Maturation and function of human dendritic cells are inhibited by orf virus-encoded interleukin-10

The cooperation between orf virus and Staphylococcus aureus leads to intractable lesions in skin infection

A large amount of evidence shows that different kinds of microorganisms can jointly cope with environmental pressures including cell hosts. For example, in many cases, it has been found that secondary or mixed infection of animals caused by ORFV (an epitheliophilic Parapoxvirus) and bacteria (such as Staphylococcus aureus or Streptococcus) shows a mutual aid mode that indirectly leads to the deterioration of the disease. However, the lack of research on the co-pathogenic mechanism, including how to hijack and destroy the cell host in the pathological microenvironment, has hindered the in-depth understanding of the pathogenic process and consequences of this complex infection and the development of clinical treatment methods. Here, we summarized the current strategies of trapping cell hosts together, based on the previously defined ORFV-Host (O-H) system. The opportunistic invasion of S. aureus destroyed the delicate dynamic balance of the O-H, thus aggravating tissue damage through bacterial products (mediated by Agr), even causing sepsis or inducing cytokine storms. In fact, the virus products from its adaptive regulatory system (VARS) weaken the immune attacks and block molecular pathways, so that S. aureus can settle there more smoothly, and the toxins can penetrate into local tissues more quickly. This paper focuses on the main challenges faced by cell hosts in dealing with mixed infection, which provides a starting point for us to deal with this disease in the future.

Parapoxvirus Interleukin-10 Homologues Vary in Their Receptor Binding, Anti-Inflammatory, and Stimulatory Activities

Homologues of interleukin (IL)-10, a pleiotropic immunomodulatory cytokine, have been identified in the Parapoxvirus genus. The first identified, Orf virus (ORFV) IL-10, greatly enhanced infection of its host, exhibiting immune modulatory effects equivalent to human IL-10. IL-10-like genes were then identified in Bovine papular stomatitis virus (BPSV), Pseudocowpox virus (PCPV), Red deerpox virus (RDPV) and Grey sealpox virus (GSPV). This study aimed to produce and characterise recombinant parapoxvirus IL-10s, then quantitatively compare their receptor binding and immunomodulatory activities. Recombinant IL-10s were expressed, purified, then characterised using bioinformatic, biochemical and enzymatic analyses. Anti-inflammatory effects were assessed in lipoteichoic acid-activated THP-1 monocytes, and stimulatory effects in MC/9 mast cells. IL-10 receptor (IL-10R)1 binding was detected in a competitive displacement assay. BPSV IL-10 inhibited production of monocyte chemoattractant protein (MCP)-1, IL-8 and IL-1β, induced mast cell proliferation, and bound IL-10R1 similarly to ORFV IL-10. PCPV IL-10 showed reduced MCP-1 inhibition, mast cell proliferation, and IL-10R1 binding. RDPV IL-10 displayed reduced inhibition of IL-8 and MCP-1 production. GSPV IL-10 showed limited inhibition of IL-1β production and stimulation of mast cell proliferation. These findings provide valuable insight into IL-10 receptor interactions, and suggest that the parapoxvirus IL-10s play similar pathogenic roles during infection of their hosts.

The OH system: A panorama view of the PPV-host interaction

Poxviruses are a family of specialized cytoplasm-parasitic DNA viruses that replicate and assembly in virus factory. In Parapoxvirus (PPV) genus, with the orf virus (ORFV) as a representative species of this genus, their behaviors are significantly different from that of Orthopoxvirus, and the plots of viral practical solutions for evading host immunity are intricate and fascinating, particularly to anti-host and host's antiviral mechanisms. In order to protect the virus factory from immune elimination caused by infection, PPVs attempt to interfere with multiple stress levels of host, mainly by modulating innate immunity response (IIR) and adaptive immunity response (AIR). Given that temporarily constructed by virus infection, ORFV-HOST (OH) system accompanied by viral strategies is carefully managed in the virus factory, thus directing many life-critical events once undergoing the IIR and AIR. Evolutionarily, to reduce the risk of system destruction, ORFV have evolved into a mild-looking mode to avoid overstimulation. Moreover, the current version of development also focus on recognizing and hijacking more than eight antiviral security mechanisms of host cells, such as the 2',5'-oligoadenylate synthetase (OAS)/RNase L and PKR systems, the ubiquitin protease system (UPS), and so on. In summary, this review assessed inescapable pathways as mentioned above, through which viruses compete with their hosts strategically. The OH system provides a panoramic view and a powerful platform for us to study the PPV-Host interaction, as well as the corresponding implications on a great application potential in anti-virus design.

