A cross-linking model for the activation of the A cell or immune accessory cell as a function of certain extracellular conditions is developed to determine the valency of the specific factor receptor on the A cell surface. It is found that such a determination can be made based on the FWHM of cross-linking curves which differ by a full order of magnitude between the bivalent receptor case and the monovalent receptor case. This determination can be made provided one can obtain accurate values for the equilibrium constants which characterize the system and provided that activation and IL-1 secretion is a linear function of cross-linking. It is also found that a determination of valence can be made if the equilibrium constants are such that substantial one receptor bridge formation takes place (one antibody molecule bound on both ends by the same receptor). This one-receptor bridge formation only takes place if the receptor is bivalent, and it presents itself in the cross-linking curve in a very distinctive manner. A second network model described as an ecological competition model of steady state lymphocyte populations is presented. This model, known as the symmetrical network theory is analysed numerically by integration of the differential equations and shown to provide a reasonable qualitative picture of the immune system's stable steady states, and offer a glimpse of state switching. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Orientador: Margareth Castro Ozelo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-24T11:38:04Z (GMT). No. of bitstreams: 1 Montalvao_Silmara_M.pdf: 5511908 bytes, checksum: e7e6cf52da6e5f3fb92bce534c8e27ec (MD5) Previous issue date: 2014 / Resumo: Os principais problemas relacionados ao tratamento de pacientes portadores de hemofilia A estão relacionados ao uso terapêutico de fator VIII (FVIII), sendo estes o desenvolvimento de anticorpos neutralizantes anti-FVIII (inibidores), e o desenvolvimento de reações anafiláticas, que são eventos raros, no entanto potencialmente graves. As informações quanto aos isotipos de imunoglobulinas associados a estas duas situações clínicas ainda é limitado. O objetivo deste projeto foi avaliar as características da resposta imune humoral em pacientes com hemofilia A que apresentam inibidor e/ou em condição de reação alérgica ao FVIII. Para estas análises três metodologias foram aplicadas, (1) determinação de anticorpos inibitórios por método de Bethesda-Nijmegen, (2) determinação do isotipo de imunoglobulinas envolvidas subclasses da IgG, IgM e IgE anti-FVIII, por método de ELISA e (3) determinação de citocinas por método multiplex BDTM CBA® (cytometric bead array). Esse projeto foi dividido em três estudos. No primeiro estudo, foram analisadas amostras de 25 pacientes brasileiros com hemofilia A, sendo 44% destes afrodescendentes. Todos os pacientes receberam exclusivamente terapia de reposição com concentrado de FVIII derivado de plasma (pdFVIII) e produtos bypass após o desenvolvimento de inibidor. Cinco pacientes deste grupo foram acompanhados por uma análise longitudinal no período de até três anos. No segundo estudo, 4 pacientes com hemofilia A com inibidor foram avaliados no período em que foram tratados através do protocolo de indução de imunotolerância (ITI) para erradicação do inibidor, também em análise longitudinal. O terceiro consistiu da avaliação de incidência de reação alérgica em pacientes com hemofilia A. Três de 322 pacientes (0,9%) apresentaram reação alérgica após a exposição exclusivamente para pdFVIII durante os últimos quinze anos em nosso centro. Os resultados evidenciaram que a subclasse IgG4 é a principal na modulação em presença de anticorpos inibitórios, enquanto a IgG1 na maior parte das análises estava presente junto a baixos títulos de inibidor.Durante o tratamento de ITI os níveis das interleucinas anti-inflamatórias IL-4 e IL-6 acompanharam o decaimento dos títulos de inibidor e IgG4 nos pacientes que obtiveram sucesso ao tratamento. Além disso, no decorrer do protocolo observou-se uma resposta polarizada para o tipo Th1 como padrão de resposta na conquista da tolerância completa ao FVIII. No contexto da reação alérgica, apenas um dos três