Embora a obesidade esteja associada à disfunção imune, com incidência aumentada de infecções e alguns tipos de cânceres, há poucos estudos que avaliaram parâmetros imunológicos em pacientes obesos graves. Além disso, há um número limitado de trabalhos analisando o efeito da perda de peso sobre parâmetros imunológicos na obesidade grave. Desta forma, o objetivo do presente trabalho foi avaliar a influência da perda de peso de pacientes com obesidade grau III submetidos à cirurgia de derivação gastrojejunal em Y de Roux (DGJYR) em parâmetros imunológicos. A produção de citocinas associadas com a resposta imune adquirida (IL-2, IL-4, IL-10 e IFN-) e inata (TNF- e IL-6) por células mononucleares de sangue periférico (PBMC), o perfil das populações de linfócitos e a atividade citotóxica de células natural killer (NK), além de citocinas associadas a sua função e desenvolvimento (IL-12 e IL-18), foram avaliados em vinte e oito pacientes não diabéticos, sedentários, com obesidade grau III (20 mulheres e 8 homens, com média de idade de 39,9 ± 10,9 anos e IMC de 49,5 ± 7,1kg/m2) no pré-operatório e 6 meses após a cirurgia. As PBMC foram estimuladas com o mitógeno fitohemaglutinina (PHA) e as citocinas produzidas foram quantificadas por ELISA. O perfil das populações de linfócitos foi avaliado por citometria de fluxo. A citotoxicidade mediada por células NK foi determinada pelo ensaio de liberação de LDH por células alvo K562. A perda de peso foi de 35,3 ± 4,5 kg, com uma significativa redução no IMC seis meses após a cirurgia (-12,9 ± 0,9 kg/m2, p< 0,001). Nenhuma das populações de linfócitos analisadas apresentou modificação no 6º mês após a cirurgia. Observou-se aumento significativo da proliferação de linfócitos seis meses após a cirurgia (p= 0,0026). Houve aumento pósoperatório nas concentrações de IFN-, IL-12 e IL-18 produzidas por PBMC após estímulo com PHA, enquanto a IL-2 apresentou uma tendência ao aumento (p= 0,07). As demais citocinas não apresentaram variação significativa. A atividade citotóxica das células NK aumentou seis meses após a cirurgia [17,1 ± 14,7% no pré vs 51,8 ± 11,3% 6 meses pósoperatório, na proporção 40:1 (célula NK:célula alvo); p< 0,001], mostrando recuperação quando se compara aos valores obtidos em indivíduos controle, pareados por idade e sexo, de peso normal [proporção 40:1 (célula NK:célula alvo) de 45,4 ± 7,8%]. Houve aumento de atividade citotóxica em todos os pontos da curva no pós-operatório em cerca de 79% da amostra (22 pacientes). Os resultados obtidos demonstram que a perda de peso induzida por DGJYR aumenta a produção de algumas citocinas relacionadas com a função das células NK e melhora a sua atividade citotóxica. As alterações na função de células NK e do nível de citocinas envolvidas com a atividade destas células podem explicar a propensão ao desenvolvimento de infecções e cânceres associados com a obesidade. Os dados obtidos neste estudo sugerem que a cirurgia bariátrica pode ter impacto positivo sobre estes fatores. / Although obesity is related to immune dysfunction, with a higher incidence of infections and some types of cancer, few studies have evaluated immunological parameters in severely obese patients. Moreover, a limited set of studies have analyzed the effect of weight loss in immunological parameters in severely obese patients. Thus, the objective of this thesis was to evaluate the influence of weight loss induced by Roux en-Y gastric bypass in patients with grade III obesity in immunological parameters. The production of cytokines associated with acquired (IL-2, IL-4, IL-10 and IFN-) and innate (TNF- e IL-6) immune responses from peripheral blood mononuclear cells (PBMCs), the profile of lymphocytes populations and the cytotoxic activity of natural killer cells (NK), besides cytokines related with NK cell cytotoxic function and development (IL-12 e IL-18), were analyzed in 28 non-diabetic and sedentary patients with grade III obesity (20 women and 8 men, 39,9 ± 10,9 years and BMI 49,5 ± 7,1 kg/m2) before and 6 months after RYGB. PBMCs were stimulated