Cytomegalovirus mediates expansion of IL-15-responsive innate-memory cells with SIV killing function

Interindividual immune variability is driven predominantly by environmental factors, including exposure to chronic infectious agents such as cytomegalovirus (CMV). We investigated the effects of rhesus CMV (RhCMV) on composition and function of the immune system in young macaques. Within months of infection, RhCMV was associated with impressive changes in antigen presenting cells, T cells, and NK cells-and marked expansion of innate-memory CD8+ T cells. These cells express high levels of NKG2A/C and the IL-2 and IL-15 receptor beta chain, CD122. IL-15 was sufficient to drive differentiation of the cells in vitro and in vivo. Expanded NKG2A/C+CD122+CD8+ T cells in RhCMV-infected macaques, but not their NKG2-negative counterparts, were endowed with cytotoxicity against class I-deficient K562 targets and prompt IFN-γ production in response to stimulation with IL-12 and IL-18. Because RhCMV clone 68-1 forms the viral backbone of RhCMV-vectored SIV vaccines, we also investigated immune changes following administration of RhCMV 68-1-vectored SIV vaccines. These vaccines led to impressive expansion of NKG2A/C+CD8+ T cells with capacity to inhibit SIV replication ex vivo. Thus, CMV infection and CMV-vectored vaccination drive expansion of functional innate-like CD8 cells via host IL-15 production, suggesting that innate-memory expansion could be achieved by other vaccine platforms expressing IL-15.

Orf virus: A promising new therapeutic agent

The orf virus (ORFV) is a zoonotic, epitheliotropic, DNA parapoxvirus that infects principally sheep and goats. Exposure of animals to the virus or immunization by an ORFV preparation can accentuate the severity of disease, which has provoked an interest in the underlying cellular, virological, and molecular mechanisms. The identified ORFV virulence genes and the fact that the virus can repeatedly infect a host, owing to its evasive mechanisms, contribute to the development of potent immune modulators in various animal species. ORFV has been developed as a vaccine in veterinary medicine. The unique host immune-evasion ability of ORFV has made it an important candidate for vaccine vectors and biological agents (as an oncolytic virus). Genetic modifications using ORFV to obtain safe and efficient preparations and mechanistic studies are improvements to the currently available methods for disease treatment.

Wound healing in cutaneous leishmaniasis: A double edged sword of IL-10 and TGF-β

Immune responses have a crucial role during the wound healing process in cutaneous leishmaniasis (CL). However, there are several paradoxes in immunity against CL. On the one hand, regulatory cytokines interleukin (IL)-10 and transforming growth factor beta (TGF-β) increase susceptibility to CL through suppression of several proinflammatory cytokines that require for defense against CL. On the other hand, these cytokines play a pivotal role in the acceleration of wound healing process. This review discusses about the dual role of IL-10 and TGF-β during the wound healing process and immunity against CL to offer a new insight about wound healing in CL.

The MAPK-Activated Kinase MK2 Attenuates Dendritic Cell-Mediated Th1 Differentiation and Autoimmune Encephalomyelitis

