Differential immune response of rainbow trout (Oncorhynchus mykiss) at early developmental stages (larvae and fry) against the bacterial pathogen Yersinia ruckeri
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Differential immune response of rainbow trout (Oncorhynchus mykiss) at early developmental stages (larvae and fry) against the bacterial pathogen Yersinia ruckeri. / Chettri, Jiwan Kumar; Raida, Martin Kristian; Kania, Per Walter; Buchmann, Kurt.
In: Developmental & Comparative Immunology, Vol. 36, No. 2, 2012, p. 463-474.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Differential immune response of rainbow trout (Oncorhynchus mykiss) at early developmental stages (larvae and fry) against the bacterial pathogen Yersinia ruckeri
AU - Chettri, Jiwan Kumar
AU - Raida, Martin Kristian
AU - Kania, Per Walter
AU - Buchmann, Kurt
PY - 2012
Y1 - 2012
N2 - Innate immune factors play a crucial role in survival of young fish especially during early stages of life whenadaptive immunity is not fully developed. In the present study, we investigated the immune response ofrainbow trout (Oncorhynchus mykiss) larvae and fry at an early stage of development. We exposed 17and 87 days post hatch larvae and fry (152 and 1118 degree days post hatch; avg. wt. 70 and 770 mg,respectively) to the bacterial pathogen, Yersinia ruckeri for 4 h by bath challenge. Samples were taken at4, 24, 72 and 96 h post exposure for qPCR and immunohistochemical analyses to elucidate the immuneresponse mounted by these young fish. Larvae showed no mortality although infected larvae at 48 h postexposure showed hyperaemia in the mouth region and inflammation on the dorsal side of the body. Geneexpression studies showed an up-regulation of iNOS and IL-22 in infected larvae 24 h post exposure butmost of the investigated genes did not show any difference between infected and uninfected larvae. Immunohistochemicalstudies demonstrated a high expression of IgT molecules in gills and CD8 positive cells inthymus of both infected and uninfected larvae. Infection of rainbow trout fry with Y. ruckeri, in contrast,induced a cumulative mortality of 74%. A high expression of cytokines (IL-1b, TNF-a, IL-22, IL-8 and IL-10), acute phase proteins (SAA, hepcidin, transferrin and precerebellin), complement factors (C3, C5 andfactor B), antimicrobial peptide (cathelicidin-2) and iNOS was found in infected fry when compared tothe uninfected control. IgT molecules and mannose binding lectins in gills of both infected and uninfectedfry were detected by immunohistochemistry. The study indicated that early life stages (yolk-sac larvae),merely up-regulate a few genes and suggests a limited capacity of larvae to mount an immune responseby gene regulation at the transcriptional level. Based on the observed clearance of bacteria and lack of mortalityit could be speculated that larvae may be covered by protective shield of different immune factorsproviding protection against broad range of pathogens. However, the increased susceptibility of older frysuggests that Y. ruckeri may utilize some of the immune elements to enter the naive fish. The up-regulationof iNOS and IL-22 in the infected larvae implicates an important role of these molecules in immuneresponse at early developmental stages. A dense covering of surfaces of gill filaments by IgT antibody inthe young fish suggest a role of this antibody as innate immune factor at early developmental stages.
AB - Innate immune factors play a crucial role in survival of young fish especially during early stages of life whenadaptive immunity is not fully developed. In the present study, we investigated the immune response ofrainbow trout (Oncorhynchus mykiss) larvae and fry at an early stage of development. We exposed 17and 87 days post hatch larvae and fry (152 and 1118 degree days post hatch; avg. wt. 70 and 770 mg,respectively) to the bacterial pathogen, Yersinia ruckeri for 4 h by bath challenge. Samples were taken at4, 24, 72 and 96 h post exposure for qPCR and immunohistochemical analyses to elucidate the immuneresponse mounted by these young fish. Larvae showed no mortality although infected larvae at 48 h postexposure showed hyperaemia in the mouth region and inflammation on the dorsal side of the body. Geneexpression studies showed an up-regulation of iNOS and IL-22 in infected larvae 24 h post exposure butmost of the investigated genes did not show any difference between infected and uninfected larvae. Immunohistochemicalstudies demonstrated a high expression of IgT molecules in gills and CD8 positive cells inthymus of both infected and uninfected larvae. Infection of rainbow trout fry with Y. ruckeri, in contrast,induced a cumulative mortality of 74%. A high expression of cytokines (IL-1b, TNF-a, IL-22, IL-8 and IL-10), acute phase proteins (SAA, hepcidin, transferrin and precerebellin), complement factors (C3, C5 andfactor B), antimicrobial peptide (cathelicidin-2) and iNOS was found in infected fry when compared tothe uninfected control. IgT molecules and mannose binding lectins in gills of both infected and uninfectedfry were detected by immunohistochemistry. The study indicated that early life stages (yolk-sac larvae),merely up-regulate a few genes and suggests a limited capacity of larvae to mount an immune responseby gene regulation at the transcriptional level. Based on the observed clearance of bacteria and lack of mortalityit could be speculated that larvae may be covered by protective shield of different immune factorsproviding protection against broad range of pathogens. However, the increased susceptibility of older frysuggests that Y. ruckeri may utilize some of the immune elements to enter the naive fish. The up-regulationof iNOS and IL-22 in the infected larvae implicates an important role of these molecules in immuneresponse at early developmental stages. A dense covering of surfaces of gill filaments by IgT antibody inthe young fish suggest a role of this antibody as innate immune factor at early developmental stages.
KW - Former LIFE faculty
KW - Early life stages
KW - Larvae
KW - Innate immunity
KW - I&T
KW - CD8
KW - Cytokines
KW - Acute phase proteins
KW - IL-22
KW - iNOS
U2 - 10.1016/j.dci.2011.08.014
DO - 10.1016/j.dci.2011.08.014
M3 - Journal article
VL - 36
SP - 463
EP - 474
JO - Developmental and Comparative Immunology
JF - Developmental and Comparative Immunology
SN - 0145-305X
IS - 2
ER -
ID: 35243505