The elaborate interplay of natural killer cells and vaccinia virus

Vaccinia virus (VACV) is a poxvirus and is the vaccine used to eradicate smallpox. It is also an expression vector for heterologous antigens and an oncolytic virus for cancer therapy. VACV encodes multiple proteins that aid evasion of the host immune response. There is, however, an incomplete understanding of how this immune suppression by VACV is consistent with such a strong immune response and subsequent memory. There is especially little known about the relationship between natural killer (NK) cells and VACV. Previous studies showed that during VACV infection, NK cells proliferate, are activated, limit viral replication, kill VACV-infected cells and display memory-like qualities. However, how NK cells recognise and interact with VACV-infected cells, which ligand(s) trigger NK cell activation, which NK receptors (NKR) are involved, and whether VACV uses strategies to interfere with the NK cell response remains elusive. This thesis aimed to address such questions using screening methods in parallel to candidate-based approach to tackle the challenges caused by the high diversity of NKRs and NK ligands. First, the responsiveness of murine NK cells to systemic VACV infection was studied ex vivo. Transcriptomic analysis, along with validation at the protein level, indicated NK cell activation and preparedness to mediate effector functions. Analysis of NK cell transcriptomic signature indicated that the stimuli triggering NK cell activation in the context of VACV infection correspond primarily with direct cell recognition but also cytokines such as Il-12 and -18, and IFNs. NKRs expression level in response to VACV was investigated, both at the transcript and protein level, and candidate NKRs involved specifically in the response to VACV were defined. Using a published dataset, the human and murine NK cell response to VACV was compared, revealing strong similarities. Second, the modulation of the plasma membrane (PM) proteome after VACV infection was studied using a proteomic screen that allowed to i) determine how VACV affects NK ligands expression; ii) give insights into VACV host surface protein modulation mechanism; iii) highlight previously unrecognised VACV strategies to evade NK cell response, iv) establish for the first time, a comprehensive analysis of VACV proteins expressed at the host PM and, v) suggest VACV surface proteins that potentially engage with NK cells. Third, the impact of the absence of VACV A56, an NK ligand candidate, and the murine natural cytotoxicity receptor (NCR) NKp46, were studied, in vitro and in vivo, in the context of VACV infection. This confirmed that VACV A56 prevents cell fusion, anchors VACV K2 and VCP (virus complement control protein) at the cell surface and enhances the binding of human and murine NCRs to VACV-infected cells. Further, it revealed that A56 deletion did not affect plaque size or EEV (extracellular enveloped virus) release, did not alter NK ligands surface expression, but led to decreased VACV-infected cells killing by murine NK cells. Lastly, the impact of VACV A56 and NKp46 deletion, on VACV infection outcome were assessed in vivo, in the acute and the memory stage and did not reveal substantial differences. Collectively, these data constitute a valuable resource concerning the interaction of VACV with NK cells and the factors influencing their interplay. These data can contribute to improve the development of VACV-based vaccines vectors and oncolytic viruses, and further our understanding of host-pathogen interactions

Transcriptional reprogramming of natural killer cells by vaccinia virus shows both distinct and conserved features with mCMV.

Natural killer (NK) cells have an established role in controlling poxvirus infection and there is a growing interest to exploit their capabilities in the context of poxvirus-based oncolytic therapy and vaccination. How NK cells respond to poxvirus-infected cells to become activated is not well established. To address this knowledge gap, we studied the NK cell response to vaccinia virus (VACV) in vivo, using a systemic infection murine model. We found broad alterations in NK cells transcriptional activity in VACV-infected mice, consistent with both direct target cell recognition and cytokine exposure. There were also alterations in the expression levels of specific NK surface receptors (NKRs), including the Ly49 family and SLAM receptors, as well as upregulation of memory-associated NK markers. Despite the latter observation, adoptive transfer of VACV-expercienced NK populations did not confer protection from infection. Comparison with the NK cell response to murine cytomegalovirus (MCMV) infection highlighted common features, but also distinct NK transcriptional programmes initiated by VACV. Finally, there was a clear overlap between the NK transcriptional response in humans vaccinated with an attenuated VACV, modified vaccinia Ankara (MVA), demonstrating conservation between the NK response in these different host species. Overall, this study provides new data about NK cell activation, function, and homeostasis during VACV infection, and may have implication for the design of VACV-based therapeutics

NKG2A Immune Checkpoint in Vδ2 T Cells: Emerging Application in Cancer Immunotherapy.

