Cyprinid herpesvirus 3 : an intersting virus for applied and fundamental research

peer reviewe

Human cytokines activate JAK–STAT signaling pathway in porcine ocular tissue

Background: The JAK/STAT (Janus Tyrosine Kinase, Signal Transducers and Activators of Transcription) pathway is associated with cytokine or growth factor receptors and it is critical for growth control, developmental regulation and homeostasis. The use of porcine ocular cells as putative xenotransplants appears theoretically possible. The aim of this study was to investigate the response of various porcine ocular cells in vitro to human cytokines in regard to the activation of JAK-STAT signaling pathways. Methods: Porcine lens epithelial cells, pigmented iris epithelial cells and pigmented ciliary body cells were used in this study. These cells were isolated from freshly enucleated porcine eyes by enzymatic digestion. Cultured cells between passages 3–8 were used in all experiments. Electromobility shift assay (EMSA), proliferation assay, immunofluorescence staining and flow cytometry were used to evaluate the JAK-STAT signaling pathway in these cells. Results: JAK/STAT signaling pathways could be activated in porcine pigmented epithelial ciliary body cells, in pigmented iris epithelial cells and in lens epithelial cells in response to porcine and human interferons and cytokines. All cells showed very strong STAT1 activation upon stimulation with porcine interferon-gamma. Porcine ocular cells also respond to human cytokines; IFN-alpha induced strong activation of STAT1 in EMSA, flow cytometry and immunofluorescence experiments whereas activation of STAT3 was less strong in EMSA, but strong in flow cytometry and immunofluorescence. Human recombinant IL-6 activated STAT3 and human IL-4 activated STAT6. With the help of immunofluorescence assay and flow cytometry we observed nuclear localization of STAT proteins after activation of porcine ocular cells with cytokines and interferons. Human IFN-α had an inhibitory effect on porcine ocular cells in proliferation assays. Conclusion: Our study demonstrated that some types of human cytokines and interferon activate intracellular JAK-STAT signaling pathways in porcine ocular cells. We hypothesize that direct stimulation of the JAK-STAT pathway in porcine cells in response to human cytokines will lead to complications or failure, if pig-to-human ocular tissue xenotransplantation were to be carried out. For successful xenotransplantation among other obstacles there must be new approaches developed to regulate signaling pathways

Regulation of the Immune Response by Innate Lymphocyte and Dendritic Cell Cross Talk

Dendritic cell (DC) is the generic name of different professional antigen presenting cell sub-populations, which are responsible for the initiation of specific immune responses. Recently, DC have been involved in supporting innate immunity by interacting with various innate lymphocytes, such as natural killer (NK), NKT or γδ T (T cells expressing γδ T cell receptor). The functional links between innate lymphocytes and DC have been investigated widely and different studies demonstrated that the cross-talk between innate lymphocytes and DC was found to be multi-directional, involving not only cell-cell contacts but also soluble factors which lead to lymphocyte activation and DC maturation. The final outcome of these cellular interactions may have a dramatic impact on the quality and strength of the down-stream immune responses, mainly in the context of early responses to tumor cells and infectious agents. Interestingly, DC, NK and γδ T cells also share similar functions, such as antigen uptake and presentation, as well as cytotoxic and tumoricidal activity. In addition, NK and NKT cells have the ability to kill DC. This chapter will focus upon the different aspects of the cross-talk between DC and innate lymphocytes and its key role in all the steps of the immune response. These cellular interactions may be particularly critical in situations where immune surveillance requires efficient early innate responses

New dimensions in tumor immunology: what does 3D culture reveal?

Experimental models indicate that tumor cells in suspension, unlike solid tumor fragments, might be unable to produce life-threatening cancer outgrowth when transferred to animal models, irrespective of the number of cells transferred, although they induce specific immune responses. Human tumor cells cultured in three dimensions display increased pro-angiogenic capacities and resistance to interferons, chemotherapeutic agents or irradiation, as compared with cells cultured in two-dimensional (2D) monolayers. Tumor cells cultured in three dimensions were also shown to be characterized by defective immune recognition by cytotoxic T lymphocytes (CTLs) specific for tumor-associated antigens (TAAs) and by a capacity to inhibit CTL proliferation and dendritic cell (DC) functions. Downregulation of human leukocyte antigen (HLA) or TAA expression and high production of lactic acid might play a role in the elicitation of these effects. Here, we propose that growth in 3D architectures might provide new insights into tumor immunology and could represent an integral missing component in pathophysiological tumor immune escape mechanisms

Vaccine against human papillomavirus (HPV)-associated lesions induces collaboration between natural killer and dendritic cells in vitro.

Cervical cancer, the second most frequent gynaecological malignancy in the world, is caused by infection with high-risk human papillomaviruses (HPV). HPV16 and/or 18 are detected in more than 70% of these tumours. Prophylactic HPV-L1 virus like particle (VLP) vaccines are highly efficient to protect against HPV16 and HPV18 infection, but not against established infection. In this context, we study the effect of HPV-VLP on natural killer cells (NK) and on the crosstalk between NK and Dendritic Cells (DC). In order to know if HPV-VLP are able to enter in NK cells, we used fluorescent HPV-VLP with flow cytometry and confocal microscopy. HPV-VLP were internalised more rapidly in NK cells than in DC. They were already detected inside NK cells after 10 min of contact at 37°C. We also observed in CD107 assays, that HPV-VLP induce degranulation of NK cytotoxic granules. Previous works have shown that HPV-VLP were able to activate DC. We confirmed these results and observed an increase of CD69 cell surface expression and IFN-γ production by NK cells in the presence of DC activated by VLP. Interestingly, NK cells seemed to further activate DC in the presence of VLP as shown by an up-regulation of HLA-DR and CD86 on DC. Moreover, NK cells in the presence of HPV-VLP induced the production of IL12p70, but not the immunosuppressive cytokine IL10. Our results suggest that NK cells could play a role in the activation of DC induced by HPV-VLP during the vaccination against cervical cancer. Supported by the Belgian FNRS-Télévi

The IL-10 homologue encoded by cyprinid herpesvirus 3 is essential neither for viral replication in vitro nor for virulence in vivo

Cyprinid herpesvirus 3 (CyHV-3), a member of the family Alloherpesviridae, is the causative agent of a lethal disease in common and koi carp. CyHV-3 ORF134 encodes an interleukin-10 (IL-10) homologue. The present study was devoted to this ORF. Transcriptomic analyses revealed that ORF134 is expressed as a spliced gene belonging to the early-late class. Proteomic analyses of CyHV-3 infected cell supernatant demonstrated that the ORF134 expression product is one of the most abundant proteins of the CyHV-3 secretome. To investigate the role of ORF134 in viral replication in vitro and in virulence in vivo, a deleted strain and a derived revertant strain were produced using BAC cloning technologies. The recombinant ORF134 deleted strain replicated in vitro comparably to the parental and the revertant strains. Infection of fish by immersion in water containing the virus induced comparable CyHV-3 disease for the three virus genotypes tested (wild type, deleted and revertant). Quantification of viral DNA by real time TaqMan PCR (in the gills and the kidney) and analysis of carp cytokine expression (in the spleen) by RT-qPCR at different times post-infection did not revealed any significant difference between the groups of fish infected with the three virus genotypes. Similarly, histological examination of the gills and the kidney of infected fish revealed no significant differences between fish infected with ORF134 deleted virus versus fish infected with the control parental or revertant strains. All together, the results of the present study demonstrate that the IL-10 homologue encoded by CyHV-3 is essential neither for viral replication in vitro nor for virulence in common carp