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Title: Analysis of a Catfish Gene Resembling Interleukin-8: CDNA Cloning, Gene Structure, and Expression After Infection with Edwardsiella ictaluri

Author
item CHEN, L - AUBURN UNIVERSITY
item HE, C - AUBURN UNIVERSITY
item BAOPRASERTKUL, P - AUBURN UNIVERSITY
item XU, P - AUBURN UNIVERSITY
item LI, P - AUBURN UNIVERSITY
item SERAPION, J - AUBURN UNIVERSITY
item Waldbieser, Geoffrey - Geoff
item Wolters, William
item LIU, Z - AUBURN UNIVERSITY

Submitted to: Developmental and Comparative Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2004
Publication Date: 2/1/2005
Citation: Chen, L., He, C., Baoprasertkul, P., Xu, P., Li, P., Serapion, J., Waldbieser, G.C., Wolters, W.R., Liu, Z. 2005. Analysis of a Catfish Gene Resembling Interleukin-8: CDNA Cloning, Gene Structure, and Expression After Infection with Edwardsiella ictaluri. Developmental and Comparative Immunology 29:135-142.

Interpretive Summary: Chemokines are important molecules that recruit, activate, and localize white blood cells to regions of inflammation due to pathogens, but little is known about these molecules in catfish. Thus the catfish gene encoding the chemokine interleukin-8 (IL-8) was cloned and sequenced. Experiments demonstrated that when channel catfish and blue catfish were infected with the pathogenic bacteria Edwardsiella ictaluri, the IL-8 gene activity was 3 to 5 times higher than in non-infected fish. This research provided molecular tools useful for following IL-8 gene activity throughout infectious processes, and identifying variations in IL-8 gene expression that may influence resistance to diseases in catfish populations.

Technical Abstract: Chemokines are important mediators for innate immunity involved in recruitment, activation and adhesion of a variety of leukocyte types to inflammatory foci. While almost all chemokines have been identified from mammals, only a handful of fish chemokines have been identified. Here we report molecular cloning, sequence analysis, and expression of a channel catfish gene resembling interleukin-8 (IL-8). The gene has two alternatively spliced transcripts encoding 114 and 111 amino acids, respectively. The gene has four exons and three introns, typical of the CXC chemokine gene organization. In spite of the structural conservation through evolution, the piscine IL-8 genes showed a much greater sequence divergence than their counterparts among mammals. RT-PCR indicated that both spliced forms were expressed. Expression of the IL-8 like gene was up-regulated 3–5-fold in channel catfish and blue catfish after infection with pathogenic bacteria Edwardsiella ictaluri.