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A large body of data exists demonstrating the key role of FcRn in extending the half-life of therapeutic antibodies by rescuing them from lysosomal degradation. This led to the widely accepted hypothesis that FcRn binding of an IgG via the CH2-CH3 interface of Fc correlates with IgG half-life. Several studies have demonstrated that in vivo half-life can be modified by changing the binding affinity of IgG to FcRn. These modifications were generated by mutating the coding sequence for the Fc region that resulted in enhanced or reduced FcRn binding at endosomal pH without enhancing binding at neutral pH. In contrast to this, we have observed that the half-lifes of IgG molecules that had showed no target-mediated disposition or off-target binding varies widely, even when they share identical Fc domains. This led us to hypothesize that domains of IgG molecules other than Fc could contribute to the modulation of FcRn binding and affect in vivo half-life. This hypothesis was strengthened by recent publications by other groups showing a correlation between antibody charge and the FcRn affinity and/or in vivo half-life. In this study we explored the role of IgG domains other than the FcRn binding domain in altering the affinity between IgG and FcRn and its relation to the in vivo half-life. Here we describe a surface plasmon resonance (SPR) based assay developed to examine the steady-state binding affinity (KD) of IgG molecules to FcRn. We systematically dissected the contributions of IgG variable domain regions in modulating the affinity between FcRn and IgG. Through analysis of a broad collection of therapeutic antibodies containing more than 100 unique IgG molecules against more than 25 different therapeutic targets we have demonstrated that variable domains and in particular CDRs significantly alter binding affinity to FcRn, by 10 to 80-fold, whereas heavy and light chain isotypes do not. Because CDRs modulate the affinity between IgG and FcRn in our in vitro studies, it is important to understand the role they play in modulation of IgG half-life in vivo as this would have far-reaching implications in the half-life optimization efforts of IgG therapeutics.

Les étapes précoces de l’infection virale sont des évènements critiques dans le déroulement du cycle viral. Notamment, l’entrée virale est la première étape d’interaction entre un virus et une cellule permettant d’initier, de maintenir et de propager l’infection. De ce fait, cette étape constitue une cible majeure de la réponse immunitaire adaptative de l’hôte. C’est ainsi que cette étude bipartite s’est intéressée aux étapes précoces de l’infection du virus de l’hépatite C (HCV). Dans un premier temps, l’obtention de clones de cellules Huh-7.5 n’exprimant plus le récepteur néonatal des immunoglobulines, le FcRn, a permis d’analyser l’implication de ce récepteur dans la neutralisation du HCV par des anticorps neutralisants. Les résultats obtenus nous informent que le récepteur FcRn n’intervient vraisemblablement pas dans la modulation de la neutralisation du HCV. Dans un second temps, nous avons réalisé une étude préliminaire afin d’approfondir les mécanismes régissant l’endocytose du HCV : à savoir, quelles sont les protéines adaptatrices responsables du déclenchement de l’endocytose dépendante de la clathrine et s’il existe une potentielle voie d’entrée alternative pour ce virus. A ces fins, nous avons opté pour une stratégie basée sur la transfection de siRNA, couplée à l’utilisation des pseudoparticules HCVpp qui constituent une approche encore pertinente appliquée à l’étude de l’entrée du HCV. / The early steps during a viral infection are critical events in the course of the viral cycle. Particularly, the viral entry is the first step allowing the interaction between a virus and a cell to initiate, maintain and propagate an infection. Therefore, this very step is a major target for the host adaptive immunity. This bipartite study is focused on the early steps of the infection by the hepatitis C virus (HCV). First of all, generation of Huh-7.5 clones whose expression of the neonatal Fc receptor, FcRn, has been deleted gave us the opportunity to analyze the involvement of this receptor during the neutralization of HCV by neutralizing antibodies. Regarding the results, it appears unlikely that the FcRn modulates the neutralization of HCV. Then we conducted a preliminary study to further explore the mechanisms underlying the endocytosis of HCV: that is, which are the adaptor proteins that trigger the clathrine-mediated endocytosis and if there is another putative entry pathway for the virus. To these ends we opted for a RNAi based strategy coupled to the use of HCV-derived pseudo-particles (HCVpp) that are still useful and relevant tools dedicated to HCV-entry studies.

