Biological properties and diverse cytokine profiles followed by in vitro and in vivo infections with LSDV strain isolated in first outbreaks in Vietnam.

Preliminary information about LSD virus isolated from the first outbreaks in Vietnam has been reported by our laboratory. In the current study, LSDV strain, LSDV/Vietnam/Langson/HL01(HL01) was further analyzed to provide a better understanding of this viral pathogen. HL01 LSDV strain was propagated at MOI 0.01 in MDBK cells and then given to cattle at dose of 106.5 TCID50/ml (2ml/animal). The production of proinflammatory (IFN-γ, IL-1α, and TNF-α) and anti-inflammatory (IL-6, IL-10, and TGF-ß1) cytokines were measured by real-time PCR, both In vitro and In vivo. The results demonstrated that HL01 strain caused the typical signs of LSD and LSDV In vitro and In vivo, respectively suggesting a virulent field LSDV strain. Additionally, different cytokine profiles were observed in these In vitro and In vivo studies. In MDBK cells, different cytokines profiles were observed in two phases: in the early phase, the expression levels of all examined cytokines were significantly increased at 6 h (p < 0.05). In the later phase, the peak levels of the cytokine secretion were recognized from 72 to 96 h, with the exception of IL-1α when compared to controls. In cattle, the expression levels of all six cytokines were significantly higher at day 7 following LSDV challenge (p < 0.05) when compared to controls, especially expression levels of TGF-ß1 and IL-10. These findings suggest the important roles of these cytokines in protection against LSDV infections. Additionally, the data from diverse cytokine profiles followed by this LSDV strain challenge provides key understanding of the underlying cellular immune mechanisms in the host against LSDV infection In vitro and In vivo.