with the mitogen phytohemagglutinin (PHA) and cytokines were measure by ELISA. The profile of lymphocytes populations was evaluated by flow cytometry. NK cell cytotoxicity was determined by the lactate dehydrogenase release assay from K562 lysed target cells. The weight loss 6 months after surgery was 35.3±4.5 kg and there was a significant post-surgical decrease in BMI at this point (-12.9±0.9 kg/m2, p<0.001). No significant differences were found in the lymphocytes populations after surgery. It was observed a significant increase in the lymphocytes proliferation six months after surgery (p= 0.0026). There was also a post-surgical increase in the production of IFN-, IL-12 e IL-18 from PBMC stimulated with PHA, while there was a trend towards the increase of the IL-2 production (p=0.07). The other cytokines analyzed were not altered. Cytotoxic activity of NK cells was significantly enhanced 6 months after RYGB [17.1±14.7% before RYGB vs 51.8±11.3% at 6 months after, at effector to target cell (NK cell:K562 cell) ratio 40:1; p<0.001], and it was in the same range when compared to data obtained from controls with normal BMI matched for age and gender (45,4 ± 7,8% at NK cell:K562 cell ratio 40:1). There was a significant post-surgical improvement in all points of the cytotoxic activity curve in almost 79% of the sample (22 patients). In conclusion, the data obtained show that the weight loss induced by RYGB increases the production of cytokines related with NK cell cytotoxic function and improves its activity. The impairment in NK cells cytotoxic activity and cytokines observed in patients with severe obesity may explain their propensity to develop infections and cancer. Our data suggests that the weight loss induced by bariatric surgery can positively impact these factors.

Objetivo: o objetivo deste estudo foi avaliar a prevalência de autoanticorpos e a dosagem da concentração de células Natural Killer (NK) no sangue periférico em pacientes com endometriose. Métodos: Entre dezembro de 2004 e dezembro de 2007 foram avaliadas 155 pacientes submetidas a videolaparoscopia, divididas em um grupo sem endometriose(n=55) e outro com endometriose (n=100). Foi coletada amostra de sangue periférico de todas as pacientes no momento da laparoscopia e nessa amostra foi realizada a quantificação do percentual de células NK em relação aos linfócitos periféricos (por citometria de fluxo), e a determinação dos seguintes auto-anticorpos: anticorpos antinucleares (ANA, por imunofluorescência indireta), anticorpos antitireoglobulina e antiperoxidase (anti-TG e anti-TPO, por eletroquimioluminescência), anticorpos anticardilipina e antifosfatidilserina (aCL e aPS IgG, IgM e IgA, todos por ensaio imunoenzimático). Além da presença de endometriose, essas pacientes também foram avaliadas quanto ao estadiamento, os locais de doença, relações com a fase do ciclo, e a classificação histológica dessa doença. Resultados: as pacientes com endometriose apresentaram percentual de células NK (média DP de 15,3 9,8%) superiores àquelas sem a doença (média DP de 10,6 5,8%), p<0,001. Quanto aos autoanticorpos, as portadoras de endometriose também apresentaram positividade para ANA mais frequentemente (33%) que as pacientes do grupo controle (12,7%), p=0,006. Quanto aos anti-TG, anti-TPO, anti-CL (IgG, IgM e IgA) e aPS ( IgG, IgM e IgA), não houve diferenças estatísticas quanto à sua positividade. As células NK também mostraram-se mais elevadas nas protadoras de endometriose em estádios avançados e naquelas com comprometimento de retossigmóide, grupo no qual encontramos o maior percentual de células NK com concentração média de 19,8 10,3%. Concentrações de células NK 12,5% podem ser usadas como marcadores de endometriose em retossigmóide, com sensibilidade de 73% e especificidade de 65%. Utilizando-se de um modelo estatístico de probabilidades, demonstramos que associação desse marcador (NK 12,5%) com a presença de sintomas como dor e/ou sangramento intestinal durante a menstruação nos possibilitou estimar uma probabilidade de comprometimento de