Limits...
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.

Show MeSH

Related in: MedlinePlus

Transcription levels of PRRs genes in liver in response to VHSV.Rainbow trout were infected with VHSV as described in the legend of Figure 4 and the liver sampled to determine the levels of expression of PRR genes by real-time PCR. Data are shown as the mean gene expression relative to the expression of endogenous control EF-1α ± SD. Expression levels significantly different to those observed in mock-infected fish are noted as * (p<0.05), ** (p<0.001).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4206492&req=5

pone-0111084-g004: Transcription levels of PRRs genes in liver in response to VHSV.Rainbow trout were infected with VHSV as described in the legend of Figure 4 and the liver sampled to determine the levels of expression of PRR genes by real-time PCR. Data are shown as the mean gene expression relative to the expression of endogenous control EF-1α ± SD. Expression levels significantly different to those observed in mock-infected fish are noted as * (p<0.05), ** (p<0.001).

Mentions: Initial virus recognition is mainly related with the PRR system, including TLRs and RIG I-like receptors [31], [32]. In our model, the TLR3 gene appears significantly induced from the first day post-viral injection (Fig. 4), and this induction is even more significant (p<0.0002) at days 2 and 5 post-infection. After 2 days, TLR7 is also significantly up-regulated, and this significance is maintained at 5 days. TLR22, a fish specific TLR that recognizes double stranded RNA on the cell surface [33], was also significantly induced in liver samples from infected fish after 5 days (Fig. 4). Transcription of genes related to the RIG I-like receptors system such as MDA5, LGP2a and LGP2b were also significantly triggered in samples from VHSV-challenged fish.


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 PRRs genes in liver in response to VHSV.Rainbow trout were infected with VHSV as described in the legend of Figure 4 and the liver sampled to determine the levels of expression of PRR genes by real-time PCR. Data are shown as the mean gene expression relative to the expression of endogenous control EF-1α ± SD. Expression levels significantly different to those observed in mock-infected fish are noted as * (p<0.05), ** (p<0.001).
© Copyright Policy
Related In: Results  -  Collection

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

pone-0111084-g004: Transcription levels of PRRs genes in liver in response to VHSV.Rainbow trout were infected with VHSV as described in the legend of Figure 4 and the liver sampled to determine the levels of expression of PRR genes by real-time PCR. Data are shown as the mean gene expression relative to the expression of endogenous control EF-1α ± SD. Expression levels significantly different to those observed in mock-infected fish are noted as * (p<0.05), ** (p<0.001).
Mentions: Initial virus recognition is mainly related with the PRR system, including TLRs and RIG I-like receptors [31], [32]. In our model, the TLR3 gene appears significantly induced from the first day post-viral injection (Fig. 4), and this induction is even more significant (p<0.0002) at days 2 and 5 post-infection. After 2 days, TLR7 is also significantly up-regulated, and this significance is maintained at 5 days. TLR22, a fish specific TLR that recognizes double stranded RNA on the cell surface [33], was also significantly induced in liver samples from infected fish after 5 days (Fig. 4). Transcription of genes related to the RIG I-like receptors system such as MDA5, LGP2a and LGP2b were also significantly triggered in samples from VHSV-challenged fish.

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