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

Multimodal Imaging in Parkinson's Disease

Présentation des résultats de travaux de recherche portant sur l'imagerie multimodale en Maladie de Parkinson, et plus particulièrement sur l'étude des relations entre l'IRM sensible au Fer, à la Neuromélanine et le PETscan cérébral à la FDOPA.New MRI biomarkers in Parkinson's Diseas

Sporadic Creutzfeldt-Jakob disease: a case study.

Description d'un cas clinique de maladie de Creutzfeldt-Jakob sporadique et discussion de son diagnostic différentiel (dont les encéphalites limbiques)

Drug-induced movement disorders : nosology and treatment.

editorial reviewedMovements disorders are frequently encountered in general practice and emergency departments and are in many cases of iatrogenic origin. Dopamine D2 receptor blocking agents (DRBA), mainly neuroleptics, are most often incriminated. These drug-induced movement disorders (DIMD) can be classified according to the kinetics of the manifestations (acute DIMD and tardive syndromes), the phenomenology of the abnormal movements observed or depending on the pharmacological agent involved. The diagnosis is based on the time course of the events, clinical examination and meticulous anamnesis of the patient's previous and current treatments. Management is always based on the interruption of the suspected causal treatment when possible. Some cases have a severe prognosis and require immediate treatment.Les mouvements anormaux sont fréquemment rencontrés en médecine générale et aux urgences et sont, dans de nombreux cas, d’origine iatrogène. Les molécules les plus souvent incriminées sont les agents bloqueurs des récepteurs dopaminergiques D2 (DRBA) et principalement les neuroleptiques. Ces mouvements anormaux iatrogènes (MAI) peuvent être classés selon la cinétique des manifestations (MAI aigus et syndromes tardifs), la sémiologie des mouvements observés, ou encore, selon l’agent pharmacologique en cause. Le diagnostic repose sur le décours temporel des manifestations, l’examen clinique et une anamnèse fouillée des traitements antérieurs et actuels du patient. La prise en charge repose toujours sur l’arrêt du traitement causal quand cela est possible. Il existe des situations urgentes grevées d’un pronostic sévère et redevables d’un traitement rapide