Le but de cette étude a été d’analyser l’intérêt de l’aérosolthérapie d’anticorps monoclonaux (AcM) dans le traitement du cancer broncho-pulmonaire non à petites cellules (CBNPC) en utilisant le cetuximab, un AcM anti-EGFR. L’expression du récepteur FcRn, essentiel dans la pharmacocinétique et la biodistribution des IgGs thérapeutiques a été étudiée dans le CBNPC. Nos résultats montrent que l’AcM peut résister aux contraintes physiques de la nébulisation. Les données de biodistribution et pharmacocinétique, obtenues dans un modèle animal, indiquent que l’Ac administré par aérosol, s’accumule de façon prolongée au niveau pulmonaire. De plus, les tumeurs chez la souris paraissent sensibles à l’aérosolthérapie avec l’AcM. Par ailleurs, le récepteur FcRn est moins exprimé au niveau transcriptionnel et protéique dans le tissu tumoral que dans le tissu sain adjacent à la tumeur dans le CBNPC. Cette altération de l’expression pourrait être due à l’hyperméthylation du promoteur de ce gène. / The project aims at determining whether aerosoltherapy is well suited for monoclonal antibodies (Mab), in Non-Small Cell Lung Cancer (NSCLC). In addition, exploration of the expression of FcRn, an IgG receptor contributing to increased half-life and biodistribution of Mab, has been studied in NSCLC. Using cetuximab, an anti-EGFR Mab, we showed that Mab resist the physical constraints of nebulization. Biodistribution and pharmacokinetic analyses, using a murine model, revealed that cetuximab is highly and durably accumulated within the lungs and slowly and weakly released into the bloodstream following airways delivery. Moreover, animal tumors seem sensitive to cetuximab aerosoltherapy. Expression analysis of FcRn at both the transcript and protein levels showed that the receptor is downregulated in NSCLC. FcRn alteration of expression in the tumor might be due to hypermethylation of the gene promoter as often found in cancer.

Le FcRn est le récepteur responsable du recyclage des IgG ainsi que de leur transcytose. Ainsi cette protéine a un rôle majeur dans la pharmacocinétique des anticorps thérapeutiques. Nous nous sommes intéressés à différents aspects de l'expression du FcRn. Premièrement nous avons évalué l'influence sur la pharmacocinétique du cétuximab de 2 polymorphismes génétiques influençant l'expression du FcRn. Nous avons montré qu'un Variable Number Tandem Repeat influence la distribution du cétuximab. Nous avons établi que le gène est rarement soumis à des variations de son nombre de copies. Par ailleurs, nous avons montré par une approche de RT-PCR en multiplex l'absence du transcrit FcRn dans les plaquettes humaines. Enfin, l'analyse du niveau de transcrits de FcRn dans un modèle d'activation cellulaire indique qu'il existe une régulation: ce niveau diminue lorsque des monocytes sont différenciés en cellules dendritiques immatures ainsi que lors de l'évolution en cellules dendritiques matures. Les résultats de cette thèse démontrent l'importance de l'étude de l'expression du FcRn dans la variabilité pharmacocinétique des anticorps thérapeutiques. / The FcRn is the receptor responsible for the recycling of IgG and their transcytosis. Thus, this protein has a major role in the pharmacokinetics of therapeutic antibodies. We focused on different aspects of FcRn expression. First, we evaluated the influence on the pharmacokinetics of cetuximab of 2 genetic polymorphisms influencing FcRn expression. We showed that a Variable Number Tandem Repeat influences the distribution of the cetuximab. We determined that the gene is rarely affected by Copy Number Variations. Furthermore, we showed by an RT-PCR approach that the FcRn transcript is absent in human platelets. Finally, the analysis of FcRn transcript level in a model of cellular activation indicates that a regulation occurs : the level decreases when monocytes differenciate into immature dendritic cells as well as during evolution into mature dendritic cells. Results of this thesis demonstrate the importance of the study of FcRn expression in pharmokinetic variability of therapeutic antibodies.

Le FcRn ou récepteur néonatal du Fc des IgG est un récepteur " clé " qui prolonge la demi-vie des IgG et de l’albumine et assure leur biodistribution. Récemment, son rôle s'est étendu à la réponse immunitaire humorale et anti-tumorale. Par ailleurs, certains travaux indiquent que le niveau d’expression du FcRn dans les différents tissus pourrait être à l’origine d’une modulation de ses fonctions. Dans ce contexte, nous avons démontré que l’expression du FcRn était diminuée dans le tissu cancéreux par rapport au tissu sain, chez des patients atteints du cancer du poumon et que cet effet était corrélé à leur pronostic. Afin de comprendre les répercussions de cette diminution sur la tumorigenèse, nous avons mis en place le modèle murin de métastases pulmonaires B16F10, chez les souris FcRn-/-. L'absence de FcRn influence la réponse anti-tumorale, en altérant le nombre de cellules dendritiques et des TCD8+. Pour la première fois, nous avons montré que l'absence du FcRn influençait le développement/maturation et fonctions des cellules NK, fragilisant ainsi encore plus l'immunosurveillance antitumorale. Ces résultats mettent en avant un nouveau rôle du FcRn dans la biologie des cellules NK. Les mécanismes à l’origine de cet effet restent à élucider. / FcRn or neonatal receptor for the Fc portion of IgG is a "key" receptor since it extends the half-life of IgGs and albumin and ensures their biodistribution. Recently, its role has been extended to the humoral and anti-tumor immune. Moreover, some studies indicate that the expression level of FcRn in the different tissues may modulate its functions. In this context, we showed that the expression of FcRn was decreased in lung cancer tissue compared to healthy tissue, in patients with NSLC. This decreased expression is correlated with the prognosis of the patients. In order to understand the impact of the reduced FcRn expression on tumorigenesis, we implemented a murine model of lung metastases, implanting B16F10 cells in FcRn deficient mice. The absence of FcRn influences the anti-tumor response, by altering the number of dendritic cells and TCD8+ cells. We showed for the first time that the lack of FcRn altered the development / maturation and the functional activity of NK cells, thus weakening even more anti-tumor immunosurveillance. These new results on NK highlight a new role of FcRn in the biology of NK cells. The mechanisms underlying this effect need to be elucidated.