pacientes apresentou reatividade da IgE que foi exclusiva ao pdFVIII, sendo negativa no ensaio do IgE anti-rFVIII (anti-fator VIII recombinante), demonstrando que a reatividade não foi específica ao FVIII. O entendimento resposta imune humoral em pacientes com hemofilia A, incluindo a participação da IgG4 e IgG1 no mecanismos envolvendo a presença e erradicação dos inibidores e da IgE na reação alérgica, possibilita ampliar conceitos estabelecidos dos mecanismos envolvidos nessas duas situações. Isso poderá auxiliar no desenvolvimento de novos produtos menos imunogênicos e de novas estratégias para a indução de tolerância ao FVIII, que tenham maior eficiência e melhor custo benefício / Abstract: The main problems related to the treatment of hemophilia A patients are linked to the use of therapeutic factor VIII (FVIII). First, the development of neutralizing antibodies against FVIII (inhibitors), and second development of anaphylactic reactions, which are rare, however potencialy severe. The knowledge about the immunoglobulin isotypes associated with these two clinical situations is still limited.The aim of this project was to evaluate the characteristics of the humoral immune response in patients with hemophilia A who have inhibitors and/or allergic reaction to FVIII. For these analyzes three methods were used (1) inhibitory anti-FVIII antibodies assay by Bethesda-Nijmegen (2) immunoglobulins isotype ELISA assay for anti-FVIII IgG subclasses, IgM and IgE and (3) cytokines assay by BDTM Cytometric bead array (BD CBA®) multiplex method. This project was divided in three studies. In the first study, we analyzed samples from 25 Brazilian hemophilia A patients with 44% African-descents. All patients received exclusively replacement therapy with plasma-derived (pdFVIII) concentrates, and bypassing agents after the development of inhibitors. Five patients from this group were followed for a longitudinal analysis in a period up to three years. In the second study, 4 hemophilia A patients with inhibitor were evaluated also in longitudinal analyses, during the induction of immunotolerance (ITI) treatment for the eradication of the inhibitor. The third study included the evaluation of the incidence of allergic reaction among hemophilia A patients. Three out of 322 patients (0.9%) had allergic reaction after exclusively exposure to pdFVIII during the last fifteen years in our center. The results of these studies demonstrated that IgG4 subclass is the main immunoglobulin involved in the modulation of the inhibitory antibodies, while IgG1 is associated with low-titer inhibitors. During the ITI protocol, the anti- inflammatory interleukins, IL-4 and IL-6 decreased following the IgG4 reduction among the patients that achieved success in the ITI treatment. In addition, during the ITI protocol it was observed a polarized Th1 immune response after the complete success achievement. In the context of allergic reaction, only one out of three patients presented IgE reactivity that was exclusively to pdFVIII, and the assay IgE anti-rFVIII (anti-recombinant FVIII) was negative, confirming that the reativity was not specific to FVIII. The understanding of the humoral immune response in hemophilia A patients, including the role of IgG4 and IgG1 in the mechanisms involving the presence and eradication of inhibitors, and the participation of IgE in allergic reaction, allows to better understand the established concepts of the mechanisms involved in these two situations. This may help the development of less immunogenic new products and new strategies for induction of tolerance to FVIII, with higher efficiency and best value / Mestrado / Clinica Medica / Mestra em Clínica Médica

