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Query: UNIPROT:P05231 (
interleukin-6
)
23,907
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Highly pathogenic avian H5N1 influenza viruses are now widespread in poultry in Asia and have recently spread to some African and European countries. Interspecies transmission of these viruses to humans poses a major threat to public health. To better understand the basis of pathogenesis of H5N1 viruses, we have investigated the role of proinflammatory cytokines in transgenic mice deficient in
interleukin-6
(
IL-6
), macrophage inflammatory protein 1 alpha (MIP-1alpha), IL-1 receptor (IL-1R), or tumor necrosis factor receptor 1 (TNFR1) by the use of two avian influenza A viruses isolated from humans, A/Hong Kong/483/97 (HK/483) and A/Hong Kong/486/97 (HK/486), which exhibit high and low lethality in mice, respectively. The course of disease and the extent of virus replication and spread in
IL-6
- and MIP-1alpha-deficient mice were not different from those observed in wild-type mice during acute infection with 1,000 50% mouse infective doses of either H5N1 virus. However, with HK/486 virus, IL-1R-deficient mice exhibited heightened morbidity and mortality due to infection, whereas no such differences were observed with the more virulent HK/483 virus. Furthermore, TNFR1-deficient mice exhibited significantly reduced morbidity following challenge with either H5N1 virus but no difference in viral replication and spread or ultimate disease outcome compared with wild-type mice. These results suggest that TNF-alpha may contribute to morbidity during H5N1 influenza
virus infection
, while IL-1 may be important for effective virus clearance in nonlethal H5N1 disease.
...
PMID:Role of host cytokine responses in the pathogenesis of avian H5N1 influenza viruses in mice. 1718 84
The apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G (APOBEC3G), a member of the APOBEC family possessing DNA mutator activity through cytosine deamination, is reported to play an important role in host defense against infections such as those of hepatitis B virus and human immunodeficiency virus. Here, we examined the expression of APOBEC3G in human kidney cells to better understand its biological role against infection. APOBEC3G was immunohistochemically detectable in kidney mesangial cells and also to some extent in kidney epithelial tubular cells. In addition, overexpression of APOBEC3G was shown in renal carcinoma tissues and cell lines. APOBEC3G expression was upregulated by inflammatory cytokines, such as interferon,
interleukin-6
, and tumor necrosis factor. These results may provide new insight into the role of APOBEC3G in host defense against
viral infection
and cancer.
...
PMID:Expression of APOBEC3G in kidney cells. 1721 12
Antibodies generated to the purified dengue type 2 virus (D-2V) nonstructural-1 (NS1) protein in mice and rabbits were compared with those generated to this protein in congeneic (H-2 class II) mouse strains and humans after D-2V infections. Unlike the profiles observed with the rabbits, similar antibody reaction profiles were generated by mice and humans with severe D-2V disease (dengue hemorrhagic fever [DHF]/dengue shock syndrome [DSS]). Many of these epitopes contained the core acidic-hydrophobic-basic (tri-amino-acid; ELK-type) motifs present in the positive or negative orientations. Antibody responses generated to these ELK/KLE-type motifs and the epitope LX1 on this protein were influenced by class II molecules in mice during D-2V infections; but these antibodies cross-reacted with human fibrinogen and platelets, as implicated in DHF/DSS pathogenesis. The core LX1 epitope (113YSWKTWG119), identified by the dengue virus complex-specific monoclonal antibody (MAb) 3D1.4, was prepared so that it contained natural I-Ad-binding and ELK-type motifs. This AFLX1 peptide, which appropriately displayed the ELK-type and LX1 epitopes in solid-phase immunoassays, generated a similar, but lower, immunodominant anti-ELK-motif antibody reaction in I-Ad-positive mice, as generated in mice and humans during D-2V infections. These antibody responses were much stronger in the high-responding mouse strains and each of the DHF/DSS patients tested and may therefore account for the association of DHF/DSS resistance or susceptibility with particular class II molecules and autoantibodies, antibody-stimulating cytokines (e.g.,
interleukin-6
), and complement product C3a being implicated in DHF/DSS pathogenesis. These results are likely to be important for the design of a safe vaccine against this
viral disease
and showed the AFLX1 peptide and MAb 3D1.4 to be valuable diagnostic reagents.