Submitted by CRISTIANE DE CASTRO PERNET HARA null (cris_hara@hotmail.com) on 2017-01-19T01:22:00Z No. of bitstreams: 1 tese Cristiane Hara (final).pdf: 5145540 bytes, checksum: 622fefbf8e4e6d0b87d3139952cc8f17 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2017-01-24T13:45:46Z (GMT) No. of bitstreams: 1 hara_ccp_dr_bot.pdf: 5145540 bytes, checksum: 622fefbf8e4e6d0b87d3139952cc8f17 (MD5) / Made available in DSpace on 2017-01-24T13:45:46Z (GMT). No. of bitstreams: 1 hara_ccp_dr_bot.pdf: 5145540 bytes, checksum: 622fefbf8e4e6d0b87d3139952cc8f17 (MD5) Previous issue date: 2016-12-01 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / INTRODUÇÃO - Durante a gravidez, a hiperglicemia materna altera a expressão e a transferência de células imunorregulatórias e de imunoglobulinas e o perfil de citocinas na interface materno-fetal. OBJETIVO – Avaliar, em gestações complicadas por hiperglicemia, a expressão de células NK e o perfil de citocinas no sangue, materno e do cordão umbilical, e na placenta (artigo 1); quantificar a produção de anticorpos e a passagem de IgG total, e respectivas subclasses, via receptor FcRn (artigo 2). MÉTODO - Foram avaliadas 120 gestantes, distribuídas nos grupos: não-diabético (ND; N = 30), hiperglicemia gestacional leve (HGL; N = 30), diabetes mellitus gestacional (DMG; N = 30) e diabetes mellitus tipo 2 (DM2; N = 30). Técnicas de citometria de fluxo foram utilizadas para análise de células e citocinas e, de ELISA, para avaliação das concentrações de IgG total e subclasses. A transferência placentária de anticorpos totais, e respectivas subclasses, foi definida pela relação [(concentrações no sangue de cordão umbilical/sangue materno) x 100]. Na análise estatística foram realizadas análises de variância (ANOVA), seguida pelo teste de Tukey, e de correlação de Pearson, com p < 0,05. RESULTADOS - No sangue materno dos grupos hiperglicêmicos, as células NK CD16+CD56– aumentaram, enquanto que CD16+CD56+ foi menor no grupo DMG. No sangue do cordão do grupo DM2 mostrou uma maior proporção de células CD16+CD56– e CD16–CD56+. As camadas extravilosas da placenta dos grupos DMG e DM2 mostraram maior expressão de CD16+CD56– e independente da camada, a proporção de CD16–CD56+ foi maior em HGL e DMG e menor em DM2. Em relação às citocinas, IL-2 foi menor no sangue materno e IFN-y mais elevados no sangue materno e do cordão do grupo DMG. IL-17 foi mais elevada no sangue materno e do cordão do grupo DM2. A camada extravilosa placentária da HGL mostrou níveis elevados de IL-4, IL-6, IL-10, IL-17, e IFN-γ e baixos níveis de IL-1β e IL-8, enquanto que a camada vilosa placentária continha alta níveis de IL-17 e IFN-γ. O grupo HGL, independentemente da região, apresentaram maiores níveis de IL-8. O grupo DM-2, independentemente da região da placenta mostrou níveis elevados de TNF-α, IL-17, e IFN-γ. O sangue materno de DM-2 e o sangue do cordão umbilical de HGL exibiram uma poporção mais elevada de CD19+ expressas por células B. DM2 mostrou a menor proporção de células CD19+na placenta. A expressão de FcRn aumentou nas células do cordão e placenta de HGL. As células do sangue materno, do sangue do cordão e da placenta de DM2 mostraram menor expressão de FcRn. A maior expressão de FcRn, independente do estado hiperglicêmico foi observada nas células da placenta. Houve menores níveis de IgG no sangue materno em DM2 e maiores no sangue do cordão umbilical de HGL. Os níveis mais elevados de IgG4 foi detectado no sangue de mães hiperglicêmicas. Os níveis mais elevados de IgG3 e IgG4 no sangue do cordão foram detectados em HGL, e os menores de IgG2 e IgG3 níveis em DM2. CONCLUSÃO - A hiperglicemia produz ambiente inflamatório com elevada produção de citocinas, apresentando alterações na expressão de células NK, de FcRn na placenta, na produção e taxa de transferência de IgG. Os níveis celulares que expressam CD16+ e de citocinas no sangue materno, sangue do cordão umbilical e tecido placentário são modificados em gestações complicadas