Dendritic cell (DC)-mediated inflammation induced via TLRs is promoted by MAPK-activated protein kinase (MK)-2, a substrate of p38 MAPK. In this study we show an opposing role of MK2, by which it consolidates immune regulatory functions in DCs through modulation of p38, ERK1/2-MAPK, and STAT3 signaling. During primary TLR/p38 signaling, MK2 mediates the inhibition of p38 activation and positively cross-regulates ERK1/2 activity, leading to a reduction of IL-12 and IL-1α/β secretion. Consequently, MK2 impairs secondary autocrine IL-1α signaling in DCs, which further decreases the IL-1α/p38 but increases the anti-inflammatory IL-10/STAT3 signaling route. Therefore, the blockade of MK2 activity enables human and murine DCs to strengthen proinflammatory effector mechanisms by promoting IL-1α-mediated Th1 effector functions in vitro. Furthermore, MK2-deficient DCs trigger Th1 differentiation and Ag-specific cytotoxicity in vivo. Finally, wild-type mice immunized with LPS in the presence of an MK2 inhibitor strongly accumulate Th1 cells in their lymph nodes. These observations correlate with a severe clinical course in DC-specific MK2 knockout mice compared with wild-type littermates upon induction of experimental autoimmune encephalitis. Our data suggest that MK2 exerts a profound anti-inflammatory effect that prevents DCs from prolonging excessive Th1 effector T cell functions and autoimmunity.

The complete genome sequences of poxviruses isolated from a penguin and a pigeon in South Africa and comparison to other sequenced avipoxviruses

Background

Two novel avipoxviruses from South Africa have been sequenced, one from a Feral Pigeon (Columba livia) (FeP2) and the other from an African penguin (Spheniscus demersus) (PEPV). We present a purpose-designed bioinformatics pipeline for analysis of next generation sequence data of avian poxviruses and compare the different avipoxviruses sequenced to date with specific emphasis on their evolution and gene content.

Results

The FeP2 (282 kbp) and PEPV (306 kbp) genomes encode 271 and 284 open reading frames respectively and are more closely related to one another (94.4%) than to either fowlpox virus (FWPV) (85.3% and 84.0% respectively) or Canarypox virus (CNPV) (62.0% and 63.4% respectively). Overall, FeP2, PEPV and FWPV have syntenic gene arrangements; however, major differences exist throughout their genomes. The most striking difference between FeP2 and the FWPV-like avipoxviruses is a large deletion of ~16 kbp from the central region of the genome of FeP2 deleting a cc-chemokine-like gene, two Variola virus B22R orthologues, an N1R/p28-like gene and a V-type Ig domain family gene. FeP2 and PEPV both encode orthologues of vaccinia virus C7L and Interleukin 10. PEPV contains a 77 amino acid long orthologue of Ubiquitin sharing 97% amino acid identity to human ubiquitin.

Conclusions

The genome sequences of FeP2 and PEPV have greatly added to the limited repository of genomic information available for the Avipoxvirus genus. In the comparison of FeP2 and PEPV to existing sequences, FWPV and CNPV, we have established insights into African avipoxvirus evolution. Our data supports the independent evolution of these South African avipoxviruses from a common ancestral virus to FWPV and CNPV.

Pathogen manipulation of cIL-10 signaling pathways: opportunities for vaccine development?

Interleukin-10 (IL-10) is a tightly regulated, pleiotropic cytokine that has profound effects on all facets of the immune system, eliciting cell-type-specific responses within cells expressing the IL-10 receptor (IL-10R). It is considered a master immune regulator, and imbalances in IL-10 expression, resulting from either inherent or infectious etiologies, have far reaching clinical ramifications. Regarding infectious diseases, there has been accumulating recognition that many pathogens, particularly those that establish lifelong persistence, share a commonality of their natural histories: manipulation of IL-10-mediated signaling pathways. Multiple viral, bacterial, protozoal, and fungal pathogens appear to have evolved mechanisms to co-opt normal immune functions, including those involving IL-10R-mediated signaling, and immune effector pathways away from immune-mediated protection toward environments of immune evasion, suppression, and tolerance. As a result, pathogens can persist for the life of the infected host, many of whom possess otherwise competent immune systems. Because of pathogenic avoidance of immune clearance, persistent infections can exact incalculable physical and financial costs, and represent some of the most vexing challenges for improvements in human health. Enormous benefits could be gained by the development of efficient prevention and/or therapeutic strategies that block primary infection, or clear the infection. There are now precedents that indicate that modalities focusing on pathogen-mediated manipulation of IL-10 signaling may have clinical benefit.