retossigmóide de 60,4%. Conclusões: pacientes com endometriose apresentam maior concentração de células NK periféricas, além de maior prevalência de ANA positivo em relação àquelas sem endometriose. As células NK aumentam nas pacientes com endometriose predominantemente nos estádios avançados, com comprometimento de retossigmóide. Nesse sentido poderiam ser utilizadas como marcadores diagnósticos desse tipo de comprometimento da doença, principalmente se forem avaliadas em conjunto com os sintomas das pacientes / Objectives: The objective of this study was to evaluate the prevalence of autoantibodies and the percentage of natural killer (NK) cells in the peripheral blood of patients with endometriosis. Methods: Between December 2004 and December 2007, 155 patients submitted to videolaparoscopy were evaluated. Patients were divided into two groups: one group of women without endometriosis (n = 55) and another in which all the women had endometriosis (n = 100). Samples of peripheral blood were collected from all the patients at the time of laparoscopy and flow cytometry was used to determine the percentage of NK cells in relation to peripheral blood lymphocytes in these samples. In addition, the following autoantibodies were measured: antinuclear antibodies (ANA) by indirect immunofluorescence, anti-thyroglobulin and anti-thyroid peroxidase antibodies (anti-TG and anti-TPO) by electrochemiluminescence, and anticardiolipin and anti-phosphatidylserine antibodies (aCL and aPS IgG, IgM and IgA), all performed using immunoenzymatic assay. In addition to the presence of endometriosis, these patients were also evaluated with respect to staging, to the sites of the disease, any association with the phase of the menstrual cycle and the histological classification of the disease. Results: The patients with endometriosis had a higher percentage of NK cells (15.3 ± 9.8%; mean ± SD) compared to those without the disease (10.6 ± 5.8%; mean ± SD), (p<0.001). Evaluation of the autoantibodies showed that positivity for ANA was more common in the group of patients with endometriosis (33%) compared to the patients in the control group (12.7%), (p = 0.006). With respect to anti-TG, anti-TPO, aCL (IgG, IgM and IgA) and aPS (IgG, IgM and IgA), no statistically significant differences were found between the groups of patients with or without endometriosis. NK cell concentrations were also found to be higher in patients with advanced stages of endometriosis and in those in whom the rectosigmoid was affected by the disease, this being the group in which the highest percentage of NK cells was found, with mean concentrations of 19.8 ± 10.3%. NK cell concentrations 12.5% may be used as markers of endometriosis of the rectosigmoid, with sensitivity of 73% and specificity of 65%. Using a statistical model of probability, these findings showed that the association of this marker (NK 12.5%) with the presence of symptoms such as pain and/or intestinal bleeding during menstruation permitted an estimation to be made of a likelihood of 60.4% of rectosigmoid endometriosis. Conclusions: Patients with endometriosis have higher percentages of peripheral NK cells, as well as a greater prevalence of positive ANA compared to those without endometriosis. The concentration of peripheral NK cells increases in patients with endometriosis, predominantly in patients with advanced stages of the disease and those in whom the rectosigmoid is affected. Therefore, the concentration of NK cells in peripheral blood could be used as a diagnostic marker of this type of endometriosis, particularly when evaluated together with patients symptoms