Peer reviewed: TrueFunder: University of MilanImmune regulation has revolutionized cancer treatment with the introduction of T-cell-targeted immune checkpoint inhibitors (ICIs). This successful immunotherapy has led to a more complete view of cancer that now considers not only the cancer cells to be targeted and destroyed but also the immune environment of the cancer cells. Current challenges associated with the enhancement of ICI effects are increasing the fraction of responding patients through personalized combinations of multiple ICIs and overcoming acquired resistance. This requires a complete overview of the anti-tumor immune response, which depends on a complex interplay between innate and adaptive immune cells with the tumor microenvironment. The NKG2A was revealed to be a key immune checkpoint for both Natural Killer (NK) cells and T cells. Monalizumab, a humanized anti-NKG2A antibody, enhances NK cell activity against various tumor cells and rescues CD8 αβ T cell function in combination with PD-1/PD-L1 blockade. In this review, we discuss the potential for targeting NKG2A expressed on tumor-sensing human γδ T cells, mostly on the specific Vδ2 T cell subset, in order to emphasize its importance and potential in the development of new ICI-based therapeutic approaches

NKG2A Immune Checkpoint in Vδ2 T Cells: Emerging Application in Cancer Immunotherapy

Immune regulation has revolutionized cancer treatment with the introduction of T-cell-targeted immune checkpoint inhibitors (ICIs). This successful immunotherapy has led to a more complete view of cancer that now considers not only the cancer cells to be targeted and destroyed but also the immune environment of the cancer cells. Current challenges associated with the enhancement of ICI effects are increasing the fraction of responding patients through personalized combinations of multiple ICIs and overcoming acquired resistance. This requires a complete overview of the anti-tumor immune response, which depends on a complex interplay between innate and adaptive immune cells with the tumor microenvironment. The NKG2A was revealed to be a key immune checkpoint for both Natural Killer (NK) cells and T cells. Monalizumab, a humanized anti-NKG2A antibody, enhances NK cell activity against various tumor cells and rescues CD8 αβ T cell function in combination with PD-1/PD-L1 blockade. In this review, we discuss the potential for targeting NKG2A expressed on tumor-sensing human γδ T cells, mostly on the specific Vδ2 T cell subset, in order to emphasize its importance and potential in the development of new ICI-based therapeutic approaches

NKG2A Immune Checkpoint in Vδ2 T Cells: Emerging Application in Cancer Immunotherapy.

Immune regulation has revolutionized cancer treatment with the introduction of T-cell-targeted immune checkpoint inhibitors (ICIs). This successful immunotherapy has led to a more complete view of cancer that now considers not only the cancer cells to be targeted and destroyed but also the immune environment of the cancer cells. Current challenges associated with the enhancement of ICI effects are increasing the fraction of responding patients through personalized combinations of multiple ICIs and overcoming acquired resistance. This requires a complete overview of the anti-tumor immune response, which depends on a complex interplay between innate and adaptive immune cells with the tumor microenvironment. The NKG2A was revealed to be a key immune checkpoint for both Natural Killer (NK) cells and T cells. Monalizumab, a humanized anti-NKG2A antibody, enhances NK cell activity against various tumor cells and rescues CD8 αβ T cell function in combination with PD-1/PD-L1 blockade. In this review, we discuss the potential for targeting NKG2A expressed on tumor-sensing human γδ T cells, mostly on the specific Vδ2 T cell subset, in order to emphasize its importance and potential in the development of new ICI-based therapeutic approaches

Isolation of Uterine Innate Lymphoid Cells for Analysis by Flow Cytometry.

Described here is a simple method to isolate and phenotype mouse group 1 uterine innate lymphoid cells (g1 uILCs) from individual pregnant uterus by flow cytometry. The protocol describes how to set up time mating to obtain multiple synchronous dams, the mechanical and enzymatic digestion of the pregnant uterus, the staining of single-cell suspensions, and a FACS strategy to phenotype and discriminate g1 uILCs. Although this method inevitably loses the spatial information of cellular distribution within the tissue, the protocol has been successfully applied to determine uILC heterogeneity, their response to maternal and foetal factors affecting pregnancy, their gene expression profile, and their functions.Our lab is supported by a Wellcome Investigator Award (200841/Z/16/Z), and an MRC project grant (MR/P001092/1

Selective modulation of cell surface proteins during vaccinia infection: implications for immune evasion strategies

The interaction between immune cells and virus-infected targets involves multiple plasma membrane (PM) proteins. A systematic study of PM protein modulation by vaccinia virus (VACV), the paradigm of host regulation, has the potential to reveal not only novel viral immune evasion mechanisms, but also novel factors critical in host immunity. Here, >1000 PM proteins were quantified throughout VACV infection, revealing selective downregulation of known T and NK cell ligands including HLA-C, downregulation of cytokine receptors including IFNAR2, IL-6ST and IL-10RB, and rapid inhibition of expression of certain protocadherins and ephrins, candidate activating immune ligands. Downregulation of most PM proteins occurred via a proteasome-independent mechanism. Upregulated proteins included a decoy receptor for TRAIL. Twenty VACV-encoded PM proteins were identified, of which five were not recognised previously as such. Collectively, this dataset constitutes a valuable resource for future studies on antiviral immunity, host-pathogen interaction, poxvirus biology, vector-based vaccine design and oncolytic therapy

Pièges diagnostiques de la GEM idiopathique: à propos de trois cas

info:eu-repo/semantics/publishe

Diagnostic trap for Idiopathic Membranous Nephropathy: about 3 cases

info:eu-repo/semantics/nonPublishe