Introduction: Toxoplasmosis is caused by infection with the protozoan Toxoplasma gondii (T. gondii), an obligate intracellular parasite. T. gondii infects a large portion of the world’s population, but uncommonly causes clinically significant disease. Those that are at greatest risk for more severe disease with toxoplasmosis are the immunologically impaired, fetuses, and newborns. T. gondii infection in immunocompetent patients can present as a self-limiting acute infection, or as an acute systemic disease. There are three main T. gondii genotypes, I, II, and III, with varying geographical prevalence. T. gondii is most commonly acquired via ingestion of infectious oocysts, from the environment, tissue cysts from contaminated food items, vertical transmission, or via organ transplantation from an infected donor. Diagnosis can be made via histological and serologic testing in suspected patients. Seropositive testing should be considered within the clinical context, as IgM antibodies may persist for months to years. IgG antibody avidity patterns further help delineate acute versus chronic infections. Histopathology from tissue biopsy of lymphadenopathy is more commonly pursued to establish diagnosis in immunocompetent patients. Case Report: We present a 37-year-old male who presented to the clinic with persistent bilateral non-tender occipital lymphadenopathy of two months duration. Patient also endorsed an acute fluid filled blister on the penis, recurrent cold sores, and significant fatigue. Review of systems were unremarkable. Patient’s immunizations were up-to-date. Patient is an active military serviceman with history of overseas deployment. Patient reports consuming undercooked meat overseas, as well as game meat preparation while hunting. Similar symptoms were also reported by another fellow veteran. Laboratory studies revealed normal CBC, CMP, and TSH. HIV, gonorrhea, and chlamydia testing were negative. Urology referral found no abnormalities. Aspiration biopsy of the right occipital lymph node demonstrated granulomas and aggregates of histiocytes compatible with reactive hyperplasia. Findings were suggestive of toxoplasmosis and no malignancy was found. Follow up T. gondii serological testing results revealed Ab IgM: 104 AU/ML (reference range 0.0-7.9). Toxoplasma gondii Ab IgG: >400 AU/ML (reference range 0.0-7.1), which were consistent for active infection. Patient was referred to Infectious Disease and supportive therapy was recommended. A three month follow up showed improvement in symptoms. Discussion: Although acute infections with T. gondii in immunocompetent patients typically are self-limiting, more serious systemic infections may occur. A pyrimethamine-containing antibiotic regimen is recommended for treating systemic infections. We propose educating high-risk individuals with appropriate preventive measures, which may be beneficial in preventing Toxoplasmosis.

付記する学位プログラム名: 霊長類学・ワイルドライフサイエンス・リーディング大学院 / 京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第21615号 / 理博第4522号 / 新制||理||1649(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)准教授 Andrew MacIntosh, 教授 古市 剛史, 教授 髙井 正成 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

>Magister Scientiae - MSc / Engineered nanomaterials derived from various bulk materials are being developed in ever larger quantities and with very diverse chemical compositions. The physical and chemical properties of the smaller nanoparticles are very different compared to their larger bulk chemicals. Titanium dioxide nanoparticles (TiO2NPs) are an example of such an engineered nanomaterial. Titanium dioxide nanoparticles are mainly used as a pigment in many applications such as glazes, enamels, plastics, pharmaceuticals, cosmetics, and it is widely used in sunscreens. Human exposure to TiO2NPs can occur both during manufacturing and use.

L'immunité antitumorale induite par les cellules dendritiques intratumorales contribue à l'efficacité de la chimiothérapie à base d'anthracycline dans le cancer. Nous avons identifié un allèle de perte de fonction du gène codant pour le récepteur formyl peptide 1 (FPR1) qui était associé à une faible survie sans métastases et à une survie globale chez les patientes atteintes d'un cancer du sein et colorectal recevant une chimiothérapie adjuvante.Les effets thérapeutiques des anthracyclines ont été abrogés chez les souris Fpr1 (-/-) porteuses de tumeurs en raison d'une immunité antitumorale altérée. Les cellules dendritiques déficientes en Fpr1 ne parvenaient pas à s'approcher des cellules cancéreuses mourantes et, en conséquence, ne pouvaient pas déclencher l'immunité des cellules T antitumorales.Des expériences réalisées dans un dispositif microfluidique