Immune cells in rainbow trout Oncorhynchus mykiss comprise granulocytes (neutrophils, basophils and eosinophils), macrophages/monocytes and lymphocytes (B- and T-cells). These cellular elements occur early during the ...Immune cells in rainbow trout Oncorhynchus mykiss comprise granulocytes (neutrophils, basophils and eosinophils), macrophages/monocytes and lymphocytes (B- and T-cells). These cellular elements occur early during the ontogenetic development of trout and allow both innate and adaptive responses towards an antigen to be initiated even in fry. The number of leukocytes in individual fish at different developmental stages is likely to influence the capacity of the fish to respond simultaneously to several antigens (pathogens and vaccine components). This parameter may therefore be crucial for both wild and cultured fish and we show that the size of the leukocyte population increase exponentially with body size of rainbow trout. Four groups (5 fish/ group) of naive rainbow trout (Oncorhynchus mykiss) with a mean body weight of 2-4 g (group I), 4-6 g (group II), 25-30 g (group III), and 650-780 g (group IV) were investigated. The number of lymphocytes was generally higher in head kidney compared to blood and spleen but they dominated in all samples (blood, head kidney, and spleen) and their numbers increased exponentially with fish size. Percentages of lymphocytes in relation to neutrophils and macrophages were higher in spleen (98%-99%) compared to blood and head kidney in all groups. Fish fry is therefore equipped to respond specifically against one or a few vaccine antigens but the capacity to raise protective responses against a repertoire of pathogens may be limited until the larger fingerling stage has been reached. The implications for vaccination of early fry are discussed.展开更多
Crohn’s disease and ulcerative colitis—inflammatory bowel diseases (IBD)—are chronic conditions with an inadequately understood pathogenesis. Employing a set of novel molecular markers in a gene expression assay (q...Crohn’s disease and ulcerative colitis—inflammatory bowel diseases (IBD)—are chronic conditions with an inadequately understood pathogenesis. Employing a set of novel molecular markers in a gene expression assay (qPCR), we have used adult zebrafish to investigate two acute inflammatory models, induced by the haptenizing agents oxazolone and TNBS. In addition, goblet cell dynamics in the scales and intestine and 5-HT (serotonin) in intestinal tissues were investigated through optical projection tomography. Gene expression studies revealed a distinct and significant upregulation of proinflammatory cytokines, acute-phase reactants and metalloprotease 9 in both chemical models, primarily after 72 hours. In comparison, transcription factors and cytokines associated with Th1 and Th17 (Crohn’s) and Th2 (ulcerative colitis) were mainly not affected in this acute setting. However, elevated transcript levels were detected in Foxp3, IL-10 and T-bet, which are linked with tolerance and Tregs in mammals. Goblet cells in scales were depleted in both chemical models and in the intestine of oxazolone-treated fish. A marked 5-HT signal was noted in intestinal tissue of some chemically treated zebrafish. In conclusion, a distinct acute inflammatory reaction was induced in both chemical models. Further, oxazolone and TNBS did not result in clear-cut Th2 and Th1/Th17 pathway signaling at this early timepoint, but the applied molecular tools may provide further insight to the IBD pathogenesis and translational value of the IBD zebrafish model.展开更多
文摘Immune cells in rainbow trout Oncorhynchus mykiss comprise granulocytes (neutrophils, basophils and eosinophils), macrophages/monocytes and lymphocytes (B- and T-cells). These cellular elements occur early during the ontogenetic development of trout and allow both innate and adaptive responses towards an antigen to be initiated even in fry. The number of leukocytes in individual fish at different developmental stages is likely to influence the capacity of the fish to respond simultaneously to several antigens (pathogens and vaccine components). This parameter may therefore be crucial for both wild and cultured fish and we show that the size of the leukocyte population increase exponentially with body size of rainbow trout. Four groups (5 fish/ group) of naive rainbow trout (Oncorhynchus mykiss) with a mean body weight of 2-4 g (group I), 4-6 g (group II), 25-30 g (group III), and 650-780 g (group IV) were investigated. The number of lymphocytes was generally higher in head kidney compared to blood and spleen but they dominated in all samples (blood, head kidney, and spleen) and their numbers increased exponentially with fish size. Percentages of lymphocytes in relation to neutrophils and macrophages were higher in spleen (98%-99%) compared to blood and head kidney in all groups. Fish fry is therefore equipped to respond specifically against one or a few vaccine antigens but the capacity to raise protective responses against a repertoire of pathogens may be limited until the larger fingerling stage has been reached. The implications for vaccination of early fry are discussed.
文摘Crohn’s disease and ulcerative colitis—inflammatory bowel diseases (IBD)—are chronic conditions with an inadequately understood pathogenesis. Employing a set of novel molecular markers in a gene expression assay (qPCR), we have used adult zebrafish to investigate two acute inflammatory models, induced by the haptenizing agents oxazolone and TNBS. In addition, goblet cell dynamics in the scales and intestine and 5-HT (serotonin) in intestinal tissues were investigated through optical projection tomography. Gene expression studies revealed a distinct and significant upregulation of proinflammatory cytokines, acute-phase reactants and metalloprotease 9 in both chemical models, primarily after 72 hours. In comparison, transcription factors and cytokines associated with Th1 and Th17 (Crohn’s) and Th2 (ulcerative colitis) were mainly not affected in this acute setting. However, elevated transcript levels were detected in Foxp3, IL-10 and T-bet, which are linked with tolerance and Tregs in mammals. Goblet cells in scales were depleted in both chemical models and in the intestine of oxazolone-treated fish. A marked 5-HT signal was noted in intestinal tissue of some chemically treated zebrafish. In conclusion, a distinct acute inflammatory reaction was induced in both chemical models. Further, oxazolone and TNBS did not result in clear-cut Th2 and Th1/Th17 pathway signaling at this early timepoint, but the applied molecular tools may provide further insight to the IBD pathogenesis and translational value of the IBD zebrafish model.
