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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

Dynamics of T and B cell migration in head kidney after infection. Ordinate shows the relative number of mRNA copies (per μg total RNA) encoding the T cell receptor beta (TRB) and immunoglobulin M (Ighm) inhead kidney of five individuals/time point at various times after infection (abscissa). Values are given as mean ± SEM. Note that the relative quantity is presented on a log10 scale. Asterisks denote statistical significance with p < 0.01 (∗∗) and p < 0.05 (∗) compared to controls above (ighm) and below (trb) the graph. Statistical significance was assessed with a double sided t-test.
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fig6: Dynamics of T and B cell migration in head kidney after infection. Ordinate shows the relative number of mRNA copies (per μg total RNA) encoding the T cell receptor beta (TRB) and immunoglobulin M (Ighm) inhead kidney of five individuals/time point at various times after infection (abscissa). Values are given as mean ± SEM. Note that the relative quantity is presented on a log10 scale. Asterisks denote statistical significance with p < 0.01 (∗∗) and p < 0.05 (∗) compared to controls above (ighm) and below (trb) the graph. Statistical significance was assessed with a double sided t-test.

Mentions: We profiled the dynamics of lymphoid cell migration in the four immune organs in order to validate the onset of adaptive immune activities involving T and B cells. T cell receptor β (trb) and immunoglobulin M, heavy chain (ighm) are broadly used gene markers indicating the presence of cells of the T- or B-type lineage [39]. We found only in the head kidney clear and significant changes of these markers (p = 0.03). The trb level remained stable for 12 hpi and subsequently rose to reach its maximum 12-fold increase at 72 hpi. Concomitantly, the ighm level dropped steeply after 12 hpi and reached a lower level plateau (11-fold reduction) at 24 hpi (Figure 6). This observation indicates either that B cells emigrated from the head kidney or that T or myeloid cells immigrated into this organ or that lymphocytes were strongly induced to proliferate here, thereby affecting the proportion of immune cells.


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)

Dynamics of T and B cell migration in head kidney after infection. Ordinate shows the relative number of mRNA copies (per μg total RNA) encoding the T cell receptor beta (TRB) and immunoglobulin M (Ighm) inhead kidney of five individuals/time point at various times after infection (abscissa). Values are given as mean ± SEM. Note that the relative quantity is presented on a log10 scale. Asterisks denote statistical significance with p < 0.01 (∗∗) and p < 0.05 (∗) compared to controls above (ighm) and below (trb) the graph. Statistical significance was assessed with a double sided t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig6: Dynamics of T and B cell migration in head kidney after infection. Ordinate shows the relative number of mRNA copies (per μg total RNA) encoding the T cell receptor beta (TRB) and immunoglobulin M (Ighm) inhead kidney of five individuals/time point at various times after infection (abscissa). Values are given as mean ± SEM. Note that the relative quantity is presented on a log10 scale. Asterisks denote statistical significance with p < 0.01 (∗∗) and p < 0.05 (∗) compared to controls above (ighm) and below (trb) the graph. Statistical significance was assessed with a double sided t-test.
Mentions: We profiled the dynamics of lymphoid cell migration in the four immune organs in order to validate the onset of adaptive immune activities involving T and B cells. T cell receptor β (trb) and immunoglobulin M, heavy chain (ighm) are broadly used gene markers indicating the presence of cells of the T- or B-type lineage [39]. We found only in the head kidney clear and significant changes of these markers (p = 0.03). The trb level remained stable for 12 hpi and subsequently rose to reach its maximum 12-fold increase at 72 hpi. Concomitantly, the ighm level dropped steeply after 12 hpi and reached a lower level plateau (11-fold reduction) at 24 hpi (Figure 6). This observation indicates either that B cells emigrated from the head kidney or that T or myeloid cells immigrated into this organ or that lymphocytes were strongly induced to proliferate here, thereby affecting the proportion of immune cells.

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