IL-10: achieving balance during persistent viral infection

The clearance of viral infections is reliant on the coordination and balance of inflammatory factors necessary for viral destruction and immunoregulatory mechanisms necessary to prevent host pathology. In the case of persistent viral infections, immunoregulatory pathways prevent the immune response from clearing the virus, resulting in a long-term equilibrium between host and pathogen. Consequently, negative immune regulators are being considered as a therapeutic target to treat persistent and chronic viral infections. In this review, we will highlight the current understanding of the important negative immune regulator interleukin-10 (IL-10) in persistent viral infection. Though its main role for the host is to limit immune-mediated pathology, IL-10 is a multifunctional cytokine that differentially regulates a number of different hematopoietic cell types. IL-10 has been shown to play a role in a number of infectious diseases and many viral pathogens specifically exploit the IL-10 pathway to help evade host immunity. Recent advances have demonstrated that manipulation of IL-10 signaling during persistent viral infection can alter T cell responses in vivo and that this manipulation can lead to the clearance of persistent viral infection. Furthermore, there have been crucial advances in the understanding of factors that induce IL-10. We summarize lessons learned about IL-10 in model organisms and human persistent infections and conclude with the potential use of IL-10 to treat persistent viral infections.

IL-10 encoded by viruses: a remarkable example of independent acquisition of a cellular gene by viruses and its subsequent evolution in the viral genome

Many viruses have evolved strategies to deregulate the host immune system. These strategies include mechanisms to subvert or recruit the host cytokine network. IL-10 is a pleiotropic cytokine that has both immunostimulatory and immunosuppressive properties. However, its key features relate mainly to its capacity to exert potent immunosuppressive effects. Several viruses have been shown to upregulate the expression of cellular IL-10 (cIL-10) with, in some cases, enhancement of infection by suppression of immune functions. Other viruses encode functional orthologues of cIL-10, called viral IL-10s (vIL-10s). The present review is devoted to these virokines. To date, vIL-10 orthologues have been reported for 12 members of the family Herpesviridae, two members of the family Alloherpesviridae and seven members of the family Poxviridae. Study of vIL-10s demonstrated several interesting aspects on the origin and the evolution of these viral genes, e.g. the existence of multiple (potentially up to nine) independent gene acquisition events at different times during evolution, viral gene acquisition resulting from recombination with cellular genomic DNA or cDNA derived from cellular mRNA and the evolution of cellular sequence in the viral genome to restrict the biological activities of the viral orthologues to those beneficial for the virus life cycle. Here, various aspects of the vIL-10s described to date are reviewed, including their genetic organization, protein structure, origin, evolution, biological properties and potential in applied research.

Horizontal transfer and the evolution of host-pathogen interactions

Horizontal gene transfer has been long known in viruses and prokaryotes, but its importance in eukaryotes has been only acknowledged recently. Close contact between organisms, as it occurs between pathogens and their hosts, facilitates the occurrence of DNA transfer events. Once inserted in a foreign genome, DNA sequences have sometimes been coopted by pathogens to improve their survival or infectivity, or by hosts to protect themselves against the harm of pathogens. Hence, horizontal transfer constitutes a source of novel sequences that can be adopted to change the host-pathogen interactions. Therefore, horizontal transfer can have an important impact on the coevolution of pathogens and their hosts.

Serum IL-10 from systemic lupus erythematosus patients suppresses the differentiation and function of monocyte-derived dendritic cells

The role played by cytokines, other than interferon (IFN)-α, in the differentiation and function of dendritic cells (DCs) in systemic lupus erythematosus (SLE), remains unclear. Serum interleukin-10 (IL-10) levels are generally elevated in SLE patients, which might modulate the differentiation of DCs. In this study, DCs were induced from monocytes either by transendothelial trafficking or by culture with granulocyte-macrophage colony-stimulating factor (GM-CSF) + IL-4 + tumor necrosis factor (TNF)-α. Both systems were used to investigate the effects of elevated serum IL-10 level on DC differentiation in SLE patients. The results showed that monocyte-derived DCs induced by either SLE serum or exogenous IL-10 reduced the expression of human leukocyte antigen (HLA)-DR and CD80, decreased IL-12p40 level, and increased IL-10 level, and exhibited an impaired capacity to stimulate allogenic T-cell proliferation. These results indicate that serum IL-10 may be involved in the pathogenesis of SLE by modulating the differentiation and function of DCs.