Objetivo: o objetivo deste estudo foi avaliar a prevalência de autoanticorpos e a dosagem da concentração de células Natural Killer (NK) no sangue periférico em pacientes com endometriose. Métodos: Entre dezembro de 2004 e dezembro de 2007 foram avaliadas 155 pacientes submetidas a videolaparoscopia, divididas em um grupo sem endometriose(n=55) e outro com endometriose (n=100). Foi coletada amostra de sangue periférico de todas as pacientes no momento da laparoscopia e nessa amostra foi realizada a quantificação do percentual de células NK em relação aos linfócitos periféricos (por citometria de fluxo), e a determinação dos seguintes auto-anticorpos: anticorpos antinucleares (ANA, por imunofluorescência indireta), anticorpos antitireoglobulina e antiperoxidase (anti-TG e anti-TPO, por eletroquimioluminescência), anticorpos anticardilipina e antifosfatidilserina (aCL e aPS IgG, IgM e IgA, todos por ensaio imunoenzimático). Além da presença de endometriose, essas pacientes também foram avaliadas quanto ao estadiamento, os locais de doença, relações com a fase do ciclo, e a classificação histológica dessa doença. Resultados: as pacientes com endometriose apresentaram percentual de células NK (média DP de 15,3 9,8%) superiores àquelas sem a doença (média DP de 10,6 5,8%), p<0,001. Quanto aos autoanticorpos, as portadoras de endometriose também apresentaram positividade para ANA mais frequentemente (33%) que as pacientes do grupo controle (12,7%), p=0,006. Quanto aos anti-TG, anti-TPO, anti-CL (IgG, IgM e IgA) e aPS ( IgG, IgM e IgA), não houve diferenças estatísticas quanto à sua positividade. As células NK também mostraram-se mais elevadas nas protadoras de endometriose em estádios avançados e naquelas com comprometimento de retossigmóide, grupo no qual encontramos o maior percentual de células NK com concentração média de 19,8 10,3%. Concentrações de células NK 12,5% podem ser usadas como marcadores de endometriose em retossigmóide, com sensibilidade de 73% e especificidade de 65%. Utilizando-se de um modelo estatístico de probabilidades, demonstramos que associação desse marcador (NK 12,5%) com a presença de sintomas como dor e/ou sangramento intestinal durante a menstruação nos possibilitou estimar uma probabilidade de comprometimento de retossigmóide de 60,4%. Conclusões: pacientes com endometriose apresentam maior concentração de células NK periféricas, além de maior prevalência de ANA positivo em relação àquelas sem endometriose. As células NK aumentam nas pacientes com endometriose predominantemente nos estádios avançados, com comprometimento de retossigmóide. Nesse sentido poderiam ser utilizadas como marcadores diagnósticos desse tipo de comprometimento da doença, principalmente se forem avaliadas em conjunto com os sintomas das pacientes / Objectives: The objective of this study was to evaluate the prevalence of autoantibodies and the percentage of natural killer (NK) cells in the peripheral blood of patients with endometriosis. Methods: Between December 2004 and December 2007, 155 patients submitted to videolaparoscopy were evaluated. Patients were divided into two groups: one group of women without endometriosis (n = 55) and another in which all the women had endometriosis (n = 100). Samples of peripheral blood were collected from all the patients at the time of laparoscopy and flow cytometry was used to determine the percentage of NK cells in relation to peripheral blood lymphocytes in these samples. In addition, the following autoantibodies were measured: antinuclear antibodies (ANA) by indirect immunofluorescence, anti-thyroglobulin and anti-thyroid peroxidase antibodies (anti-TG and anti-TPO) by electrochemiluminescence, and anticardiolipin and anti-phosphatidylserine antibodies (aCL and aPS IgG, IgM and IgA), all performed using immunoenzymatic assay. In addition to the presence of endometriosis, these patients were also evaluated with respect to staging, to the sites of the disease, any association with the phase of the menstrual cycle and the histological classification of the disease. Results: The patients with endometriosis had a higher percentage of NK cells (15.3 ± 9.8%; mean ± SD) compared to those without the disease (10.6 ± 5.8%; mean ± SD), (p<0.001). Evaluation of the autoantibodies showed that positivity for ANA was more common in the group of patients with endometriosis (33%) compared to the patients in the control group (12.7%), (p = 0.006). With respect to anti-TG, anti-TPO, aCL (IgG, IgM and