The advancement of cancer immunotherapy, especially in the manipulation of NK cells, holds promise for targeted cancer treatment. NK cell effectiveness is currently assessed using cell populations in cytotoxicity assays, but these lack the details to observe individual cellular behaviours in real time. Droplet-based microfluidics is emerging as a solution to address these limitations by allowing the encapsulation of cells at specific ratios in controlled microenvironments. This advancement enhances the accuracy of immunotherapeutic assessments by providing a more detailed understanding of cellular interactions. In our study, we employed droplet microfluidics to encapsulate and analyze the interactions between NK cells and K562 cancer cells at predetermined effector-to-target (E:T) ratios. Each droplet served as an isolated microreactor, where individual NK cell interactions with cancer cells could be monitored in real-time. The results of our study revealed that droplet-based microfluidics provide detailed insights into the differential cytotoxic capacities of primary (Pri), suppressed (Supp), expanded (Exp), and post-expansion suppressed (PES) NK cells. Notably, expanded NK cells exhibited not only higher cytotoxic activity at a faster rate but also greater serial killing capabilities across different donors and varying E:T ratios, indicating their potential for effective immunotherapy. Additionally, suppressed NK cells showed reduced cytotoxic abilities, emphasizing the importance of overcoming the suppressive factors within the tumour microenvironment. These findings are pivotal for the field of immunotherapy and hold promising implications for the selection and optimization of NK cell-based treatments tailored to individual patient needs. / Thesis / Master of Applied Science (MASc)

v anglickém jazyce NK cells represent a population of lymphocytes which are able to kill certain tumor cells or virally infected cells. The subject of the diploma thesis is a mouse NK cell receptor mNKR- P1CBALB and a human leukocyte receptor hAICL. The mNKR-P1CBALB belongs to the activating receptors and is able to activate the cytotoxic functions of NK cells. The hAICL receptor is a ligand to the NKp80 which is an activating receptor of NK cells. Interaction between these two proteins leads to the activation of effector functions of NK cells as well. The aim of this work was the preparation of the recombinant extracellular parts of receptors mNKR-P1CBALB and hAICL, the optimalization of their in vitro refolding and the characterization of proteins using mass spectrometry. The proteins samples will be used for further structural study of the extracellular parts of these leukocytes receptors.

No description available.

Natural killer (NK) cells are lymphocytes of the innate immune system that play a major role in the destruction of both tumours and virally-infected cells. The cytotoxicity of NK cells is tightly controlled by signals received through activating and inhibitory receptors. NK cells express a variety of inhibitory receptors such as Ly49 receptors. Ly49 receptors bind to class I MHC molecules that expressed on normal cells. Using Ly49-deficient (NKCKD) mice we show that Ly49-KD NK cells successfully recognize and kill influenza virus-infected cells and that NKCKD mice exhibit better survival than wild-type mice. Moreover, influenza virus infection has a propensity to upregulate cell surface expression of MHC-I on murine lung epithelial cells in vivo. Significantly, we demonstrate increased lung damage of WT-mice versus NKCKD mice after influenza virus infection as determined by histological analyses. This data indicated that absence of Ly49 inhibitory NK receptors greatly enhances survival of infected mice.

The first half of this thesis addressed the clinical question of whether the phenotype of peripheral immune cells is affected by the normal menstrual cycle and whether there are differences in women with recurrent unexplained miscarriage. In chapter 2, a mid-luteal type 1 shift was demonstrated in NK^dim and cytotoxic T cells in the menstrual cycle. In addition, women with recurrent miscarriage had increased numbers of type 1 (IL-18R+) cytotoxic lymphocytes and an increased number of NK^dim and NK^bright cells in the mid-luteal phase of the cycle. The shift to type 2 immunity seen in normal pregnancy has been previously identified from the second half of the first trimester. In chapter 3 this type 2 shift was seen in NK and T cells as early as 9 days post implantation. ST2L (the ligand for IL-33 and a marker of type 2 cells) was consistently up regulated at this very early stage post implantation in women who were pregnant. The second half of this thesis investigated IL-33 and ST2 in normal and pathological pregnancy. In chapter 4 it was shown that circulating IL-33 did not change over the course of pregnancy but that sST2 (the soluble decoy receptor) increased significantly in the 3rd trimester of normal pregnancy. Both IL-33 and ST2 were variably expressed by the pre-implantation human blastocyst, as well as by the 1st and 3rd trimester placenta. Finally, chapter 5 showed a potential role for ST2 in pre-eclampsia, an inflammatory disease of pregnancy. sST2 was significantly elevated in the third trimester in women who went on to develop pre-eclampsia even prior to the onset of disease. Using an in vitro model of placental perfusion, it was shown that sST2 can be secreted by the placenta, suggesting that sST2 may play a significant role in pregnancies complicated by this disease.