Infected CD8α- dendritic cells are the predominant source of IL-10 during establishment of persistent viral infection

Interleukin-10 (IL-10) is an important factor involved in T-cell dysfunction during persistent viral infection. Although several factors can negatively regulate T-cell activity, targeting of the IL-10 pathway alone is sufficient to regenerate T-cell activity and increase viral control. How IL-10 mediates these effects is unclear. Here, we investigated the cellular source of IL-10 necessary for establishing T-cell exhaustion and viral persistence, using IL-10 reporter mice (VertX), cell-type-specific IL-10 and IL-10 receptor deletion mice, and bone marrow chimeric mice. During establishment of viral persistence, the cellular subset with the most prevalent expression of IL-10 was CD8α(-)CD4(+) dendritic cells (DCs), which produced IL-10 with increasing kinetics until 9 d postinfection. After this time point, DCs exhibited a modest decline in percentage of IL-10(+) cells whereas B cells and CD4(+) T cells increased minimally. Further analysis of the DC population demonstrated that IL-10 was primarily expressed in infected DCs. These DCs were a notable source of IL-10 as mutant mice with a DC-specific deletion of IL-10 had significantly decreased serum levels. Interestingly, viral infection was not directly causative of IL-10 expression; rather, IL-10 production appeared to be linked to type I IFN signaling. Our findings further illuminate the contribution of DCs to the production of IL-10 and to viral persistence.

Infection of nonhost species dendritic cells in vitro with an attenuated myxoma virus induces gene expression that predicts its efficacy as a vaccine vector

Recombinant myxoma virus (MYXV) can be produced without a loss of infectivity, and its highly specific host range makes it an ideal vaccine vector candidate, although careful examination of its interaction with the immune system is necessary. Similar to rabbit bone marrow-derived dendritic cells (BM-DCs), ovine dendritic cells can be infected by SG33, a MYXV vaccine strain, and support recombinant antigen expression. The frequency of infected cells in the nonhost was lower and the virus cycle was abortive in these cell types. Among BM-DC subpopulations, Langerhans cell-like DCs were preferentially infected at low multiplicities of infection. Interestingly, ovine BM-DCs remained susceptible to MYXV after maturation, although apoptosis occurred shortly after infection as a function of the virus titer. When gene expression was assessed in infected BM-DC cultures, type I interferon (IFN)-related and inflammatory genes were strongly upregulated. DC gene expression profiles were compared with the profiles produced by other poxviruses in interaction with DCs, but very few commonalities were found, although genes that were previously shown to predict vaccine efficacy were present. Collectively, these data support the idea that MYXV permits efficient priming of adaptive immune responses and should be considered a promising vaccine vector along with other poxviruses.

CD83 increases MHC II and CD86 on dendritic cells by opposing IL-10-driven MARCH1-mediated ubiquitination and degradation

Effective vaccine adjuvants must induce expression of major histocompatibility (MHC) class II proteins and the costimulatory molecule CD86 on dendritic cells (DCs). However, some adjuvants elicit production of cytokines resulting in adverse inflammatory consequences. Development of agents that selectively increase MHC class II and CD86 expression without triggering unwanted cytokine production requires a better understanding of the molecular mechanisms influencing the production and degradation of MHC class II and CD86 in DCs. Here, we investigate how CD83, an immunoglobulin protein expressed on the surface of mature DCs, promotes MHC class II and CD86 expression. Using mice with an N-ethyl-N-nitrosourea-induced mutation eliminating the transmembrane (TM) region of CD83, we found that the TM domain of CD83 enhances MHC class II and CD86 expression by blocking MHC class II association with the ubiquitin ligase MARCH1. The TM region of CD83 blocks interleukin 10-driven, MARCH1-dependent ubiquitination and degradation of MHC class II and CD86 in DCs. Exploiting this posttranslational pathway for boosting MHC class II and CD86 expression on DCs may provide an opportunity to enhance the immunogenicity of vaccines.

