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Early immune responses in rainbow trout liver upon viral hemorrhagic septicemia virus (VHSV) infection.

Castro R, Abós B, Pignatelli J, von Gersdorff Jørgensen L, González Granja A, Buchmann K, Tafalla C - PLoS ONE (2014)

Bottom Line: Our results indicate that T lymphocytes play a key role in the initial response to VHSV in the liver, since CD3, CD8, CD4, perforin, Mx and interferon (IFN) transcription levels were up-regulated in response to VHSV.Consequently, flow cytometry analysis of CD8α+ cells in liver and spleen at day 5 post-infection revealed a decrease in the number of CD8α+ cells in the spleen and an increased population in the liver.No differences were found however in the percentages of B lymphocyte (IgM+ or IgD+) populations.

View Article: PubMed Central - PubMed

Affiliation: Centro de Investigación en Sanidad Animal (CISA-INIA), Valdeolmos (Madrid), Spain.

ABSTRACT
Among the essential metabolic functions of the liver, in mammals, a role as mediator of systemic and local innate immunity has also been reported. Although the presence of an important leukocyte population in mammalian liver is well documented, the characterization of leukocyte populations in the teleost liver has been only scarcely addressed. In the current work, we have confirmed the presence of IgM+, IgD+, IgT+, CD8α+, CD3+ cells, and cells expressing major histocompatibility complex (MHC-II) in rainbow trout (Oncorhynchus mykiss) liver by flow cytometry and/or immunohistochemistry analysis. Additionally, the effect of viral hemorrhagic septicemia virus (VHSV) on the liver immune response was assessed. First, we studied the effect of viral intraperitoneal injection on the transcription of a wide selection of immune genes at days 1, 2 and 5 post-infection. These included a group of leukocyte markers genes, pattern recognition receptors (PRRs), chemokines, chemokine receptor genes, and other genes involved in the early immune response and in acute phase reaction. Our results indicate that T lymphocytes play a key role in the initial response to VHSV in the liver, since CD3, CD8, CD4, perforin, Mx and interferon (IFN) transcription levels were up-regulated in response to VHSV. Consequently, flow cytometry analysis of CD8α+ cells in liver and spleen at day 5 post-infection revealed a decrease in the number of CD8α+ cells in the spleen and an increased population in the liver. No differences were found however in the percentages of B lymphocyte (IgM+ or IgD+) populations. In addition, a strong up-regulation in the transcription levels of several PRRs and chemokines was observed from the second day of infection, indicating an important role of these factors in the response of the liver to viral infections.

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Transcription levels of immune genes characteristic of different leukocyte subpopulations in liver in response to VHSV.Rainbow trout were ip. infected with VHSV (5×105 TCID50/ml) or mock-infected. At days 1, 3 and 5 post-infection six trout from each group were killed and the liver sampled to determine the levels of expression of a selection of immune genes by real-time PCR. Data are shown as the mean gene expression relative to the expression of endogenous control EF-1α ± SD. * Levels of expression significantly different to those observed in mock-infected fish (p<0.05).
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pone-0111084-g003: Transcription levels of immune genes characteristic of different leukocyte subpopulations in liver in response to VHSV.Rainbow trout were ip. infected with VHSV (5×105 TCID50/ml) or mock-infected. At days 1, 3 and 5 post-infection six trout from each group were killed and the liver sampled to determine the levels of expression of a selection of immune genes by real-time PCR. Data are shown as the mean gene expression relative to the expression of endogenous control EF-1α ± SD. * Levels of expression significantly different to those observed in mock-infected fish (p<0.05).

Mentions: Firstly, the transcription levels of B lymphocyte marker genes, including total membrane and secreted IgM heavy chain, secreted IgM, total IgT, membrane IgD and secreted IgD were analyzed by real time PCR. We could not detect an effect of viral challenge in the levels of mRNA transcription at neither of the time points studied. On the contrary, the anti-viral response in the liver seemed to be more directed to a T-dependent response, as we observed significant up-regulation of the transcription levels of several T lymphocyte markers including CD3, CD8α, CD4-1 and CD4-2 at day 5 post-challenge (Fig. 3). Other B lymphocyte markers such as Blimp1, Pax5, or markers related with antigen presentation cells like MHC-II or Lamp3 showed no significant regulation due to viral infection at the time periods studied.