IgA) and aPS (IgG, IgM and IgA), no statistically significant differences were found between the groups of patients with or without endometriosis. NK cell concentrations were also found to be higher in patients with advanced stages of endometriosis and in those in whom the rectosigmoid was affected by the disease, this being the group in which the highest percentage of NK cells was found, with mean concentrations of 19.8 ± 10.3%. NK cell concentrations 12.5% may be used as markers of endometriosis of the rectosigmoid, with sensitivity of 73% and specificity of 65%. Using a statistical model of probability, these findings showed that the association of this marker (NK 12.5%) with the presence of symptoms such as pain and/or intestinal bleeding during menstruation permitted an estimation to be made of a likelihood of 60.4% of rectosigmoid endometriosis. Conclusions: Patients with endometriosis have higher percentages of peripheral NK cells, as well as a greater prevalence of positive ANA compared to those without endometriosis. The concentration of peripheral NK cells increases in patients with endometriosis, predominantly in patients with advanced stages of the disease and those in whom the rectosigmoid is affected. Therefore, the concentration of NK cells in peripheral blood could be used as a diagnostic marker of this type of endometriosis, particularly when evaluated together with patients symptoms

Lytic effector function of Natural Killer (NK) cells and CD8+ T cells occurs through discrete and regulated cell biological steps triggered by recognition of diseased cells. Recent studies of the NK cell synapse support the idea that dynamic nanoscale rearrangements in cortical filamentous (F)-actin are a critical cell biological checkpoint for lytic granule access to NK cell membrane. Loss of function mutations in the LYST gene, a well-characterised cause of Chediak- Hegashi syndrome (CHS), result in the formation of giant lysosomal organelles including lytic granules. Here, we report a mismatch between the extent of cortical F-actin remodelling and enlarged lytic granules that limits the functionality of LYST- deficient NK cells in a human model of CHS. Using super-resolution stimulated emission depletion (STED) microscopy we found that LYST-deficient NK cells had nanoscale rearrangements in the organisation of cortical actin filaments that were indistinguishable from control cells- despite a 2.5-fold increase in the size of polarised granules. Importantly, treatment of LYST-deficient NK cells with actin depolymerising drugs increased the formation of small secretory domains at the synapse and restored their ability to lyse target cells. These data establish that sub-synaptic F-actin is the major factor limiting the release of enlarged lytic granules from CHS NK cells, and reveal a novel target for therapeutic interventions. While the importance of cortical actin filaments in NK cell cytotoxicity have been established, its persistence at the early stages of T cell synapse formation is disputed. We studied the organisation of cortical actin filaments in synapses formed by primary human T cells using STED microscopy and detected intact cortical actin filaments in key T cell effector subsets including memory CD8+ T cells as early as 5-minutes post-activation. Quantitative analysis revealed that activation specific rearrangements in cortical actin filaments at both CD4+ and CD8+ T cell synapses serve to increase the space between filaments. Additionally, comparison of cytolytic T cells with freshly isolated and IL-2 activated primary NK cells revealed that rapid maturation of the cortical actin meshwork is a specific feature of CD8+ T cell lytic synapses. Using chemical inhibition of actin nucleators, we show that increased cortical relaxation is mediated primarily by the activity of actin related proteins (Arp) -2/3. Taken together, these data establish the critical requirement for dynamic rearrangements in cortical actin filaments at lytic synapses but underscore cell-specific differences in its regulation.