Pollen-derived low-molecular weight factors inhibit 6-sulfo LacNAc+ dendritic cells' capacity to induce T-helper type 1 responses

BACKGROUND

Evidence is accumulating that the pollen exsudate contains an array of non-allergenic, pro-inflammatory and immunomodulatory substances acting on the innate and adaptive immune system. In this context, pollen-associated E(1)-phytoprostanes (PPE(1)) were shown to licence human monocyte-derived dendritic cells for T-helper type 2 (Th2) polarization of naïve T cells.

OBJECTIVE

This study aims at analysing the impact of pollen-associated lipid mediators on cytokine secretion and maturation of 6-sulfo LacNAc(+) dendritic cells (slanDCs), the most abundant native dendritic cell (DC) in human peripheral blood, and further dissecting the biologically active substance(s) within aqueous pollen extracts.

RESULTS

Aqueous birch pollen extracts dose-dependently inhibited the lipopolysaccharide (LPS)-induced IL-12 p70 production, while the levels of IL-6 remained unaffected. PPE(1) inhibited secretion of both IL-12 p70 and IL-6. Aqueous pollen extracts, but not PPE(1) or F(1)-phytoprostanes significantly reduced the LPS-induced surface expression of the maturation markers CD80, CD83, CD40 and CCR-7, an effect that was independent of proteins and that was still present in a 3 kDa cut-off fraction of the pollen extract. These effects were observed irrespective of the atopy status of the donors. Finally, slanDCs exposed to aqueous pollen extracts were impaired in eliciting an IFN-gamma response in naïve CD4(+) T cells.

CONCLUSION

Our data show that slanDCs, a subset of human blood DCs with constitutively high potency to induce Th1 responses, are susceptible to the Th2 polarizing effect of low molecular weight, non-protein factors derived from pollen.

Identification of multiple independent horizontal gene transfers into poxviruses using a comparative genomics approach

Background

Poxviruses are important pathogens of humans, livestock and wild animals. These large dsDNA viruses have a set of core orthologs whose gene order is extremely well conserved throughout poxvirus genera. They also contain many genes with sequence and functional similarity to host genes which were probably acquired by horizontal gene transfer.

Although phylogenetic trees can indicate the occurrence of horizontal gene transfer and even uncover multiple events, their use may be hampered by uncertainties in both the topology and the rooting of the tree. We propose to use synteny conservation around the horizontally transferred gene (HTgene) to distinguish between single and multiple events.

Results

Here we devise a method that incorporates comparative genomic information into the investigation of horizontal gene transfer, and we apply this method to poxvirus genomes. We examined the synteny conservation around twenty four pox genes that we identified, or which were reported in the literature, as candidate HTgenes. We found support for multiple independent transfers into poxviruses for five HTgenes. Three of these genes are known to be important for the survival of the virus in or out of the host cell and one of them increases susceptibility to some antiviral drugs.

Conclusion

In related genomes conserved synteny information can provide convincing evidence for multiple independent horizontal gene transfer events even in the absence of a robust phylogenetic tree for the HTgene.

Infection with recombinant orf viruses demonstrates that the viral interleukin-10 is a virulence factor

Orf virus is the prototype parapoxvirus that causes the contagious skin disease orf. It encodes an orthologue of the cytokine interleukin (IL)-10. Recombinant orf viruses were constructed in which the viral interleukin-10 (vorfIL-10) was disabled (vorfIL-10ko) and reinserted (vorfrevIL-10) at the same locus and compared to wild-type virus for their ability to induce skin lesions in sheep. After either primary infection or reinfection, smaller less severe lesions were recorded in the vorfIL-10ko-infected animals compared with either of the vorfIL-10-intact virus-infected animals. Thus, the vorfIL-10ko virus was attenuated compared with the vorfIL-10 intact viruses, demonstrating that orf virus IL-10 is a virulence factor. The virus IL-10 is one of several virulence or immuno-modulatory factors expressed by orf virus. Removal of any one of these genes would be expected to have only a partial effect on virulence, which is what was observed in this study with vorfIL-10.

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

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.