ont confirmé que FPR1 et son ligand, l'annexine-1, favorisaient des interactions stables entre les cellules cancéreuses mourantes et les leucocytes humains ou murins.Nous avons également étudié la contribution possible de FPR1 à l'efficacité d'une combinaison de mitoxantrone (MTX) et cyclophosphamide (CTX) pour le traitement du cancer du sein induit par l'hormone.Le cancer du sein induit par une combinaison d'acétate de médroxyprogestérone (MPA) et de 7,12-diméthylbenz [a] anthracène (DMBA) a pu être traité avec succès avec MTX plus CTX dans la mesure où la croissance tumorale était retardée et la survie globale augmentée (par rapport à commandes traitées uniquement avec un véhicule).Toutefois, l'efficacité thérapeutique de la thérapie combinée a été complètement abolie lorsque les récepteurs FPR1 ont été bloqués au moyen de la cyclosporine H (CSH). Des études génétiques futures sur les cancers du sein traités par chimiothérapie néoadjuvante sont nécessaires pour valider ces résultats au niveau clinique.L'ensemble de ces résultats mettent en évidence l'importance de FPR1 dans les réponses immunitaires anti-cancéreux induites par la chimiothérapie. / Antitumor immunity driven by intratumoral dendritic cells contributes to the efficacy of anthracycline-based chemotherapy in cancer. We identified a loss-of-function allele of the gene coding for formyl peptide receptor 1 (FPR1) that was associated with poor metastasis-free and overall survival in breast and colorectal cancer patients receiving adjuvant chemotherapy.The therapeutic effects of anthracyclines were abrogated in tumor-bearing Fpr1(-/-) mice due to impaired antitumor immunity. Fpr1-deficient dendritic cells failed to approach dying cancer cells and, as a result, could not elicit antitumor T cell immunity.Experiments performed in a microfluidic device confirmed that FPR1 and its ligand, annexin-1, promoted stable interactions between dying cancer cells and human or murine leukocytes.We investigated also the possible contribution of FPR1 to the efficacy of a combination of mitoxantrone (MTX) and cyclophosphamide (CTX) for the treatment of hormone-induced breast cancer.Breast cancer induced by a combination of medroxyprogesterone acetate (MPA) and 7,12-Dimethylbenz[a]anthracene (DMBA) could be successfully treated with MTX plus CTX in thus far that tumor growth was retarded and overall survival was extended (as compared to vehicle-only treated controls).However, the therapeutic efficacy of the combination therapy was completely abolished when FPR1 receptors were blocked by means of cyclosporin H (CsH). Future genetic studies on neoadjuvant chemotherapy-treated breast cancers are warranted to validate these findings at the clinical level.Altogether, these results highlight the importance of FPR1 in chemotherapy-induced anticancer immune responses.

The problem of timetabling events is present in various organizations such as schools, hospitals, transportation centers. The purpose of timetabling activities at a university is to ensure that all students attend their required subjects in accordance with the available resources. The set of constraints that must be considered in the design of timetables involves students, teachers and infrastructure. This study shows that acceptable solutions are generated through the application of genetic, memetic and immune system algorithms for the problem of timetabling. The algorithms are applied to real instances of the University of Mumbai in India and their results are comparable with those of a human expert. / Revisión por pares

Whether an individual's state of mind can influence the body's immune system has been studied for several decades. Historical notions of a homeostatic, self-contained, and self-monitored system have been discarded. Studies have explored conditioning effects and cognitive behavioral methods to affect the immune response. This study is based on the assumption that relaxation imagery can be used as an endogenous means to produce specific physiological change in the immune function. Subjects were instructed to make a directional change in the absolute number of peripheral lymphocytes using relaxation imagery.

No description available.

