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Aeromonas salmonicida Infection Only Moderately Regulates Expression of Factors Contributing to Toll-Like Receptor Signaling but Massively Activates the Cellular and Humoral Branches of Innate Immunity in Rainbow Trout (Oncorhynchus mykiss).

Brietzke A, Korytář T, Jaros J, Köllner B, Goldammer T, Seyfert HM, Rebl A - J Immunol Res (2015)

Bottom Line: In contrast, only the fish-specific tlr22a2 and the downstream factor irak1 featured clearly increased transcript levels, while the mRNA concentrations of many other tlr genes decreased.In conclusion, no specific TLR can be singled out as a dominant receptor for A. salmonicida.The recruitment of cellular factors of innate immunity rather than induced expression of pathogen receptors is hence of key importance for mounting a first immune defense against invading A. salmonicida.

View Article: PubMed Central - PubMed

Affiliation: Leibniz Institute for Farm Animal Biology (FBN), Institute of Genome Biology, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.

ABSTRACT
Toll-like receptors (TLRs) are known to detect a defined spectrum of microbial structures. However, the knowledge about the specificity of teleost Tlr factors for distinct pathogens is limited so far. We measured baseline expression profiles of 18 tlr genes and associated signaling factors in four immune-relevant tissues of rainbow trout Oncorhynchus mykiss. Intraperitoneal injection of a lethal dose of Aeromonas salmonicida subsp. salmonicida induced highly increased levels of cytokine mRNAs during a 72-hour postinfection (hpi) period. In contrast, only the fish-specific tlr22a2 and the downstream factor irak1 featured clearly increased transcript levels, while the mRNA concentrations of many other tlr genes decreased. Flow cytometry quantified cell trafficking after infection indicating a dramatic influx of myeloid cells into the peritoneum and a belated low level immigration of lymphoid cells. T and B lymphocytes were differentiated with RT-qPCR revealing that B lymphocytes emigrated from and T lymphocytes immigrated into head kidney. In conclusion, no specific TLR can be singled out as a dominant receptor for A. salmonicida. The recruitment of cellular factors of innate immunity rather than induced expression of pathogen receptors is hence of key importance for mounting a first immune defense against invading A. salmonicida.

No MeSH data available.


Related in: MedlinePlus

Modulation of the mRNA concentration of factors contributing to TLR signaling during infection. Colored fields represent significantly (p < 0.05) altered fold changes (>2-fold) of the mRNA concentrations as measured in the respective organs at the various times after infection. The pertinent data are listed in Tables 3(a) and 3(b).
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fig4: Modulation of the mRNA concentration of factors contributing to TLR signaling during infection. Colored fields represent significantly (p < 0.05) altered fold changes (>2-fold) of the mRNA concentrations as measured in the respective organs at the various times after infection. The pertinent data are listed in Tables 3(a) and 3(b).

Mentions: A key aspect of our study was to profile the expression of all our candidate Tlr factors during A. salmonicida infection identifying prominently regulated members of this receptor family. The data are visualized in Figure 4 and listed in Table 3(a). Surprisingly, from the 13 tlr genes studied, only the expression of tlr22a2 was clearly and quickly induced in head kidney (6 hpi: 6-fold; 12 hpi: 4-fold over controls) and liver (12 and 48 hpi: 4-fold over controls) in the infected trout. The genes encoding Tlr9, -19, and -20 were induced in liver to a low extent (2- to 3-fold; p < 0.05). Transcript levels of tlr1 and tlr22a1 remained stable over time and those encoding Tlr2, -3, -5, -7, -8a1, -8a2, -9, -21, and Nod1 were even downregulated (<4-fold) in spleen or head kidney.


Aeromonas salmonicida Infection Only Moderately Regulates Expression of Factors Contributing to Toll-Like Receptor Signaling but Massively Activates the Cellular and Humoral Branches of Innate Immunity in Rainbow Trout (Oncorhynchus mykiss).

Brietzke A, Korytář T, Jaros J, Köllner B, Goldammer T, Seyfert HM, Rebl A - J Immunol Res (2015)

Modulation of the mRNA concentration of factors contributing to TLR signaling during infection. Colored fields represent significantly (p < 0.05) altered fold changes (>2-fold) of the mRNA concentrations as measured in the respective organs at the various times after infection. The pertinent data are listed in Tables 3(a) and 3(b).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4525466&req=5

fig4: Modulation of the mRNA concentration of factors contributing to TLR signaling during infection. Colored fields represent significantly (p < 0.05) altered fold changes (>2-fold) of the mRNA concentrations as measured in the respective organs at the various times after infection. The pertinent data are listed in Tables 3(a) and 3(b).
Mentions: A key aspect of our study was to profile the expression of all our candidate Tlr factors during A. salmonicida infection identifying prominently regulated members of this receptor family. The data are visualized in Figure 4 and listed in Table 3(a). Surprisingly, from the 13 tlr genes studied, only the expression of tlr22a2 was clearly and quickly induced in head kidney (6 hpi: 6-fold; 12 hpi: 4-fold over controls) and liver (12 and 48 hpi: 4-fold over controls) in the infected trout. The genes encoding Tlr9, -19, and -20 were induced in liver to a low extent (2- to 3-fold; p < 0.05). Transcript levels of tlr1 and tlr22a1 remained stable over time and those encoding Tlr2, -3, -5, -7, -8a1, -8a2, -9, -21, and Nod1 were even downregulated (<4-fold) in spleen or head kidney.

Bottom Line: In contrast, only the fish-specific tlr22a2 and the downstream factor irak1 featured clearly increased transcript levels, while the mRNA concentrations of many other tlr genes decreased.In conclusion, no specific TLR can be singled out as a dominant receptor for A. salmonicida.The recruitment of cellular factors of innate immunity rather than induced expression of pathogen receptors is hence of key importance for mounting a first immune defense against invading A. salmonicida.

View Article: PubMed Central - PubMed

Affiliation: Leibniz Institute for Farm Animal Biology (FBN), Institute of Genome Biology, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.

ABSTRACT
Toll-like receptors (TLRs) are known to detect a defined spectrum of microbial structures. However, the knowledge about the specificity of teleost Tlr factors for distinct pathogens is limited so far. We measured baseline expression profiles of 18 tlr genes and associated signaling factors in four immune-relevant tissues of rainbow trout Oncorhynchus mykiss. Intraperitoneal injection of a lethal dose of Aeromonas salmonicida subsp. salmonicida induced highly increased levels of cytokine mRNAs during a 72-hour postinfection (hpi) period. In contrast, only the fish-specific tlr22a2 and the downstream factor irak1 featured clearly increased transcript levels, while the mRNA concentrations of many other tlr genes decreased. Flow cytometry quantified cell trafficking after infection indicating a dramatic influx of myeloid cells into the peritoneum and a belated low level immigration of lymphoid cells. T and B lymphocytes were differentiated with RT-qPCR revealing that B lymphocytes emigrated from and T lymphocytes immigrated into head kidney. In conclusion, no specific TLR can be singled out as a dominant receptor for A. salmonicida. The recruitment of cellular factors of innate immunity rather than induced expression of pathogen receptors is hence of key importance for mounting a first immune defense against invading A. salmonicida.

No MeSH data available.


Related in: MedlinePlus