Chronic Hepatitis B (CHB) related cirrhosis and hepatocellular carcinoma (HCC) account for more than 750,000 deaths per year. Current therapies for CHB are limited in achieving HBsAg decline/loss and thus there remains a pressing need for curative treatment strategies. Although, Pegylated Interferon-α (Peg-IFNα) may be used, the majority of patients progress to nucleos(t)ide analogue (NUC) therapy due to treatment failure. Peg-IFNα and NUCs used in isolation act differentially on the immune response; Peg-IFNα induces NK cell activation and NUC therapy may partially restore T cell function. NK cells are important antiviral effectors, highly enriched in the liver, with the potential to regulate immunopathogenesis in persistent viral infections. Here we examined the NK cell pool in HBeAg-positive CHB patients treated with Peg-IFNα and whether changes in the NK cell repertoire are induced when patients are 'primed' with Peg-IFNα and importantly, whether these changes are sustained or further modulated long-term after switching to sequential NUC therapy. The cumulative expansion of CD56bright NK cells driven by 48-weeks of Peg-IFNα was maintained at higher than baseline levels throughout the subsequent 9 months of sequential NUCs. Peg- IFNα-expanded NK cells showed further augmentation in their expression of the activating NK cell receptors during sequential NUCs. The expansion in proliferating, functional NK cells and HBsAg reduction was greater and more pronounced following sequential NUCs than in patients treated with de novo NUCs. This highlights the potential benefit of Peg-IFNα- priming, providing mechanistic insights for the further optimisation of treatment strategies to achieve sustained responses. Sustained boosting of NK cells on sequential NUCs following Peg-IFNα-priming has not previously been described raising the potential of 'long-lived' NK cell populations in keeping with their emerging adaptive features. These findings provide a mechanistic and immunological rationale to explore combination/sequential treatment strategies for CHB, including on-treatment immune responses in the liver, whilst awaiting the emergence of new therapies in the field.

