Expression Analysis of Selected Immune‐Relevant Genes in Channel Catfish during Edwardsiella ictaluri Infection

Abstract

Channel catfish Ictalurus punctatus were intraperitoneally challenged with the bacterium Edwardsiella ictaluri (the causative agent of enteric septicemia of catfish), and the expression of genes presumed to function in the inducible innate defense was evaluated. End-binding protein 1 (EB1), beta1-integrin, natural-resistance-associated macrophage protein (Nramp), heat shock protein 70 (Hsp70), serum amyloid P (SAP), and transferrin gene expression profiles were determined using quantitative reverse-transcriptase-polymerase chain reaction on liver, anterior kidney, spleen, and gut. Fish were subsampled at 0, 24, 48, 72, and 96 h after bacterial or phosphate-buffered-saline injection. Posterior kidney sampling demonstrated increasing bacterial counts at 24-48 h postinjection (hpi), followed by a plateau to 96 hpi. The transferrin and SAP transcripts were liver specific. The other genes were expressed in all four tissues. In bacterially infected fish, expression of EB1 (anterior kidney, spleen, and liver), Hsp70 (anterior kidney and spleen), and Nramp (spleen and gut) significantly increased by 48 hpi. Transferrin was strongly up-regulated and SAP was downregulated by 72 hpi, indicating positive and negative acute-phase reactants, respectively. The data indicate a substantial response of innate immunity effector cells by 48 hpi, followed by suppression of bacterial growth and induction of the acute-phase response. This suggests that the 48-72-hpi time frame is critical in our model for evaluating the effectiveness of innate defenses.

Defensive response of European sea bass (Dicentrarchus labrax) against Listonella anguillarum or Photobacterium damselae subsp. piscicida experimental infection

“…Otherwise, molecular methods have early indicated the increase of HSP70 transcripts in fish submitted to bacterial challenge (Elibol-Flemming et al, 2009;Dang et al, 2010). Similarly, the present study showed the up-regulation of the HSP70 in the thymus of L. anguillarum-infected fish.…”

Short Communication Effect of heat stress on heat-shock protein (Hsp60) mRNA expression in rainbow trout Oncorhynchus mykiss

“…In this study, spleen and head kidney hsp60 expression was consistently lower than that in liver tissue during heat stress. Elibol-Flemming et al (2009) demonstrated that splenic hsp70 expression is significantly lower than in the liver during acute-phase cell-stress responses. This suggests that the spleen and head kidney might have adapted to some chronic stressors, or that there may be other regulatory mechanisms involved.…”

Transcriptional profiles of multiple genes in the anterior kidney of channel catfish vaccinated with an attenuated Aeromonas hydrophila

“…In addition, the transcriptional levels of five toll-like receptors (TLRs) have been reported to be upregulated by acute infection with E. ictaluri [38]. Furthermore, the expression levels of tumor necrosis factor a (TNFa) [39], interleukin (IL)-1b [39], IL-10 [39], chemokine CXCL10 [40], hepcidin [32,41], bactericidal permeability-increasing protein [42], liver-expressed antimicrobial peptide-2 [43], transferrin [44], and cathepsin D [45] in channel catfish have been reported to be upregulated by bacterial infections. In addition, three channel catfish NK-lysine genes have been reported to be expressed in the anterior kidney of uninfected fish [46].…”