TY - JOUR

T1 - Epidermal response of rainbow trout to Ichthyobodo necator

T2 - immunohistochemical and gene expression studies indicate a Th1-/Th2-like switch

AU - Chettri, Jiwan Kumar

AU - Kuhn, Jesper Andreas

AU - Mohammad, Rezkar Jaafar

AU - Kania, Per Walter

AU - Møller, Ole Sten

AU - Buchmann, Kurt

N1 - © 2013 John Wiley & Sons Ltd.

PY - 2014

Y1 - 2014

N2 - Infections with the parasitic flagellate Ichthyobodo necator (Henneguy, 1883) cause severe skin and gill disease in rainbow trout Oncorhynchus mykiss (Walbaum, 1792) juveniles. The epidermal disturbances including hyperplasia and mucous cell exhaustion caused by parasitization are known, but no details on specific cellular and humoral reactions have been presented. By applying gene expression methods and immunohistochemical techniques, further details of immune processes in the affected skin can be presented. A population of I. necator was established in the laboratory and used to induce an experimental infection of juvenile rainbow trout. The course of infection was followed by sampling for parasite enumeration, immunohistochemistry (IHC) and quantitative PCR (qPCR) on days 0, 5, 9 and 14 post-infection. IHC showed a significant increase in the occurrence of IgM-positive cells in the skin of the infected fish, whereas IgT-positive cells were eliminated and the number of CD8-positive cells declined. qPCR studies supported the IHC findings showing a significant increase in IgM and a decrease in the CD8 gene expression. In addition, genes encoding innate immune genes such as lysozyme, SAA and cathelicidin 2 were up-regulated. Expression of cytokines (IL-1β, IL-4/13A, IL-6, IL-8, IL-10), the cell marker CD4 and the transcription factor GATA3 showed a significant increase after infection. Cytokine profiling including up-regulation of IL-4/13A and IL-10 genes and transcription factor GATA3 connected to the proliferation of IgM producing lymphocytes suggests a partial shift towards a Th2 response associated with the I. necator infection.

AB - Infections with the parasitic flagellate Ichthyobodo necator (Henneguy, 1883) cause severe skin and gill disease in rainbow trout Oncorhynchus mykiss (Walbaum, 1792) juveniles. The epidermal disturbances including hyperplasia and mucous cell exhaustion caused by parasitization are known, but no details on specific cellular and humoral reactions have been presented. By applying gene expression methods and immunohistochemical techniques, further details of immune processes in the affected skin can be presented. A population of I. necator was established in the laboratory and used to induce an experimental infection of juvenile rainbow trout. The course of infection was followed by sampling for parasite enumeration, immunohistochemistry (IHC) and quantitative PCR (qPCR) on days 0, 5, 9 and 14 post-infection. IHC showed a significant increase in the occurrence of IgM-positive cells in the skin of the infected fish, whereas IgT-positive cells were eliminated and the number of CD8-positive cells declined. qPCR studies supported the IHC findings showing a significant increase in IgM and a decrease in the CD8 gene expression. In addition, genes encoding innate immune genes such as lysozyme, SAA and cathelicidin 2 were up-regulated. Expression of cytokines (IL-1β, IL-4/13A, IL-6, IL-8, IL-10), the cell marker CD4 and the transcription factor GATA3 showed a significant increase after infection. Cytokine profiling including up-regulation of IL-4/13A and IL-10 genes and transcription factor GATA3 connected to the proliferation of IgM producing lymphocytes suggests a partial shift towards a Th2 response associated with the I. necator infection.

U2 - 10.1111/jfd.12169

DO - 10.1111/jfd.12169

M3 - Journal article

C2 - 23952070

VL - 37

SP - 771

EP - 783

JO - Journal of Fish Diseases Online

JF - Journal of Fish Diseases Online

SN - 1365-2761

IS - 9

ER -