...
PMID:Antibody responses are generated to immunodominant ELK/KLE-type motifs on the nonstructural-1 glycoprotein during live dengue virus infections in mice and humans: implications for diagnosis, pathogenesis, and vaccine design. 1732 45
Prior exposure to social disruption stress (SDR) exacerbates both the acute and chronic phase of Theiler's murine encephalomyelitis
virus infection
(TMEV; [Johnson, R.R., Storts, R., Welsh, T.H., Jr., Welsh, C.J., Meagher, M.W., 2004. Social stress alters the severity of acute Theiler's
virus infection
. J. Neuroimmunol. 148, 74--85; Johnson, R.R., Prentice, T.W., Bridegam, P., Young, C.R., Steelman, A.J., Welsh, T.H., Welsh, C.J.R., Meagher, M.W., 2006. Social stress alters the severity and onset of the chronic phase of Theiler's
virus infection
. J. Neuroimmunol. 175, 39--51]). However, the neuroimmune mechanism(s) mediating this effect have not been determined. The present study examined whether stress-induced increases in the proinflammatory cytokine
interleukin-6
(
IL-6
) contributes to the adverse effects of SDR on acute TMEV infection. Experiment 1 demonstrated that SDR increases central and peripheral levels of
IL-6
and that this effect is reversed by intracerebral ventricular infusion of neutralizing antibody to
IL-6
prior to each of six SDR sessions. Although SDR reduced the sensitivity of spleen cells to the anti-inflammatory effects of corticosterone, the neutralizing antibody to
IL-6
did not alter this effect. To investigate whether stress-induced increases in
IL-6
contribute to the exacerbation of acute TMEV infection, Experiment 2 examined whether intracerebral administration of neutralizing antibody to
IL-6
during SDR would prevent the subsequent exacerbation of acute TMEV infection. Experiment 3 then replaced the social stress with intracerebral infusion of
IL-6
to assess sufficiency. As expected, prior exposure to SDR subsequently increased infection-related sickness behaviors, motor impairment, CNS viral titers, and CNS inflammation. These deleterious effects of SDR were either prevented or significantly attenuated by intracerebral infusion of neutralizing antibody to
IL-6
during the stress exposure period. However, infusion of
IL-6
alone did not mimic the adverse effects of SDR. We conclude that
IL-6
is necessary but not sufficient to exacerbate acute TMEV infection.
...
PMID:Interleukin-6 as a mechanism for the adverse effects of social stress on acute Theiler's virus infection. 1759 34
Primary differentiated respiratory epithelial cell cultures closely model the in vivo environment and allow for studies of innate immune responses generated specifically by epithelial cells, the primary cell type infected by human influenza A virus strains. We used primary murine tracheal epithelial cell (mTEC) cultures to investigate antiviral and cytokine responses to influenza A
virus infection
, focusing on the contribution of the RNA binding domain of the NS1 protein. rWSN NS1 R38A replication is attenuated in mTEC cultures; however, viral antigen is detected predominantly in ciliated cells, similar to wild-type virus. NS1 and NS1 R38A proteins display a primarily cytoplasmic localization in infected mTEC cultures. Increased production of tumor necrosis factor alpha,
interleukin-6
, and beta interferon is observed during rWSN NS1 R38A infection, and cytokines are secreted in a directional manner. Cytokine pretreatment of mTEC cultures and Vero cells suggest that rWSN NS1 R38A is more sensitive to the presence of antiviral/inflammatory cytokines than wild-type virus. Our results demonstrate that the RNA binding domain is a critical regulator of both cytokine production and cytokine sensitivity during influenza A
virus infection
of primary tracheal epithelial cells.
