scholarly journals Orf virus-encoded interleukin-10 stimulates the proliferation of murine mast cells and inhibits cytokine synthesis in murine peritoneal macrophages

2002 ◽  
Vol 83 (5) ◽  
pp. 1049-1058 ◽  
Author(s):  
Wendy Imlach ◽  
Catherine A. McCaughan ◽  
Andrew A. Mercer ◽  
David Haig ◽  
Stephen B. Fleming
Keyword(s):  
Amino Acid ◽  
Mast Cells ◽  
Cell Types ◽  
Interleukin 10 ◽  
Peritoneal Macrophages ◽  
Orf Virus ◽  
Single Amino Acid ◽  
Viral Gene ◽  
Barr Virus ◽  
Polypeptide Structure

Orf virus (ORFV) is the type species of the parapoxvirus genus and produces cutaneous pustular lesions in sheep, goats and humans. The genome encodes a polypeptide with remarkable homology to interleukin-10 (IL-10), particularly ovine IL-10, and also to IL-10-like proteins encoded by Epstein–Barr virus (EBV) and equine herpesvirus. IL-10 is a pleiotropic cytokine that can exert either immunostimulatory or immunosuppressive effects on many cell types. We have expressed and purified C-terminal FLAG and His6-tagged versions of ORFV-IL-10 and shown that ORFV-IL-10 costimulates murine mast cells (MC/9) and inhibits tumour necrosis factor-α synthesis in activated mouse peritoneal macrophages. Our results demonstrate that although ORFV-IL-10 is structurally similar to EBV-IL-10 it has evolved a different spectrum of activities. EBV-IL-10 does not stimulate the proliferation of thymocytes or mast cells whereas ORFV-IL-10 has both of these activities. Recent studies show that the critical difference in molecular structure of human IL-10 and EBV-IL-10, which may be the basis of their functional differences, is linked to a single amino acid substitution. Consistent with the activity spectrum reported here for ORFV-IL-10, the viral gene encodes the critical amino acid seen in human IL-10. Although the ORFV-IL-10 gene has clearly undergone significant evolutionary change at the nucleotide level compared with ovine IL-10, it has largely retained the polypeptide structure and functional characteristics of its ovine counterpart, suggesting that mutations of the gene to a potentially more potent immunosuppressive form may compromise the co-existence of host and virus.

scholarly journals A Single Amino Acid Determines the Immunostimulatory Activity of Interleukin 10

2000 ◽  
Vol 191 (2) ◽  
pp. 213-224 ◽  
Author(s):  
Yaozhong Ding ◽  
Lihui Qin ◽  
Serguei V. Kotenko ◽  
Sidney Pestka ◽  
Jonathan S. Bromberg
Keyword(s):  
Amino Acid ◽  
Immune Responses ◽  
Cell Types ◽  
Interleukin 10 ◽  
Interferon Γ ◽  
Single Amino Acid ◽  
Immunostimulatory Activity ◽  
Barr Virus ◽  
Ligand Interactions ◽  
Epstein Barr

Cellular interleukin 10s (cIL-10s) of human and murine origin have extensive sequence and structural homology to the Epstein-Barr virus BCRF-I gene product, known as viral IL-10 (vIL-10). Although these cytokines share many immunosuppressive properties, vIL-10 lacks several of the immunostimulatory activities of cIL-10 on certain cell types. The molecular and cellular bases for this dichotomy are not currently defined. Here, we show that the single amino acid isoleucine at position 87 of cIL-10 is required for its immunostimulatory function. Substitution of isoleucine in cIL-10 with alanine, which corresponds to the vIL-10 residue, abrogates immunostimulatory activity for thymocytes, mast cells, and alloantigenic responses while preserving immunosuppressive activity for inhibition of interferon γ production and prolongation of cardiac allograft survival. Conversely, substitution of alanine with isoleucine in vIL-10 converts it to a cIL-10–like molecule with immunostimulatory activity. This single conservative residue alteration significantly affects ligand affinity for receptor; however, affinity changes do not necessarily alter specific activities for biologic responses in a predictable fashion. These results suggest complex regulation of IL-10 receptor–ligand interactions and subsequent biological responses. These results demonstrate that vIL-10 may represent a captured and selectively mutated cIL-10 gene that benefits viral pathogenesis by leading to ineffective host immune responses. The ability to manipulate the activity of IL-10 in either a stimulatory or suppressive direction may be of practical value for regulating immune responses for disease therapy, and of theoretical value for determining what aspects of IL-10 activity are important for normal T cell responses.