pelo diabetes. A hiperglicemia materna compromete a transferência placentária de IgG1, IgG3 e IgG4. Os resultados sugerem que a hiperglicemia materna, diminui a expressão FcRn em células da placenta e sangue e compromete a produção e transferência de anticorpos maternos para os recém-nascidos. / INTRODUCTION - During pregnancy, the immune response associated with diabetes alters the expression and the transfer of immune cells, including regulatory, immunoglobulins and the profile of cytokines in the maternal-fetal interface. OBJECTIVE - To evaluate the expression of NK cells, and the profile of cytokines in maternal blood, umbilical cord and placenta, quantify the production of antibodies, as well as, the passage of IgG and subclasses, via receptors FcRn in pregnancies complicated by diabetes or hyperglycemia. METHOD - were assessed 120 pregnant women, distributed as non-diabetic (ND; n=30), Mild Gestational Hyperglycemia (MGH; n=30), Gestational Diabetes Mellitus (GDM; n=30) and type 2 Diabetes Mellitus (DM2; N=30). The cells and cytokines were evaluated by flow cytometry. The concentrations of total IgG and subclasses were analyzed by ELISA. Placental transfer of the total and subclasses antibodies were defined in each assay by the ratio [(cord concentrations/maternal concentrations) x 100]. In the statistical analysis we used analysis of variance (ANOVA), followed by Tukey test, and Pearson's linear correlation, with p < 0.05. RESULTS - In the maternal blood from the hyperglycemic groups, the CD16+CD56− NK cells increased, whereas that of CD16+CD56+ decreased in GDM group. Cord blood from DM2 showed a higher proportion of CD16+CD56− and CD16−CD56+. The placental extravillous layer of GDM and DM2 showed an increase of CD16+CD56− cells and, irrespective of region, the proportion of CD16−CD56+ cells was higher in MGH and GDM and lower in DM-2. IL-2 was lower in maternal blood and IFN-����������������������� higher in maternal and cord blood from the GDM group. IL-17 was higher in maternal and cord blood from the DM-2 group. The placental extravillous layer of the MGH showed high levels of IL-4, IL-6, IL-10, IL- 17, and IFN-����������������������� and low levels of IL-1����������������������� and IL-8, whereas the placental villous layer contained high levels of IL-17 and IFN-�����������������������. The GDM group, irrespective of region, showed higher levels of IL-8. The DM-2 group, irrespective of region, placenta showed high levels of TNF-�����������������������, IL-17, and IFN-�����������������������. Maternal blood from DM-2 and cord blood from MGH exhibited a higher proportion of CD19+ expression by B cells. DM-2 showed a lower proportion of CD19+ cells in placenta. FcRn expression increased in cells from cord blood and placenta from MGH. Maternal blood, cord blood and placenta cells from DM-2 showed lower FcRn expression. The highest FcRn expression, irrespective of glycemic status, was observed in placenta cells. Maternal blood IgG levels were lower in DM-2, and cord blood IgG levels were higher in MGH. The highest levels of IgG4 were detected in the blood of hyperglycemic mothers. The highest IgG3 and IgG4 levels in cord blood were detected in MGH, and the lowest IgG2 and IgG3 levels in DM-2. CONCLUSIONS - Hyperglycemia produces inflammatory environment with high production of cytokines, presenting changes in expression of NK cells, FcRn in the placenta, in production and rate of transfer of IgG. The levels of cells expressing CD16+ and cytokines in maternal blood, cord blood, and placental tissue are modified in pregnancies complicated by diabetes. Maternal hyperglycemia compromised placental transfer of IgG1, IgG3 and IgG4. The results suggest that regardless of hyperglycemia degree, it decreases FcRn expression in placenta and blood cells and compromises the production and transfer of antibodies from maternal blood to newborns. / FAPESP: 2012/24212-4 / FAPESP: 2013/13017-9

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