Base teórica: A sepse é uma síndrome heterogênea, definida como disfunção orgânica que ameaça à vida, causada por uma resposta desregulada do hospedeiro à infecção. É um problema de saúde mundial, graças à sua alta prevalência, morbimortalidade associada, além de custos para seu tratamento. As células Natural Killer (NK) fazem parte do sistema imune inato reconhecendo moléculas de HLA de classe I em células alvo, através de seus receptores de membrana killer cell immunoglobulin-like receptors (KIR). A intensidade da resposta à infecção pode variar entre indivíduos, logo pode-se considerar que esta seja determinada por bases genéticas, e estas influenciem na ocorrência de sepse e variabilidade nos desfechos. Objetivos: Avaliar a associação entre os genes KIR e os ligantes HLA em pacientes críticos, comparando pacientes com sepse e controles não sépticos internados na mesma UTI. Métodos: Foi examinado o polimorfismo de 16 genes KIR e seus ligantes HLA em 271 pacientes críticos, caucasóides, sendo 211 pacientes com sepse e 60 controles, pela técnica de PCR-SSO e PCR-SSP, respectivamente. Resultados: Os genes ativadores KIR2DS1 e KIR3DS1 foram mais frequentes nos controles que nos pacientes com sepse (41,23% versus 55,00%, e 36,49% versus 51,67%; p = 0.041 e 0,025, respectivamente). Estes resultados fornecem informação inicial sobre o papel de polimorfismos de KIR na sepse, sugerindo que este possa ser um potencial marcador diagnóstico ou prognóstico da doença. / Background: Sepsis is a heterogeneous syndrome, defined a life-threatening organic dysfunction caused by a dysregulated host response to infection. Sepsis is a global health problem, due to its high prevalence, associated morbidity and mortality, and costs for its treatment. Cells Natural Killer (NK) cells are part of the innate immune system that recognize HLA class I molecules on target cells via membrane receptors called killer cell immunoglobulin-like receptors (KIR). The intensity of the response to an infection may vary among individuals and might be influenced genetic features affecting sepsis occurrence and variability in outcomes. Objectives: To evaluate the association between KIR genes and HLA ligands in critically ill patients, comparing patients with sepsis and without sepsis admitted to the same ICU. Methods: We examined the polymorphism of 16 KIR genes and their HLA ligands in 271 critically ill patients, Caucasians, and 211 patients with sepsis and 60 controls by PCR-SSO and PCR-SSP, respectively. Results: Activating KIR2DS1 and KIR3DS1 genes were more common in controls than in patients with sepsis (41.23% versus 55.00% and 36.49% versus 51.67%, p = 0.041 and 0.025, respectively). These results provide initial information on the role of polymorphism of KIR in sepsis, suggesting that this may be a potential diagnostic or prognostic marker of the disease.

L'inflammation chronique en réponse à l'accumulation de lipoprotéines dans la paroi artérielle est centrale dans le développement de l'athérosclérose. L’immunité innée et adaptée sont impliquées dans ce processus. Les cellules Natural Killer (NK), un des éléments clés de l'immunité innée, ont été identifiées dans les lésions athérosclérotiques humaines et murines. Bien que plusieurs études aient cherché à évaluer le rôle des cellules NK dans des modèles animaux expérimentaux d'athérosclérose, les résultats restent contradictoires, certaines rapportant des effets pro-athérogéniques, d’autres anti-athérogéniques. L'une des principales limites de ces études est le manque de spécificité dans le ciblage de la perte ou du gain de fonction des cellules NK. Nous avons utilisé deux approches génétiques sélectives pour étudier le rôle des cellules NK dans l'athérosclérose: 1) des souris Ncr1iCre/+R26lslDTA/+ dans lesquelles les cellules NK ont été déplétées 2) des souris Noé, dont les cellules NK sont hyper-réactives. Les cellules de