scholarly journals A Single Amino Acid in EBNA-2 Determines Superior B Lymphoblastoid Cell Line Growth Maintenance by Epstein-Barr Virus Type 1 EBNA-2

2014 ◽  
Vol 88 (16) ◽  
pp. 8743-8753 ◽  
Author(s):  
S. Tzellos ◽  
P. B. Correia ◽  
C. E. Karstegl ◽  
L. Cancian ◽  
J. Cano-Flanagan ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cell Line ◽  
Virus Type ◽  
Epstein Barr Virus ◽  
Lymphoblastoid Cell Line ◽  
Single Amino Acid ◽  
Barr Virus ◽  
Epstein Barr

Mechanisms of TNF induction by heat-killed Staphylococcus aureus differ upon the origin of mononuclear phagocytes

2011 ◽  
Vol 300 (4) ◽  
pp. C850-C859 ◽  
Author(s):  
Ronan Kapetanovic ◽  
Marianna Parlato ◽  
Catherine Fitting ◽  
Valérie Quesniaux ◽  
Jean-Marc Cavaillon ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Alveolar Macrophages ◽  
Cell Types ◽  
Interleukin 10 ◽  
Peritoneal Macrophages ◽  
Mononuclear Phagocyte ◽  
Mononuclear Phagocytes ◽  
Membrane Receptors ◽  
Cell Physiology ◽  
Bacterial Uptake

Mononuclear phagocytes are among the first immune cells activated after pathogens invasion. Although they all derive from the same progenitor in the bone marrow, their characteristics differ on the compartment from which they are derived. In this work, we investigated the contribution of phagocytosis for tumor necrosis factor (TNF) production by murine mononuclear phagocytes (monocytes, peritoneal and alveolar macrophages) in response to heat-killed Staphylococcus aureus (HKSA). Mononuclear phagocytes behaved differently, depending on their compartment of residence. Indeed, when bacterial uptake or phagosome maturation was blocked, activation through membrane receptors was sufficient for a maximal production of TNF and interleukin-10 by peritoneal macrophages. In contrast, monocytes, and to a lesser extent alveolar macrophages, required phagocytosis for optimal cytokine production. While investigating the different actors of signalization, we found that p38 kinase and phosphatidylinositol 3-kinase were playing an important role in HKSA phagocytosis and TNF production. Furthermore, blocking the α5β1-integrin significantly decreased TNF production in response to HKSA in all three cell types. Finally, using mononuclear phagocytes from NOD2 knockout mice, we observed that TNF production in response to HKSA was dependent on NOD2 for monocytes and peritoneal macrophages. In conclusion, we demonstrate that the mechanisms of activation leading to TNF production in response to HKSA are specific for each mononuclear phagocyte population and involve different recognition processes and signaling pathways. The influence of the compartments on cell properties and behavior should be taken into account, to better understand cell physiology and host-pathogen interaction, and to define efficient strategies to fight infection.

scholarly journals A Single Amino Acid Residue Change in the P Protein of Parainfluenza Virus 5 Elevates Viral Gene Expression

2008 ◽  
Vol 82 (18) ◽  
pp. 9123-9133 ◽  
Author(s):  
Khalid A. Timani ◽  
Dengyun Sun ◽  
Minghao Sun ◽  
Celia Keim ◽  
Yuan Lin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Amino Acid ◽  
Amino Acid Residue ◽  
Viral Gene Expression ◽  
Viral Rna ◽  
Single Amino Acid ◽  
Viral Gene ◽  
Wild Type ◽  
V Protein ◽  
P Protein

