Lumpy Skin Disease virus (LSDV) is an important disease of cattle, causing significant economic losses where outbreaks have occurred. LSDV is spread by blood-feeding insects and since 2017 has rapidly spread throughout Asia and in 2022 was detected in Indonesia. While Australia is currently disease free, it is estimated that an incursion will result in a loss of greater than $8 billion in revenue within the first year. Cattle infected with LSDV generally have a low mortality rate (<10%), however morbidity is moderate to high (2 – 45%). With detection of LSDV in our neighbouring pacific countries, the risk of incursion into Australia is higher than ever.
Knowledge regarding the animal host’s innate and cellular immune response is currently limited. We have conducted a longitudinal analysis of six experimentally LSDV-infected cattle to help elucidate changes in the host immune response.
Cytokine analysis of serum samples has revealed an increase in inflammatory cytokines IFN-g and TNF-a and the regulatory cytokine IL-10, as well as increases in the chemokines CCL2, CXLX10 and MIP1beta.
Immune cell changes were also measured in whole blood by flow cytometry over time. We were able to identify natural killer (NK) cells, dendritic cells (DC), classical and non-classical monocytes, B cells, CD4+ T cells, CD8+ T cells and gamma delta T cells, which have never before been examined during LSDV infection. The expression of activation markers CD25 and CD69 and co-stimulatory molecules CD80 and CD86 was also examined over 28 days post viral challenge.
The cell mediated response to LSDV was also assessed using an IFN-gamma release assay (IGRA), where whole blood from the experimentally infected cattle was re-stimulated with LSDV in vitro and IFN-y released into the plasma was measured.
Overall, this research provides highly unique and novel information about the host immune response to this important transboundary disease, with ACDP-CSIRO being the only certified facility in Australia capable of undertaking such work.