la moelle osseuse (BM) de ces souris ont été utilisées pour reconstituer le système hématopoïétique de souris Ldlr -/- irradiées. Après une période de récupération de 4 semaines, les souris ont été mises sous un régime riche en matières grasses (HFD) pendant 8 semaines. L'analyse morphométrique de la taille des lésions ‘athérosclérose dans le sinus aortique et l'aorte thoracique n'a montré aucune différence statistiquement significative entre les 3 groupes. De plus, aucune différence n'a été observée dans la composition de la plaque en termes de teneur en collagène, d'infiltration de macrophages ou de profil immunitaire dans le sang et la rate des souris Ncr1iCreR26lsl-DTA, Noé ou contrôles. Nous avons ensuite étudié la sélectivité de des anticorps anti-asialo-GM1 dans la déplétion des cellules NK, qui avaient été utilisés précédemment pour démontrer le rôle pro-athérogène des cellules NK. Nous avons confirmé les effets non spécifiques de cet anticorps, qui déplète non seulement les cellules NK, mais aussi les lymphocytes NKT et CD8+. Enfin, pour déterminer si l'activation des cellules NK par un stimulus externe pouvait avoir des effets sur l’athérosclérose, nous avons traité les souris chimériques (souris Ldlr -/- irradiées reconstituées soit avec les cellules de moelle contrôle ou déficiente en cellules NK) avec du poly IC (un mimétique viral) pendant 8 semaines de HFD. Nous avons trouvé une réduction significative de la taille des lésions au niveau du sinus aortique et de l'aorte thoracique dans les souris déficientes en cellules NK. Nos résultats, à partir de modèles de souris spécifiques, contredisent les études antérieures et démontrent clairement que chez les souris hypercholestérolémiques, les cellules NK n'ont aucun effet direct sur l'athérosclérose, sauf si elles sont pré-stimulée, comme par exemple dans un contexte d’infection virale ou de présence de tumeurs. / Chronic inflammation is central in the development of atherosclerosis. Both innate and adaptive immunity are involved in this process. Although several studies have evaluated the functions of NK cells in experimental animal models of atherosclerosis, it is not yet clear whether NK cells behave as protective or pro-atherogenic effectors. One of the main caveats of previous studies was the lack of specificity in targeting loss- or gain-of-function of NK cells. Here, we used two selective genetic approaches to investigate the role of NK cells in atherosclerosis: 1) Ncr1iCre/+R26lslDTA/+ mice in which NK cells were depleted, 2) Noé mice in which NK cells are hyperresponsive. No difference in atherosclerotic lesion size was found in Ldlr-/- mice transplanted with bone marrow cells from Ncr1iCreR26Rlsl−DTA, Noé or WT mice. Also, no difference was observed in plaque composition in terms of collagen content, macrophage infiltration or the immune profile in blood and spleen, although Noé chimera had more IFN-y-producing NK cells in comparison with WT mice. Then, we investigated the NK cell selectivity of anti-asialo GM1 anti-serum, which was previously used to conclude to the pro-atherogenicity of NK cells. Anti-asialo GM1 treatment decreased atherosclerosis in both Ldlr-/- mice transplanted with Ncr1iCreR26Rlsl−DTA or WT BM, indicating that its anti-atherogenic effects are unrelated to NK cell depletion. Finally, to determine whether NK cells could contribute to the disease in conditions of pathological NK cell overactivation, we treated irradiated Ldlr-/- mice reconstituted with either WT or Ncr1iCreR26Rlsl−DTA BM with the viral mimic Poly(I:C) and found a significant reduction of plaque size in NK-cell deficient chimeric mice. Our findings, using state-of-the-art mouse models, clearly demonstrate that NK cells have no direct effect on the natural development of hypercholesterolemia-induced atherosclerosis, but may play a role when an additional systemic NK cell overactivation occurs.