ABSTRACT Parainfluenza virus 5 (PIV5) is a prototypical paramyxovirus. The V/P gene of PIV5 encodes two mRNA species through a process of pseudotemplated insertion of two G residues at a specific site during transcription, resulting in two viral proteins, V and P, whose N termini of 164 amino acid residues are identical. Previously it was reported that mutating six amino acid residues within this identical region results in a recombinant PIV5 (rPIV5-CPI−) that exhibits elevated viral protein expression and induces production of cytokines, such as beta interferon and interleukin 6. Because the six mutations correspond to the shared region of the V protein and the P protein, it is not clear whether the phenotypes associated with rPIV5-CPI− are due to mutations in the P protein and/or mutations in the V protein. To address this question, we used a minigenome system and recombinant viruses to study the effects of mutations on the functions of the P and V proteins. We found that the P protein with six amino acid residue changes (Pcpi−) was more efficient than wild-type P in facilitating replication of viral RNA, while the V protein with six amino acid residue changes (Vcpi−) still inhibits minigenome replication as does the wild-type V protein. These results indicate that elevated viral gene expression in rPIV5-CPI− virus-infected cells can be attributed to a P protein with an increased ability to facilitate viral RNA synthesis. Furthermore, we found that a single amino acid residue change at position 157 of the P protein from Ser (the residue in the wild-type P protein) to Phe (the residue in Pcpi−) is sufficient for elevated viral gene expression. Using mass spectrometry and 33P labeling, we found that residue S157 of the P protein is phosphorylated. Based on these results, we propose that phosphorylation of the P protein at residue 157 plays an important role in regulating viral RNA replication.

scholarly journals A Single Amino Acid Change in Viral Genome-Associated Protein of Potato Virus Y Correlates with Resistance Breaking in ‘Virgin A Mutant’ Tobacco

1999 ◽  
Vol 89 (2) ◽  
pp. 118-123 ◽  
Author(s):  
Chikara Masuta ◽  
Mitsuyo Nishimura ◽  
Hiroshi Morishita ◽  
Tatsuji Hataya
Keyword(s):  
Amino Acid ◽  
Potato Virus ◽  
Viral Genome ◽  
Potato Virus Y ◽  
Cell Movement ◽  
Amino Acid Sequences ◽  
Single Amino Acid ◽  
Viral Gene ◽  
Resistance Breaking ◽  
Single Amino Acid Change

Tobacco cultivar Virgin A Mutant (VAM) is reported to have the recessive potyvirus resistance gene va. Varied levels of resistance were observed in VAM plants inoculated with Japanese potato virus Y (PVY) isolates. VAM was highly resistant to most of the PVY isolates tested and tolerant to three necrotic strain isolates of PVY-T. Based on data obtained from tissue printing and press blotting, the resistance appeared to be mainly at the level of cell-to-cell movement. PVY replicated in VAM proto-plasts, but the replication was 30% lower than in susceptible tobacco, suggesting that impairment of replication also contributes to resistance. To identify the viral gene product or products involved in VAM resistance, we isolated spontaneous resistance-breaking mutants by passing vein-banding (O strain) isolates several times through VAM plants. By comparing the amino acid sequences of the mutants with their original isolates, we identified a single amino acid substitution in the viral genome-associated protein (VPg) domain that is correlated with VAM resistance breaking. Together, these results suggest that, in addition to its role in replication, VPg plays an important role in the cell-to-cell movement of PVY.

scholarly journals Orf virus interleukin-10 inhibits cytokine synthesis in activated human THP-1 monocytes, but only partially impairs their proliferation

2007 ◽  
Vol 88 (6) ◽  
pp. 1677-1682 ◽  
Author(s):  
Lyn Wise ◽  
Catherine McCaughan ◽  
Chee Keong Tan ◽  
Andrew A. Mercer ◽  
Stephen B. Fleming
Keyword(s):  
Amino Acid ◽  
Skin Lesions ◽  
Interleukin 10 ◽  
Amino Acid Identity ◽  
Orf Virus ◽  
Inhibitory Effects ◽  
Acid Identity ◽  
Critical Residues ◽  
Cytokine Synthesis ◽  
Activated Monocytes

