Está estabelecido que o processo de glicosilação é essencial para a conformação estrutural e função efetora dos anticorpos. Entretanto, não está completamente claro como diferenças nos carboidratos ligados aos anticorpos podem interferir na sua atividade biológica. Foi previamente descrito que anticorpos IgG1 murinos podem ser divididos em anafiláticos ou não-anafiláticos, de acordo com a sua capacidade de induzir in vivo reação de anafilaxia. Somado a isso, foi verificado que a cadeia de oligossacarídeos N-ligada à molécula de IgG1 é fundamental para a manutenção da sua função efetora. O objetivo do presente trabalho é estudar diferenças estruturais entre os subtipos de IgG murinos que poderiam determinar a sua atividade biológica. O seqüenciamento dos nucleotídeos que codificam os domínios CH2 e CH3 dos dois subtipos de IgG1 permitiu constatar homologia de 100% dessas regiões nas duas moléculas estudadas. Entretanto, ao analisar o padrão de carboidratos N-ligados aos anticorpos IgG1 foi observado maior conteúdo de ácido siálico e fucose na cadeia N-ligada ao anticorpo anafilático em relação à do não-anafilático. Contudo, a remoção de resíduos de ácido siálico por tratamento enzimático do anticorpo IgG1 anafilático resultou na perda da capacidade desta molécula de induzir desgranulação celular in vitro e reação anafilática in vivo, semelhante ao anticorpo IgG1 deglicosilado. Em contraste, a remoção de fucose não afetou a sua função anafilática. A análise por PCR em tempo real da expressão dos genes das enzimas envolvidas no processo de glicosilação das proteínas revelou menor expressão gênica de algumas glicosidases, principalmente as sialiltransferases, no hibridoma e linfócitos B secretores do subtipo IgG1 não-anafilático em relação ao obtido no hibridoma e linfócitos B que secretam a IgG1 anafilática. Além disto, foi observada menor atividade enzimática das sialiltransferases obtidas do hibridoma produtor da IgG1 não-anafilática em relação à do hibridoma que produz a IgG1 anafilática. Em conjunto, estes resultados comprovam que a capacidade de anticorpos IgG1 murinos de induzir anafilaxia é diretamente dependente do conteúdo de ácido siálico presente na cadeia de oligossacarídeos ligada à região Fc do anticorpo, além disso sugerem fortemente que essa maior sialilação observada no tipo anafilático seja resultante da maior expressão gênica destas enzimas e assim da sua atividade enzimática no momento da síntese dos anticorpos. / It is well established that the glycosylation process is essential for the structural conformation and effector function of the antibodies. However, it is quite clear how differences in the carbohydrates attached to the antibodies may interfere with their biological activities. It was previously reported that murine IgG1 antibodies can be divided into anaphylactic or nonanaphylactic according to their ability to induce anaphylaxis. Furthermore, it was demonstrated that the oligosaccharide chain N-linked to the IgG1 is essential for its conformation and biological activity. The objective of this work is to study structural differences between these subtypes of murine IgG1 that could determine their biological activity. The sequencing of the nucleotides encoding the CH2 and CH3 domains of these two subtypes of IgG1 showed 100% of homology in the Fc regions of these molecules. In contrast, the analysis of the carbohydrates N-linked to the IgG1 antibodies demonstrated higher sialic acid and fucose contents in the chain attached to the anaphylactic antibody than in the nonanaphylactic IgG1. However, the removal of sialic acid residues by enzymatic treatment of anaphylactic IgG1 antibody resulted in the abrogation of its ability to induce mast cells degranulation in vitro and anaphylactic reaction in vivo as observed to deglycosylated IgG1 antibody. On the other hand, the removal of fucose did not change the anaphylactic activity. The analysis by real time PCR of the gene expression of enzymes that are involved in the protein glycosylation showed lower gene expression of some glycosyltransferases, mainly sialyltransferases, in the hybridoma and B lymphocytes that produce the non-anaphylactic IgG1 compared to those verified in the hybridoma and B cells producer of the anaphylactic IgG1. Furthermore, it was verified lower enzymatic activity of sialyltransferases purified from the hybridoma producer of the non-anaphylactic IgG1 in relation to the hybridoma producer of the anaphylactic antibody. Together, these results prove that the ability of murine IgG1 to induce anaphylaxis is directly dependent of the sialic acid content in the carbohydrate core attached to the antibody Fc region. It is also strongly suggested that this higher sialylation observed in the anaphylactic IgG1 may be resultant of the higher gene expression and enzymatic activity of some sialyltransferases during the antibody synthesis.

