NS1 and VP2 viral genes and hence viral replication. MAVS and STING expression on infected cells showed a mild increase compared to IFNß, suggesting that the viral infection could partially modify its expression. All results obtained in this study showed that during CPV-2c infection in MDCK cells, the IFNß expression was altered since this cytokine is one of the most critical factors for the control and inhibition of viral replication.

Evaluation of intracellular survival of Campylobacter fetus subsp. fetus in bovine endometrial cells by qPCR.

BACKGROUND: Campylobacter fetus subsp. fetus is the causal agent of sporadic abortion and infertility in bovines that produces economic losses in livestock. AIMS: This study evaluates the capability of C. fetus subsp. fetus to invade and survive in bovine endometrial epithelial cells and attempts to describe a pathogenic mechanism of this microorganism. METHODS: Primary culture of bovine endometrial epithelial cells was challenged with C. fetus subsp. fetus. Intracellular bacteria, represented by the number of genomic copies (g.c.) were quantified at 0, 2, 4, 10, and 24 hours post-infection (h.p.i.), by quantitative polymerase chain reaction (qPCR). The presence of intracellular bacteria was evaluated by immunofluorescence and immunohistochemistry. RESULTS: The results showed that only viable C. fetus subsp. fetus could invade endometrial cells. The g.c. number in assays with viable C. fetus subsp. fetus reached an average value of 656 g.c., remained constant until 4 h.p.i., then decreased to 100 g.c, at 24 h.p.i. In assays with non-viable microorganisms, the average value of g.c. was less than 1 g.c. and never changed. The intracellular presence of this bacteria was confirmed at 2 h.p.i. by immunofluorescence and immunohistochemistry. CONCLUSION: The results suggest that only C. fetus subsp. fetus viable can invade bovine endometrial epithelial cells but will not replicate in them, indicating that the endometrial cells do not represent a replication niche for this pathogen. Nonetheless, this invasion capability suggests that this type of cell could be employed by the pathogen to spread to other tissues.