Edwardsiella ictaluri invasion of IEC-6, Henle 407, fathead minnow and channel catfish enteric epithelial cells

Diseases of Aquatic Organisms

Ramona T. Skirpstunas¹  Thomas J. Baldwin¹ 

关键词: Edwardsiella ictaluri;    Enteric septicemia of catfish;    ESC;    Catfish diseases;   

DOI  :  10.3354/dao051161

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Invasion of Edwardsiella ictaluri into cultured mammalian, fish and enzymatically harvested catfish enteric epithelial cells is described. Gentamicin survival assays were used to demonstrate the ability of this catfish pathogen to invadeIEC-6 (origin: rat small intestinal epithelium), Henle 407 (origin: human embryonic intestinal epithelium), fathead minnow (FHM, minnow epithelial cells) and trypsin/pepsin-harvested channel catfish enteric epithelial cells. Invasion of all cell typesoccurred within 2 h of contact at 26°C, in contrast to Escherichia coli DH5 α, which did not invade cells tested. Eight Edwardsiella ictaluri isolates from diseased catfish and the ATCC (American Type CultureCollection) strain were evaluated for invasion efficiency using FHM cells. All isolates were invasive, but at differing efficiencies. Invasion blocking assays using chemical blocking agents were performed on a single isolate (LA 89-9) using IEC-6epithelial cells. Preincubation of IEC-6 cells with cytochalasin D (microfilament depolymerizer) and monodansylcadaverine (blocks receptor-mediated endocytosis) significantly reduced invasion by E. ictaluri, whereas exposure to colchicine(microtubule depolymerizer) had no effect on bacterial internalization. Results indicate that actin polymerization and receptor-mediated endocytosis are involved in uptake of E. ictaluri by IEC-6 epithelial cells. Invasion trials using freshlyharvested cells from the intestine of the natural host, Ictalurus punctatus, show that invasion occurs, but at a low efficiency. This is possibly due to loss of outer membrane receptors during enzymatic cell harvest. This study provides the firstdocumentation of the invasion of cultured mammalian and fish cells by E. ictaluri, and identifies possible mechanisms used for intracellular access. Additionally, the study describes several functional in vitro invasion models usingcommercially available cell lines as well as cells from the natural host (channel catfish, I. punctatus).

【 授权许可】

Unknown