title: Sockeye salmon retain immunoglobulin-secreting plasma cells throughout their spawning journey and post-spawning.
abstract: Antibody-producing plasma cells are a major source of protective immunity in vertebrates, including salmon. During the spawning phase, salmon undergo drastic, hormonally driven changes in their physiology, including elevated levels of cortisol, which are known to suppress the immune system. As adult fish need to survive their long journey to the spawning grounds, we hypothesized that humoral immunity, in the form of IgM-secreting plasma cells, remains functional until post-spawning. This was investigated by measuring changes in membrane and secreted immunoglobulin heavy chain mu and Pax5 transcripts in spleen and kidney from migrating sockeye salmon, using real-time qPCR. As an additional measurement, the abundance of developing B, mature B, and plasma cells was determined in spawning fish, using flow cytometry. Immune tissue samples were collected from fish from the Kenai River drainage and Main Bay, Prince William Sound. Our results reveal that spawning fish express high levels of secreted heavy chain mu transcripts in their spleen and anterior kidney throughout the spawning journey. Furthermore, we show that IgM-secreting PCs (HCmu++/Pax5-) remain abundant in anterior kidney and spleen of post-spawning sockeye salmon, with a concomitant loss in developing B cells (HCmu-/Pax5+). This suggests that successful spawners retain their PCs throughout the spawning journey and post-spawning.
authors: Department of Biology, The College of William and Mary, Williamsburg, VA 23185, United States.
authors: Jonathan
authors: J
authors: Schouten
authors: Terri
authors: T
authors: Clister
authors: Amber
authors: A
authors: Bruce
authors: Lidia
authors: L
authors: Epp
authors: Patty
authors: P
authors: Zwollo
mesh_terms: D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D005260:Female; D029941:Fish Proteins / Q000378:metabolism; D060226:Head Kidney / Q000378:metabolism; D007143:Immunoglobulin Heavy Chains / Q000378:metabolism; D007075:Immunoglobulin M / Q000378:metabolism; D008297:Male; D009928:Organ Specificity; D051757:PAX5 Transcription Factor / Q000235:genetics / Q000378:metabolism; D010950:Plasma Cells / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012098:Reproduction / Q000276:immunology; D045483:Rivers; D012474:Salmon / Q000276:immunology* / Q000378:metabolism; D013154:Spleen / Q000378:metabolism
chemical_list: D029941:Fish Proteins; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M; D051757:PAX5 Transcription Factor; D012333:RNA, Messenger