ABSTRACT

The function of neutrophils and innate lymphoid cells (ILCs) in viral infections has been established with most of the studies conducted in mice and humans but rarely in other species including cattle. The role of neutrophil extracellular traps (NETs) has also been evaluated in viral infections but due to excess tissue damage that maybe caused by NETs, further studies are needed to reveal a therapeutic target. ILCs have also been identified in viral conditions affecting mice and humans but currently very little is known about the isolation and identification of ILCs in bovine lung tissue. Here, we describe a method for sample collection, cell preparation and flow cytometric analysis of bovine lung samples to identify bovine ILCs. This study aims to evaluate the effects of the treatments, FPI and ibuprofen a cyclooxygenase-2 inhibitor, on the innate immune response, focusing mainly on NETs and ILCs to test if their populations change with the different treatment protocols. We conducted a randomized placebo-controlled trial of ibuprofen, FPI, or as a dual therapy initiated at 3 or 5 days after experimental infection with BRSV in 36 five to six-week-old Holstein calves (Bos Taurus). Lung tissue samples were collected and stained with antibodies conjugated with fluorescence dyes to visualize and quantify the NETs in situ. There were significantly fewer NETs in the lung tissue from calves that were given ibuprofen and both ibuprofen and fusion protein inhibitor from day 3 post infection compared to the placebo (no treatment) group. The last chapter of this dissertation depicts the experiments carried out in an attempt to identify ILCs from the lung samples. This is the preliminary analysis of ILCs, and further studies will be performed to characterize the cells and assess their function.