...
PMID:The RNA binding domain of influenza A virus NS1 protein affects secretion of tumor necrosis factor alpha, interleukin-6, and interferon in primary murine tracheal epithelial cells. 1759 5
The V protein of parainfluenza virus 5 (PIV5) plays an important role in the evasion of host immune responses. The V protein blocks interferon (IFN) signaling in human cells by causing degradation of the STAT1 protein, a key component of IFN signaling, and blocks IFN-beta production by preventing nuclear translocation of IRF3, a key transcription factor for activating IFN-beta promoter.
Interleukin-6
(
IL-6
), along with tumor necrosis factor (TNF)-alpha and IL-1beta, is a major proinflammatory cytokine that plays important roles in clearing
virus infection
through inflammatory responses. Many viruses have developed strategies to block
IL-6
expression. Wild-type PIV5 infection induces little, if any, expression of cytokines such as
IL-6
or TNF-alpha, whereas infection by a mutant PIV5 lacking the conserved C-terminal cysteine rich domain (rPIV5VDeltaC) induced high levels of
IL-6
expression. Examination of mRNA levels of
IL-6
indicated that the transcription activation of
IL-6
played an important role in the increased
IL-6
expression. Co-infection with wild-type PIV5 prevented the activation of
IL-6
transcription by rPIV5VDeltaC, and a plasmid encoding the full-length PIV5 V protein prevented the activation of
IL-6
promoter-driven reporter gene expression by rPIV5VDeltaC, indicating that the V protein played a role in inhibiting
IL-6
transcription. The activation of
IL-6
was independent of IFN-beta even though rPIV5VDeltaC-infected cells produced IFN-beta. Using reporter gene assays and chromatin immunoprecipitation (ChIP), it was found that NF-kappaB played an important role in activating expression of
IL-6
. We have proposed a model of activating and inhibiting
IL-6
transcription by PIV5.
...
PMID:Inhibition of interleukin-6 expression by the V protein of parainfluenza virus 5. 1769 82
Circulating myeloid cells such as plasmacytoid dendritic cells (pDC), blood DC and monocytes act as blood sentinels detecting invading pathogens through a large repertoire of expression of toll-like receptors (TLRs). Activation of these receptors is crucial to detect invading pathogens by the innate immune system. In the present work, we analysed the TLR responsiveness of fibrocytes, a blood-derived cell type of myeloid origin. Fibrocytes efficiently responded to TLR2, TLR4, and TLR7 ligands as well as to poly (I:C) or viral stimulation by producing high amount of
interleukin-6
. Upon
virus infection
of fibrocytes, IFN type I was also induced. When compared to pDC or Flt3 ligand-derived DC, fibrocytes produced 5 times and 60 times more IL-6, respectively. This response was associated with a rapid and efficient translocation of the NF-kappaB transcription factor. Analysis of the expression and functionality of TLR7 in peripheral blood leukocyte subpopulations suggested that this receptor is expressed and functional in a CD163(+) monocytic cell subpopulation containing the fibrocyte precursors. Considering the rapid entry of fibrocytes into wounds, this efficient responsiveness to TLR danger signals, reflects a potentially important role of these cells in the first line of defence against pathogen invasion following traumata.
...
