Kinome Analysis of Cattle Peripheral Lymph Nodes to Elucidate Differential Response to Salmonella spp

spp., contained within the peripheral lymph nodes (PLNs) of cattle, represents a significant source of contamination of ground beef. Herein is the first report where species-specific kinome peptide arrays designed for bovine biology were used to further the understanding of spp. within these PLNs. For the purpose of this research, multiple comparisons of sub-iliac lymph nodes were made to include nodes from feedlot cattle that were infected with spp. to those that were non-infected; seasonal differences in feedlot cattle harvested in either August or January; cull dairy cows compared to feedlot cattle; and PLNs from cattle experimentally inoculated with spp. versus naturally infected animals. The first comparison of -positive and -negative PLNs found that considering the kinotypes for these animals, the major distinguishing difference was not the presence or absence of spp. in the PLNs but the concentration. Further, the majority of pathways activated were directly related to immune responses including innate immunity, thus spp. within the PLNs activates the immune system in that node. Results from the comparison of feedlot cattle and cull dairy cows suggests that a spp.-negative animal, regardless of type, has a more consistent kinome profile than that of a spp.-positive animal and that the differences between feedlot and cull dairy cattle are only pronounced when the PLNs are spp. positive. PLNs collected in the winter showed a much more consistent kinome profile, regardless of status, suggesting that in the winter these cattle are similar, and this is not affected by the presence of spp., whereas significant variability among kinotypes was observed for PLNs collected in the summer. The most distinct clustering of kinotypes observed in this study was related to how the animal was infected with spp. There were significant differences in the phosphorylation state of the immune response peptides between experimentally and naturally infected animals, suggesting that the immune system is activated in a significantly different manner when comparing these routes of infection. Increasing our understanding of spp. within cattle, and specifically within the PLNs, will ultimately help design effective pre-harvest intervention strategies as well as appropriate experimentation to validate those technologies.