Kinome analysis of cattle peripheral lymph nodes to elucidate differential response to Salmonella spp

Authors: ARSENAULT, RYAN - University Of Delaware; BROWN, TYSON - Former ARS Employee; EDRINGTON, THOMAS - Former ARS Employee; NISBET, DAVID - Retired ARS Employee

Submitted to: Microorganisms
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2022
Publication Date: 1/7/2022
Citation: Arsenault, R.J., Brown, T.R., Edrington, T.S., Nisbet, D.J. 2022. Kinome analysis of cattle peripheral lymph nodes to elucidate differential response to Salmonella spp. Microorganisms. 10(1). Article 120. https://doi.org/10.3390/microorganisms10010120.
DOI: https://doi.org/10.3390/microorganisms10010120

Interpretive Summary: Salmonella are foodborne pathogens that can be contained within the lymph nodes of cattle, which represents a significant source of contamination of ground beef. We report the results from a study assessing the relation of specific enzymes in the lymph nodes of cattle to further our understanding of Salmonella within these reservoirs of infection. For the purpose of this research, multiple comparisons of lymph nodes were made to include: nodes from feedlot cattle that were infected with Salmonella 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 finally the lymph nodes from cattle experimentally-inoculated with Salmonella versus naturally-infected animals. The first comparison of Salmonella-positive and negative lymph nodes found that, considering the specific enzymes studied in these animals, the major distinguishing difference was not the presence or absence of Salmonella in the lymph node but the amount of Salmonella residing in the node. Further, the majority of enzymatic pathways activated were directly related to immune responses, thus Salmonella within the lymph nodes activates the immune system in that node. Results from the comparison of feedlot cattle and cull dairy cows suggests that a Salmonella negative animal, regardless of type, has a more consistent enzyme profile than that of a Salmonella-positive animal, and that the differences between feedlot and cull dairy cattle are only pronounced when the lymph nodes contain Salmonella. Lymph nodes collected in the winter showed a much more consistent enzyme profile, regardless of Salmonella status, suggesting that in the winter these cattle are similar, and this is not affected by the presence of Salmonella, whereas significant variability among enzymes was observed for lymph nodes collected in the summer. The most distinct clustering of enzymes observed in this study was related to how the animal was infected with Salmonella. There were significant differences in the activation state of the immune response molecules 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 Salmonella within cattle, and specifically within the lymph nodes which act as a reservoir of infection, will ultimately help livestock producers design effective pre-harvest intervention strategies to prevent contamination events thereby producing safe and wholesome beef for the American consumer.

Technical Abstract: Salmonella, contained within the peripheral lymph nodes (PLN) 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 Salmonella within these PLN. 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 Salmonella 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 finally PLN from cattle experimentally-inoculated with Salmonella versus naturally-infected animals. The first comparison of Salmonella-positive and negative PLN found that considering the kinotypes for these animals, the major distinguishing difference was not the presence or absence of Salmonella in the PLN but the concentration. Further, the majority of pathways activated were directly related to immune responses including innate immunity, thus Salmonella within the PLN activates the immune system in that node. Results from the comparison of feedlot cattle and cull dairy cows suggests that a Salmonella negative animal, regardless of type, has a more consistent kinome profile than that of a Salmonella-positive animal and that the differences between feedlot and cull dairy cattle are only pronounced when the PLN are Salmonella positive. PLN collected in the winter showed a much more consistent kinome profile, regardless of Salmonella status, suggesting that in the winter these cattle are similar, and this is not affected by the presence of Salmonella, whereas significant variability among kinotypes was observed for PLN collected in the summer. The most distinct clustering of kinotypes observed in this study was related to how the animal was infected with Salmonella.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 Salmonella within cattle, and specifically within the PLN, will ultimately help design effective pre-harvest intervention strategies as well as appropriate experimentation to validate those technologies.