Early immune responses in rainbow trout liver upon viral hemorrhagic septicemia virus (VHSV) infection.

Castro R, Abós B, Pignatelli J, von Gersdorff Jørgensen L, González Granja A, Buchmann K, Tafalla C - PLoS ONE (2014)

Transcription levels of immune genes characteristic of different leukocyte subpopulations in liver in response to VHSV.Rainbow trout were ip. infected with VHSV (5×105 TCID50/ml) or mock-infected. At days 1, 3 and 5 post-infection six trout from each group were killed and the liver sampled to determine the levels of expression of a selection of immune genes by real-time PCR. Data are shown as the mean gene expression relative to the expression of endogenous control EF-1α ± SD. * Levels of expression significantly different to those observed in mock-infected fish (p<0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4206492&req=5

pone-0111084-g003: Transcription levels of immune genes characteristic of different leukocyte subpopulations in liver in response to VHSV.Rainbow trout were ip. infected with VHSV (5×105 TCID50/ml) or mock-infected. At days 1, 3 and 5 post-infection six trout from each group were killed and the liver sampled to determine the levels of expression of a selection of immune genes by real-time PCR. Data are shown as the mean gene expression relative to the expression of endogenous control EF-1α ± SD. * Levels of expression significantly different to those observed in mock-infected fish (p<0.05).
Mentions: Firstly, the transcription levels of B lymphocyte marker genes, including total membrane and secreted IgM heavy chain, secreted IgM, total IgT, membrane IgD and secreted IgD were analyzed by real time PCR. We could not detect an effect of viral challenge in the levels of mRNA transcription at neither of the time points studied. On the contrary, the anti-viral response in the liver seemed to be more directed to a T-dependent response, as we observed significant up-regulation of the transcription levels of several T lymphocyte markers including CD3, CD8α, CD4-1 and CD4-2 at day 5 post-challenge (Fig. 3). Other B lymphocyte markers such as Blimp1, Pax5, or markers related with antigen presentation cells like MHC-II or Lamp3 showed no significant regulation due to viral infection at the time periods studied.

Bottom Line: Our results indicate that T lymphocytes play a key role in the initial response to VHSV in the liver, since CD3, CD8, CD4, perforin, Mx and interferon (IFN) transcription levels were up-regulated in response to VHSV.Consequently, flow cytometry analysis of CD8α+ cells in liver and spleen at day 5 post-infection revealed a decrease in the number of CD8α+ cells in the spleen and an increased population in the liver.No differences were found however in the percentages of B lymphocyte (IgM+ or IgD+) populations.

View Article: PubMed Central - PubMed

Affiliation: Centro de Investigación en Sanidad Animal (CISA-INIA), Valdeolmos (Madrid), Spain.

ABSTRACT
Among the essential metabolic functions of the liver, in mammals, a role as mediator of systemic and local innate immunity has also been reported. Although the presence of an important leukocyte population in mammalian liver is well documented, the characterization of leukocyte populations in the teleost liver has been only scarcely addressed. In the current work, we have confirmed the presence of IgM+, IgD+, IgT+, CD8α+, CD3+ cells, and cells expressing major histocompatibility complex (MHC-II) in rainbow trout (Oncorhynchus mykiss) liver by flow cytometry and/or immunohistochemistry analysis. Additionally, the effect of viral hemorrhagic septicemia virus (VHSV) on the liver immune response was assessed. First, we studied the effect of viral intraperitoneal injection on the transcription of a wide selection of immune genes at days 1, 2 and 5 post-infection. These included a group of leukocyte markers genes, pattern recognition receptors (PRRs), chemokines, chemokine receptor genes, and other genes involved in the early immune response and in acute phase reaction. Our results indicate that T lymphocytes play a key role in the initial response to VHSV in the liver, since CD3, CD8, CD4, perforin, Mx and interferon (IFN) transcription levels were up-regulated in response to VHSV. Consequently, flow cytometry analysis of CD8α+ cells in liver and spleen at day 5 post-infection revealed a decrease in the number of CD8α+ cells in the spleen and an increased population in the liver. No differences were found however in the percentages of B lymphocyte (IgM+ or IgD+) populations. In addition, a strong up-regulation in the transcription levels of several PRRs and chemokines was observed from the second day of infection, indicating an important role of these factors in the response of the liver to viral infections.

Show MeSH
Related in: MedlinePlus