Orientador: Sônia Maria Alves Bueno / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-25T04:00:44Z (GMT). No. of bitstreams: 1 Oliveira_CarlaReis_M.pdf: 2012737 bytes, checksum: 29446d9a4e9ff14301c100dcd3fb82ab (MD5) Previous issue date: 2014 / Resumo: Anticorpos monoclonais (AcM) são imunoglobulinas secretadas por clones de linfócitos B imortalizados obtidos pela tecnologia de hibridomas. Esses clones são cultivados em meios de cultura complexos e, geralmente, liberam baixas concentrações de AcM, dificultando as etapas de purificação. Como a utilização destas proteínas nas áreas terapêutica e analítica requer um alto grau de pureza, diferentes estratégias de purificação vêm sendo desenvolvidas, mas usualmente os anticorpos são purificados por cromatografia de afinidade com proteína A ou G imobilizada, o que representa um elevado custo de produção para processos industriais. No intuito de contribuir para o desenvolvimento de processos de purificação dessas moléculas, estudou-se a purificação do AcM anti-Trypanosoma cruzi isotipo IgG2a em orto-fosfo-serina (OPS) imobilizado em gel de agarose. Contrário ao relatado em literatura, observou-se que o agente quelante apresentou baixa capacidade em imobilizar o íon metalico Ni2+. Além disso, o quelato formado adsorveu a molécula alvo juntamente com impurezas do sobrenadante do meio de cultura. Foi observado também que o OPS se comporta como ligante de troca iônica seletivo para IgG2a em solução tampão Tris-HCl 50 mmol/L pH 7,0, quando imobilizado em gel de agarose ativado com CNBr, porém os ensaios realizados com o ligante imobilizado em gel ativado com bisoxirano demonstraram que a inserção de uma molécula espaçadora reduz a seletividade do adsorvente. O AcM foi recuperado com elevado grau de pureza quando empregado em solução tampão Tris-HCl 50 mmol/L pH 7,0 e dessorção pelo acréscimo de NaCl 1,0 mol/L para promover aumento da força iônica. Os resultados de ensaios dinâmicos revelaram que a eficiência de recuperação do produto foi de 97,3% e a capacidade dinâmica de adsorção foi 0,39 mg de AcM/mL de gel devido. Este trabalho sugere a potencialidade de utilização do ligante OPS para a purificação dos anticorpos anti-Trypanosoma cruzi (IgG2a) / Abstract: Monoclonal antibodies (mAb) are immunoglobulins produced by lynphocyte B clones immortalized by the hibridoma technology. Those clones are cultivated in complex medium and generally produce low levels of mAb, interfering on purificaton steps. Since these antibodies are required for analytical and therapeutical purposes, the need of highly pure antibodies is imperative. Although they are usually purified by chromatografic techniques utilizing immobilized protein A ligands, different strategies for downstream processes have been studied to overcome the high costs of these conventional medias for industrial scale purposes. Aiming to contribute with the development of such processes, the anti-Trypanosoma cruzi mAb (IgG2a isotype) was investigated under chromatographic conditons twards the affinity ligand ortho-phospho-L-serine (OPS) immobilized onto agarose beads. It was observed that despite the fact this ligand has been reported as a chelating agent for the purification of immunoglobulins by IMAC technique, OPS presented low chelating capacity for Ni2+ and the metal complex formed adsorbed the desired protein within culture medium contaminants. It was also observed that under buffering conditions of Tris-HCl 50 mmol/L