Les cellules Natural Killer (NK) sont de grands lymphocytes granuleux capables de rapidement éliminer des cellules tumorales et des cellules infectées par des virus sans immunisation au préalable. Au cours de ma thèse, j’ai analysé plusieurs paramètres impliqués dans la reconnaissance et la lyse des cellules de mélanome par les NK. J’ai montré à partir d’analyses ex vivo que les NK sanguines de patients atteints de mélanome métastatique (stade III-IV) présentent un faible potentiel lytique. Cependant, de telles NK provenant de patients mélanomes de tout stade clinique activées in vitro par de l’IL-2 lysent efficacement des lignées de mélanome métastatique. L’analyse du phénotype de NK circulantes de patients stade IV a montré une diminution de l’expression du récepteur activateur NKp46/NCR1 comparé aux NK de donneurs sains. J’ai également montré une corrélation positive entre l’expression du NKp46 à la surface des NK et la durée du stade IV. Pour caractériser les NK infiltrant le mélanome, J’ai analysé ex vivo les NK infiltrant des ganglions métastatiques (GG) provenant de 25 patients en stade III. Les GG de patients mélanomes contiennent une population unique de NK CD56brightCD16+ représentant 50% des NK dans ces GG qui expriment fortement les récepteurs NK NCR, NKG2D, KIRs et produisent une plus forte proportion de perforin comparée aux NK CD56brightCD16- ganglionnaires. Les NK immunsélectionnées à partir de GG et activées avec de l’IL-2 ou de l’IL-15 lysent rapidement et efficacement des lignées cellulaires de mélanome. Elles sont caractérisées par des capacités lytiques supérieures aux NK sanguines. De plus, afin d’évaluer l’impact des NK au cours du mélanome, j’ai analysé in situ les NK infiltrant des ganglions sentinelles positive et négatif ainsi que des tumeurs cutanées primaires. Les NK sont faibles dans les GS ; cependant nous avons montré que le nombre de NK infiltrant ces ganglions sentinelles est associé à une plus forte rechute à cinq ans des patients. Les cellules NK infiltrant les tumeurs cutanées sont présentes préférentiellement dans la zone peritumorale et sont très rares dans la tumeur.Chez les patients atteints de mélanome, les NK sanguines et infiltrant les tumeurs ont des caractéristiques phénotypiques et fonctionnelles différentes. Une meilleure compréhension de telles différences doit être prise en compte, ainsi la biologie des NK et de leur modulation au cours du cancer est nécessaire pour développer une stratégie thérapeutique à base de cellules NK efficace. / Cytotoxic immune effectors can control the development and growth of certain solid tumours. Among these cytotoxic effectors, NK cells are capable of rapidly eliminating tumour cells and virus-infected cells without prior immunization.The objectives of my thesis were to evaluate the potential role of NK cells in the immune response against melanoma. First, I have characterized the functional status of blood NK cells from melanoma patients at different stages of the disease. I showed that ex vivo NK cells from most advanced stage III-IV patients display low lytic potential. However, IL-2-activated NK cells from patients efficiently lyse melanoma cells and that independently to the clinical stage. Moreover, the expression of the activating receptor NKp46/NCR1 by blood NK cells was decreased in stage IV patients compared to healthy donors, and a positive correlation between NKp46 expression by NK cells and the duration of stage IV was found. I have also characterized ex vivo NK cells infiltrating metastatic lymph nodes (M-LN) from stage III melanoma patients. I have identified in M-LN a unique subpopulation of mature CD56brightCD16+ NK cells that expressed higher NCR, NKG2D, KIRs, and perforin levels than CD56brightCD16- NK cells counterpart. NK cells from M-LN activated with IL-2 or IL-15, rapidly lysed metastatic melanoma cell lines with higher efficiency than autologous blood NK cells. Finally, to determine if NK cells display a prognostic value, I analysed by immunohistochemistry NK cells and other immune cells infiltrating positive and negative sentinel lymph nodes (SLN). SLN are characterized by high densities of macrophages and endothelial cells, even higher in SLN+. Few NK cells and Granzyme B+ cells infiltrate SLNs while CD8+ T cells are numerous. Moreover, numbers of NK cells in SLN correlated with higher rate of 5 year-relapse of patients. Compared to SLN, primary cutaneous melanomas contain high numbers of NK cells that are preferentially localized in the periphery of the tumour and are not related to the Breslow. My findings showed that in melanoma patients, circulating and tumour infiltrating NK cells display unique phenotypic and functional characteristics, indicating that tumour may alter their function. However, they respond to cytokine activation and acquire antitumor lytic potential. In the new landscape of melanoma treatment, NK cells are worthy to be considered for combined treatment with BRAF inhibitors.

Natural killer (NK) cells are lymphocytes of the innate immune system that play a major role in the destruction of both tumours and virally-infected cells. The cytotoxicity of NK cells is tightly controlled by signals received through activating and inhibitory receptors. NK cells express a variety of inhibitory receptors such as Ly49 receptors. Ly49 receptors bind to class I MHC molecules that expressed on normal cells. Using Ly49-deficient (NKCKD) mice we show that Ly49-KD NK cells successfully recognize and kill influenza virus-infected cells and that NKCKD mice exhibit better survival than wild-type mice. Moreover, influenza virus infection has a propensity to upregulate cell surface expression of MHC-I on murine lung epithelial cells in vivo. Significantly, we demonstrate increased lung damage of WT-mice versus NKCKD mice after influenza virus infection as determined by histological analyses. This data indicated that absence of Ly49 inhibitory NK receptors greatly enhances survival of infected mice.