[Truncated abstract] Natural killer (NK) cell alloreactivity can be exploited in haploidentical haematopoietic stem cell transplantation (HSCT) to improve graft survival, reduce graft versus host disease and decrease leukaemic relapse. NK cells lyse cells that have reduced expression of class I HLA molecules. In an allogeneic setting, donor NK cells may be activated by the absence of donor (self) class I HLA molecules on recipient cells; the absence of self-epitopes being detected by inhibitory KIR receptors on donor NK cells. The way in which genetic polymorphism of the receptors and ligands affects NK allorecognition of missing self, has not been fully elucidated. HLA-C molecules are divided into two groups, C1 and C2, with KIR2DL1 recognising cells expressing C2 and KIR2DL2 and KIR2DL3 recognising cells expressing C1. Donor NK cells expressing KIR2DL2 or KIR2DL3 can be alloreactive towards a recipient if they lack the C1 epitope and donor NK cells expressing KIR2DL1 can be alloreactive towards a recipient if they lack the C2 epitope. KIR3DL1 recognises the Bw4 epitope present on one-third of HLA-B alleles and certain HLA-A alleles. NK cells from donors expressing KIR3DL1 can be alloreactive towards recipients whose cells lack Bw4. Mismatches of KIR related HLA epitopes does not always results in NK alloreactivity. Therefore it is not possible to reliably predict NK alloreactivity based solely on the donor's HLA type and KIR repertoire and the recipient's HLA type. ... All Bw4-positive HLA-B alleles, with the exception of HLA-B*1301 and B*1302, protected targets from lysis. HLA-A*2402 and HLA-A*3201 unequivocally protected target cells from lysis whereas HLA-A*2501 and HLA-A*2301 provided only weak protection from lysis. KIR3DL1-dependent alloreactive NK clones were identified in donors whose only Bw4 positive allele was HLA-A*2402 but not in donors whose only Bw4 positive HLA allele was HLA-B*1301 or B*1302. Finally this thesis demonstrated that an activating KIR can control NK cell alloreactivity. Donors who are C2 negative and KIR2DS1 positive had NK cells that expressed the activating receptor KIR2DS1 and were capable of lysing cells expressing the C2 epitope. More so, KIR2DS1 dependent NK clones were shown to override inhibitory signals generated by NKG2A interacting with its ligand, HLA-E. The identification of these NK clones has important implications for haploidentical HSCT in that recipient expressing all three NK epitopes, C1, C2 and Bw4 were previously thought to be resistant to alloreactive NK cells controlled by inhibitory receptors. Such patients may be amenable to haploidentical HSCT from C2 negative, KIR2DS1 positive donors. These results will improve the ability to predict NK cell alloreactivity based on a donor's HLA type and KIR repertoire and the recipient?s HLA type.

Multiple myeloma (MM) is an incurable plasma cell malignancy. NK cells have demonstrated anti-MM activity in allogeneic transplants and donor lymphocyte infusions, and may provide a more effective therapy for MM. This work demonstrates cytotoxicity of NK-92 and KHYG-1 against MM cells in chromium release and flow cytometry cytotoxicity assays. At a 10:1 effector to target ratio, the cytotoxicity of NK cell lines against MM cells is 50-90%. Blocking NKp30 significantly reduces the cytotoxicity of NK-92 and KHYG-1, while blocking NKG2D and DNAM-1 only reduces the cytotoxicity of NK-92. Notably, NK-92 and KHYG-1 have shown preferential cytotoxicity against the clonogenic population, killing 89-99% in a methylcellulose cytotoxicity assay. Preliminary results in a xenograft bioluminescent mouse model show that NK-92, but not KHYG-1, reduces the tumor burden detected by bioluminescence imaging and bone marrow engraftment by flow cytometry. Therefore, NK cell lines may offer a more effective therapy for MM.

Multiple myeloma (MM) is an incurable plasma cell malignancy. NK cells have demonstrated anti-MM activity in allogeneic transplants and donor lymphocyte infusions, and may provide a more effective therapy for MM. This work demonstrates cytotoxicity of NK-92 and KHYG-1 against MM cells in chromium release and flow cytometry cytotoxicity assays. At a 10:1 effector to target ratio, the cytotoxicity of NK cell lines against MM cells is 50-90%. Blocking NKp30 significantly reduces the cytotoxicity of NK-92 and KHYG-1, while blocking NKG2D and DNAM-1 only reduces the cytotoxicity of NK-92. Notably, NK-92 and KHYG-1 have shown preferential cytotoxicity against the clonogenic population, killing 89-99% in a methylcellulose cytotoxicity assay. Preliminary results in a xenograft bioluminescent mouse model show that NK-92, but not KHYG-1, reduces the tumor burden detected by bioluminescence imaging and bone marrow engraftment by flow cytometry. Therefore, NK cell lines may offer a more effective therapy for MM.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 185-226). Also available on the Internet.