PMID:Responsiveness of fibrocytes to toll-like receptor danger signals. 1808 71
To analyze human herpesvirus 6 (HHV-6) infection in adult living related liver transplantation, we performed a virological analysis, including viral isolation, serological assay, and real-time polymerase chain reaction, of serially collected blood samples from 67 recipients. In addition, cytokine levels were measured to determine their role in viral reactivation. HHV-6 was isolated from only 4 recipients (6.0%), and viral DNA was detected in 15 (22.4%) of the 67 recipients. A significant increase in HHV-6 immunoglobulin G antibody titers was observed in 19 (28.4%) of the 67 recipients. Finally, 26 recipients (38.8%) had HHV-6 reactivation 2-6 weeks after transplantation. HHV-6 associated clinical features were analyzed in the 17 recipients presenting with either viremia or DNAemia. Two recipients with viremia and 3 recipients with DNAemia had unexplained fever at the time of
viral infection
. An increase in aminotransferase levels was observed in 2 recipients with viremia and 3 recipients with DNAemia. Recipients with liver cirrhosis caused by hepatitis B virus or hepatitis C
virus infection
as the underlying disease were more likely to have HHV-6 infection (P = 0.025). Mortality at the last follow-up in recipients with HHV-6 reactivation was significantly higher than in those without viral reactivation (P = 0.0118). Plasma
interleukin-6
levels were significantly higher in the recipients with HHV-6 viremia than in the recipients without viremia at 4 weeks post-transplant (P = 0.0411). Moreover, tumor necrosis factor alpha levels were also higher in recipients with HHV-6 viremia (P < 0.0001) or reactivation (P = 0.0011) than in recipients without viremia or reactivation 4 weeks post-transplant.
...
PMID:Human herpesvirus 6 infection in adult living related liver transplant recipients. 1816 70
Alphaviruses such as Ross River virus (RRV) and chikungunya virus are mosquito-transmitted viruses that cause explosive epidemics of debilitating arthritis and myositis affecting millions of humans worldwide. Previous studies using a mouse model of RRV-induced disease demonstrated that
viral infection
results in a severe inflammatory arthritis and myositis and that complement component 3 (C3) contributes to the destructive phase of the inflammatory disease but not the recruitment of cellular infiltrates to the sites of RRV-induced inflammation. Here, we demonstrate that mice deficient in complement receptor 3 (CR3) (CD11b(-/-)), a signaling receptor activated by multiple ligands including the C3 cleavage fragment iC3b, develop less-severe disease signs and decreased tissue destruction compared to RRV-infected wild-type mice. CR3 deficiency had no effect on viral replication, nor did it diminish the magnitude, kinetics, and composition of the cellular infiltrates at the sites of inflammation. However, the genetic absence of CR3 diminished the expression of specific proinflammatory and cytotoxic effectors, including S100A9/S100A8 and
interleukin-6
, within the inflamed tissues, suggesting that CR3-dependent signaling at the sites of inflammation contributes to tissue damage and severe disease.
...
PMID:Complement receptor 3 promotes severe ross river virus-induced disease. 1878 4
Viral infection
of the liver can lead to severe tissue damage when high levels of viral replication and spread in the organ are coupled with strong induction of inflammatory responses. Here we report an unexpected correlation between the expression of a functional X domain encoded by the hepatotropic mouse hepatitis virus strain A59 (MHV-A59), the high-level production of inflammatory cytokines, and the induction of acute viral hepatitis in mice. X-domain (also called macro domain) proteins possess poly-ADP-ribose binding and/or ADP-ribose-1''-phosphatase (ADRP) activity. They are conserved in coronaviruses and in members of the "alpha-like supergroup" of phylogenetically related positive-strand RNA viruses that includes viruses of medical importance, such as rubella virus and hepatitis E virus. By using reverse genetics, we constructed a recombinant murine coronavirus MHV-A59 mutant encoding a single-amino-acid substitution of a strictly conserved residue that is essential for coronaviral ADRP activity. We found that the mutant virus replicated to slightly reduced titers in livers but, strikingly, did not induce liver disease. In vitro, the mutant virus induced only low levels of the inflammatory cytokines tumor necrosis factor alpha and
interleukin-6
(
IL-6
). In vivo, we found that
IL-6
production, in particular, was reduced in the spleens and livers of mutant virus-infected mice. Collectively, our data demonstrate that the MHV X domain exacerbates MHV-induced liver pathology, most likely through the induction of excessive inflammatory cytokine expression.
...
PMID:Mouse hepatitis virus liver pathology is dependent on ADP-ribose-1''-phosphatase, a viral function conserved in the alpha-like supergroup. 1892 71
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