Date Awarded


Document Type


Degree Name

Master of Science (M.Sc.)




Patty Zwollo

Committee Member

Lizabeth Allison

Committee Member

Matthew Wawersik


During the return journey to their spawning grounds, sockeye salmon are exposed to various pathogens and undergo major endocrine changes. Little is known about how these changes affect their immune system. The immune system of salmon is similar to mammals; myeloid lineage cells provide the first response to infection and B lineage cells protect against specific pathogens. After activation by pathogen, B cells may differentiate into long-lived plasma cells (LLPCs) in the anterior kidney, where they can survive for years, continuously secreting protective antibody. This research focused on salmon from two rivers, the Kenai and the Copper River, and characterized changes in anterior kidney immune cell abundance during their journey and at various spawning sites. Additionally, possible correlations with relative spleen size, distance traveled, water temperature, and infections with Infectious Hematopoietic Necrosis Virus were investigated. Flow cytometry was used to analyze the abundance of B cells, LLPCs, and myeloid lineage cells in the anterior kidney. Quantitative PCR was used to determine IHNV load in the spleen. During the Kenai River Run, myeloid cells and activated B cells transiently decreased while (im)mature B cells, IgM+ B cells, and LLPCs transiently increased. The changes in myeloid cells, IgM+ B cells, and LLPCs were conserved at the Kenai and Copper River Runs. Analysis indicated that a larger spleen index correlated with immune system activation and a lower prevalence of IHNV. These findings provide a better understanding of immune changes during spawning in sockeye salmon.



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