ARS | Publication request: Comparative catfish macrophage function in families expressing high and low survivor phenotype following experimental challenge with Edwardsiella ictaluri

Submitted to: Aquaculture America Conference
Publication Type: Abstract Only
Publication Acceptance Date: November 17, 2010
Publication Date: March 2, 2011
Citation: Booth, N.J., Peterson, B.C. 2011. Comparative catfish macrophage function in families expressing high and low survivor phenotype following experimental challenge with Edwardsiella ictaluri. Aquaculture America Conference. P. 71:194.

Technical Abstract: Two channel catfish families were identified as displaying a high (>90%) or low (<10%) survival phenotype in repeated experimental challenge with Edwardsiella ictaluri. In order to gain understanding of the biological basis of these phenotypes, primary macrophages were prepared from head kidney tissue from fish belonging to each family and cell function was analyzed by performing a Gentamicin exclusion assay to determine the ability of these cells to take up and kill E. ictaluri in vitro. There was no significant difference in initial uptake of bacteria in cells of either family. Surprisingly, replication rates of bacteria were significantly higher in macrophages derived from the high survivors than in those from low survivors. Results indicate that high survivor catfish macrophages were not able to control intracellular growth and replication of E. ictaluri as efficiently as low survivor macrophages. This data, together with data collected from innate immunity-associated gene expression studies in fish from families expressing these two disparate phenotypes may provide insight into how E. ictaluri causes infection in catfish with different susceptibility phenotypes.