Nous avons montré que, dans l'intestin, les cellules exprimant le marqueur spécifique des lymphocytes Natural Killer (NK), NKp46 peuvent être divisées en deux compartiments, par rapport au facteur de transcription RORyt. Les cellules NKp46+RORyt- sont des cellules NK intestinales immatures. Cependant, les cellules NKp46+RORyt- s'apparentent aux cellules "lymphoid tissue-inducer" (LTi), puisqu'elles requièrent RORyt pour leur développement et produisent de l'IL-22, cytokine essentielle pour l'homéostasie et la réponse antimicrobienne épithéliale. Notre recherche actuelle vise à établir les relations ontogéniques et la signature génétique de ces cellules au niveau pan-génomique. La fonction in vivo des cellules NKp46+ intestinales est adressée dans un modèle unique d'infection par voie orale avec Listeria monocytogenes. L'ensemble de nos résultats a montré que les cellules NKp46+ ont une place légitime dans la famille émergente des cellules intestinales de l'immunité innée. / Natural Killer (NK) cells are NKp46+CD3- innate lymphocytes, which exhibit cytotoxicityand cytokine production, mainly IFN-γ, as major effector functions. In mammals, theexpression of natural cytotoxic receptor NKp46 is essentially restricted to NK cellcompartment. However, we showed that in mouse intestine, NKp46 marker defines aheterogeneous cell population, differentially expressing the retinoic acid orphan receptorRORγt. NKp46+RORγt- cells harbor reduced cytotoxicity and IFN-γ production, consistentwith an immature NK cell phenotype. In contrast, NKp46+RORγt+ cells resemble lymphoidtissue inducer cells (LTi) in their developmental requirement for RORγt and their ability toproduce IL-22. This cytokine is critical for epithelial homeostasis and antimicrobial responseat several epithelial sites.By using a genome wide profiling approach, we confirmed that gut NKp46+RORγt- cellsare the only gut NKp46+ cell population related to conventional splenic NK cells, while gutNKp46+RORγt+ cells are linked to LTi cells. Transcriptional signatures specific of distinct gutNKp46+ cell subsets are currently under intensive investigation in order to determine novelfunctional properties.We assessed gut NKp46+ cell subsets in vivo function during oral infection with entericpathogen Listeria monocytogenes (L.m.). Although immune responses to systemic L.minfection have been widely characterized in mice, L.m. cannot breach mouse intestinal barrier,thus limiting the knowledge of early immune responses at the natural site of infection. Using aunique transgenic mouse lineage restoring L.m. intestinal invasiveness, we showed that gutNKp46+RORγt- and NKp46+RORγ t+ cells respond to L.m. infection by producing IFN-γ andIL-22, respectively. Further investigation of the cellular mechanisms leading to gut NKp46+cell subset activation, as well as the contribution of these cells to the control of bacterialdissemination is in progress.Altogether our data provide novel insight into intestinal innate immunity and highlight gutNKp46+ cell subsets as “legitimate” members of the emerging family of intestinal innatelymphoid cells