The sheep parapoxvirus orf virus (ORFV) induces acute, pustular skin lesions in humans. ORFV encodes an orthologue of interleukin-10 (IL-10) that, whilst it closely resembles ovine IL-10 (91 % amino acid identity), shows only 75 % amino acid identity to human IL-10 (hIL-10). The anti-inflammatory potential of ORFV IL-10 in human ORFV infection was investigated by examining its immunosuppressive effects on THP-1 monocytes. ORFV IL-10 and hIL-10 were shown to have equivalent inhibitory effects on the synthesis of proinflammatory cytokines in lipopolysaccharide-activated monocytes, but differed in their abilities to inhibit monocyte proliferation. Structural modelling of ORFV IL-10 revealed differences from hIL-10 in residues predicted to interact with IL-10 co-receptor 2 (IL-10R2), whereas there were very few differences in the residues predicted to interact with IL-10R1. These findings suggest that the partial ability of ORFV IL-10 to inhibit THP-1 monocyte proliferation may be due to the absence of critical residues that mediate the interaction with human IL-10R2.

scholarly journals Mutation of a Single Amino Acid Residue in the Basic Region of the Epstein-Barr Virus (EBV) Lytic Cycle Switch Protein Zta (BZLF1) Prevents Reactivation of EBV from Latency

2005 ◽  
Vol 79 (21) ◽  
pp. 13822-13828 ◽  
Author(s):  
Celine Schelcher ◽  
Sarah Valencia ◽  
Henri-Jacques Delecluse ◽  
Matthew Hicks ◽  
Alison J. Sinclair
Keyword(s):  
Amino Acid ◽  
Epstein Barr Virus ◽  
Cysteine Residue ◽  
Lytic Cycle ◽  
Single Amino Acid ◽  
Barr Virus ◽  
Single Amino Acid Residue ◽  
Independent Functions ◽  
Epstein Barr ◽  
Basic Region

ABSTRACT Zta, the product of the BZLF1 gene carried by Epstein-Barr virus (EBV), is crucial for reactivation of EBV from latency. Zta is a member of the bZIP family of transcription factors, and in common with many of these, Zta possesses a conserved cysteine residue in its basic region (C189) and a further cysteine residue in its ZIP region (C222). We demonstrate that C189 is required to reactivate EBV from latency but C222 is not and that this single amino acid affects two independent functions of Zta, (i) binding to a Zta-responsive site and (ii) manipulating the cell cycle.

scholarly journals Viral interleukin 10 is critical for the induction of B cell growth transformation by Epstein-Barr virus.

1993 ◽  
Vol 178 (2) ◽  
pp. 439-447 ◽  
Author(s):  
I Miyazaki ◽  
R K Cheung ◽  
H M Dosch
Keyword(s):  
B Cell ◽  
Epstein Barr Virus ◽  
Cell Transformation ◽  
Interleukin 10 ◽  
Transformation Process ◽  
Viral Gene ◽  
Cdna Subtraction ◽  
Barr Virus ◽  
Epstein Barr ◽  
Transformed Cell Lines

We have used an efficient cDNA subtraction library procedure to identify newly induced genes in human B lymphocytes infected for 6 h with Epstein-Barr virus (EBV). Among the genes identified by automated sequencing of a random subset of clones from this library, one coded the EBV BCRF1 open reading frame, which specifies the viral interleukin 10 gene (vIL-10). This molecule is highly homologous to human (h)IL-10 and was previously thought to represent a "late" viral gene expressed only during the lytic phase of virus replication. Using gene amplification by reverse transcriptase polymerase chain reaction of B cell RNA obtained at varying times after infection, we detected vIL-10 expression within a few hours of EBV infection, followed, 20-30 h later by expression of hIL-10. Expression of both genes continued beyond the initial transformation phase (5-10 d) and was present in all transformed cell lines tested. When added at the time of viral infection, antisense (but not sense) oligonucleotides for vIL-10 mRNA (cytosolic half-life, approximately 6 h) prevented subsequent B cell transformation. The antisense effect was highly specific, leaving the expression levels of other transformation-related genes intact. Addition of exogenous (h)IL-10 rescued the transformation process in antisense-treated cells. Our observations establish vIL-10 as a new latency gene with a directly transformation-prerequisite function.

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