The immune system produces antibodies to recognize and provide protection against infection. The immunoglobulin G (IgG) antibody isotype is present at high serum concentrations and has a longer half-life than other isotypes due to the interaction between its fragment crystallizable (Fc) region with the neonatal Fc receptor (FcRn). This Fc-FcRn interaction, which takes place in many cell types throughout the cardiovascular system, mediates pH-dependent formation of the IgG-FcRn complex and leads to the rescue of IgG from eventual degradation via transport from the low-pH early endosome back to the cell surface for release into serum at pH 7.4. Because this process is the primary determinant of IgG antibody half-life, and because the Fc region is common to all antibodies of the same subtype, the Fc-FcRn system has been a target of numerous antibody design and engineering studies. Indeed, several engineered Fcs have been reported with extended serum half-lives. These novel Fc variants, however, have generally been the result of extensive experimental screening and combinations of individual Fc mutations with known biophysical properties; there are few reports of predominantly structure-based rational Fc design. Notably, simply increasing Fc binding affinity for FcRn at low pH does not appear to be sufficient to achieve the largest increases in half-life (and in some cases, very high affinity results in reduced serum half-life). Most of these engineered Fcs have increased affinity not only at low pH (~6.0), but also at pH 7.4. The longest-lived Fc variant known to date, however, with mutations L309D/Q311H/N434S (“DHS”), has only a modest 5-fold increase in binding affinity compared to wt Fc at low pH, but also exhibits negligible binding to the receptor at pH 7.4 (Lee et al., 2019). This is consistent with previous reports that identify efficient release at physiologic serum pH to be critical to FcRn-mediated half-life extension. Thus, while engineering for affinity at low pH, it is also important to optimize the pH dependence of binding for optimal release at serum pH. The rational design process requires a detailed understanding of the structural and functional details of the interaction, which for a pH-dependent complex like Fc-FcRn must also include an accurate model of the pH-sensing mechanism. Unfortunately, the only publicly available crystal structure of a human Fc-FcRn complex is of the M252Y/S254T/T256E (“YTE”) variant, and was determined only to a relatively low 3.8 Å resolution, leaving the atomic positions of many sidechains, and even regions of the protein backbone, subject to substantial uncertainty. Furthermore, the widely accepted conventional mechanism of pH sensing, involving protonation of key histidine residues on Fc at low pH due to the assumed histidine pKa of 6.5 being within the range of interest (pH 6.0-7.4), is thermodynamically impossible. In this thesis I present an extensive analysis of the Fc-FcRn system, including the generation of all-atom models of human wild-type (wt) and variant complexes and the rat wt complex, and assignment of dominant protonation states at pH 6.0, at which most binding experiments are performed. I validate these models using retrospective molecular dynamics (MD)-based free-energy perturbation (FEP) calculations to compare to a large dataset of wt and mutant binding affinities. During this validation process I identify a residue on FcRn, glutamic acid 133, which adopts a highly unusual configuration in the complex and, due to quantum mechanical electronic polarization effects, is not described well by the fixed-charge molecular mechanics force field used by the FEP calculations, resulting in systematic errors for mutations that affect its hydrogen bonding network. I also identify a new variant, with a V308P mutation in a YTE background (“YTEP”), which induces a previously unreported conformational change that accounts for its high binding affinity compared to YTE and wt. To address the problem of the pH-sensing mechanism, I describe a general method for calculating the pH-sensing free energy of binding for any complex, based on a study of the pH dependence of protein unfolding free energies (Yang and Honig, 1993). The key observation underlying this method is that pH-dependent complex formation must be accompanied by a change in the pKa of one or more titratable groups between the unbound and bound states. Furthermore, the change in binding energy between two pHs can be directly calculated based on those pKas alone. As there are no experimental pKa measurements available for the Fc-FcRn interface residues, I perform these pH-sensing free energy calculations using FEP-based calculated pKas to quantitatively assess which residues at the interface are involved in sensing pH over the physiologically relevant pH range, and present a residue-level model for pH sensing in the Fc-FcRn system. Finally, I present some preliminary work toward the rational design of modified Fc regions with both increased affinity at low pH, and increased pH dependence of binding, using FEP calculations to guide experiment. This type of approach, of computational screening of a large number of different variants, followed by more limited experimental testing of promising leads, has the potential to streamline Fc design efforts and provide further insight into the structural basis of function for the Fc-FcRn system.