La formation et le développement d’une tumeur sont provoqués par une série de défauts qui se produisent à l'intérieur de la cellule cancéreuse et dans son microenvironnement. Ces anomalies permettent à la cellule de développer ses propres stratégies de croissance, de prolifération, de différenciation et de métabolisme.La modification du métabolisme respiratoire, est l'une des stratégies utilisée par les cellules cancéreuses favorisant la fermentation lactique au lieu de la phosphorylation oxydative OXPHOS (respiration). Cette adaptation métabolique porte le nom d’effet Warburg.Nous avons proposé un concept thérapeutique novateur basé sur l'induction de changements métaboliques par l'utilisation de dichloroacétate (DCA) associée avec l'immunothérapie en utilisant les cellules NK activées. Le DCA, molécule inhibitrice de la PDK, induit l'activation de la PDH, responsable de la catalyse de pyruvate en Acétylcoenzyme A (Ac-CoA), favorise alors l’oxydation du glucose dans la mitochondrie. Le DCA a déjà été utilisé depuis longtemps comme traitement hypocholestérolémiant et bloquant l’acidose lactique. Mon équipe a montré auparavant que le changement métabolique permet aux cellules tumorales d'échapper à la réponse immune.Nous avons observé que le traitement par DCA induisait, dépendante du phénotype p53, une forte up-régulation de l'expression du mRNA et des protéines de stress MICA, MICB et ULBP1, ligands spécifiques des récepteurs activateurs NKG2D des cellules NK, et induise alors une réponse cytotoxique contre les cellules tumorale.D'autre part nous avons évalué l'effet de DCA sur l'expression des transporteurs ABC qui interviennent dans l'efflux des agents anticancéreux utilisé dans la chimiothérapie. L'expression des transporteurs ABC était fortement liée aux phénotypes de chimiorésistance. Nous avons bien confirmé que le DCA provoque une diminution de l'expression de ABCB1, ABCC1, ABCC5 et ABCG2 dans les cellules wtp53 alors qu'il induit une augmentation dans les cellules mutantp53 ou nullp53.Les promoteurs des transporteurs et les protéines de stress étudiés comportent également plusieurs sites de liaison spécifique au facteur de transcription MEF2, qui est la cible d’ERK5. Nous avons bien constaté que en plus de ca capacité de changer le métabolisme tumorale, le DCA modifie l'expression ABCB1, ABCC1, ABCC5 et ABCG2 par l'activation de la voie ERK5/MEF2 .Ces résultats sont confirmé dans diverses lignées cellulaires, ainsi que dans des cellules issues de patients et dans un modèle in vivo / Tumorigenesis is caused by a series of defects that occur within the cancer cell and its microenvironment. These abnormalities allow the tumor cell to develop its own strategies for growth, proliferation, differentiation and metabolism. In the last, cancer cells favor lactic fermentation instead of oxidative phosphorylation OXPHOS (respiration). This metabolic adaptation is called the Warburg effect.We proposed an innovative therapeutic concept based on the induction of metabolic changes by the use of dichloroacetate (DCA) and this is associated with immunotherapy using activated NK cells. DCA, a pyruvate dehydrogenase kinase (PDK) inhibitor, induces the activation of pyruvate dehydrogenase (PDH), responsible for the catalysis of pyruvate to acetylcoenzyme A (Ac-CoA), promoting the oxidation of glucose/pyruvate in the mitochondria. DCA has been used for a long time as a cholesterol-lowering and anti-lactic acidosis therapy. My team has previously shown that the metabolic change allows tumor cells to escape the immune response. I have observed that DCA treatment induced a high upregulation of mRNA and protein expression of the stress ligands MICA, MICB and ULBP1. These are recognized by the NK cell activating receptor NKG2D, inducing a NK cell-mediated cytotoxic response against tumor cells. DCA-induced expression of these stress ligands depends on wtp53 expression on the tumor cell.On the other hand, we evaluated the effect of DCA on the expression of ABC carriers, which intervene in the efflux of anticancer agents used in chemotherapy. The expression of ABC carriers is strongly related to drug resistance phenotypes. We observed that DCA causes a decrease in the expression of ABCB1, ABCC1, ABCC5 and ABCG2 in wtp53 cells while it induces an increase in mutantp53 or nullp53 cells. Conversely, DCA-induced accumulation of antitumor drugs, i.e. daunorubicin, and favors chemotherapy-induced tumor death only in wtp53-expressing cancer cells. The promoters of these ABC transporters and the stress proteins presented above contain several binding sites specific to the transcription factor MEF2, which is the target of ERK5. We have found that in addition to the ability to change tumor metabolism, DCA modifies the expression ABCB1, ABCC1, ABCC5 and ABCG2 by activation of the ERK5 / MEF2 pathway. These results are confirmed in various cell lines, in cells derived from patients and in an in vivo model