pH 7.0 OPS behaves as a selective ionic exchanger ligand for IgG2a when immobilized in CNBr activated agarose. On the other hand, when immobilized in bisoxirane activated agarose, OPS has shown that the presence of a spacer arm reduces the selectivity of the adsorbent. The mAb was recuperated in one single step with highly putity degree when operated with adsorption buffer Tris-HCl 50 mmol/L pH 7.0 and elution by increasing the ionic strength with the addition of NaCl 1.0 mol/L. The dynamic tests results showed that the efficiency for product recovery was 97.3% and the dynamic binding capacity was 0.39 mg of mAb/mL swollen agarose. This work suggests the potencial use os OPS ligand affinity for the purification of IgG2a antibodies anti-Trypanosoma cruzi in a single step / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestra em Engenharia Química

Orientador: Sonia Maria Alves Bueno / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-23T20:44:35Z (GMT). No. of bitstreams: 1 Serracchiani_MarcelMafei_M.pdf: 2065791 bytes, checksum: 04a95a39ac0691a669c45efc9e3fc435 (MD5) Previous issue date: 2013 / Resumo: A produção de proteínas recombinantes em plantas transgênicas tem se mostrado uma forma segura, eficiente e barata de obtenção em grande escala de várias proteínas de interesse, tais como vacinas, enzimas industriais, bioativos, biofarmacos e anticorpos e seus fragmentos. Contudo, para que a produção de proteínas recombinantes em plantas se torne viável é necessário o desenvolvimento de um processo de recuperação e separação da molécula alvo que seja eficiente e reprodutivo, pois a produção de biomoléculas em plantas transgênicas, assim como os métodos tradicionais de produção, apresentam componentes indesejáveis que devem ser removidos. Neste trabalho, avaliou-se a purificação de fragmentos Fab de IgG humana adicionados artificialmente (spiking) a extrato protéico de soja não transgênica utilizando-se a técnica de cromatografia de afinidade por íons metálicos imobilizados (IMAC). Estudou-se o efeito dos quelatos IDA-Ni(II) e TREN-Ni(II), dos sistemas tamponantes Tris-HCl, fosfato de sódio e Mes, na presença e na ausência de sal (NaCl) na purificação de fragmentos Fab. Primeiramente foram realizados experimentos cromatográficos com as proteínas nativas do extrato proteico do grão de soja. Dos resultados obtidos, selecionou-se, para o adsorvente agarose-TREN-Ni(II), o sistema tamponante Tris-HCl/Tris-HCl na ausência de NaCl, e para o adsorvente agarose-IDA-Ni(II), selecionou-se o sistema tamponante fosfato de sódio/acetato de sódio contendo NaCl. Estes sistemas tamponantes e adsorventes foram utilizados para purificação dos fragmentos Fab adicionados (spiking) ao extrato proteico de grãos de soja. Em agarose-TREN-Ni(II), os fragmentos Fab foram purificados por cromatografia negativa, obtendo-se 66% dos fragmentos Fab na etapa de flowthrough e lavagem, com um grau de pureza de 91% e fator de purificação de 1,4. Para o adsorvente agarose-IDA-Ni(II), os fragmentos Fab foram purificados por cromatografia tradicional (eluição a pH 5,8), obtendo-se alto grau de pureza do fragmento Fab purificados, com um fator de purificação de 2,5. Este estudo contribuiu para obter conhecimento de base para posterior aplicação da técnica de IMAC na purificação de proteínas recombinantes produzidas em sementes de plantas transgênicas / Abstract: The recombinant proteins production using transgenic plants have been considered a safe, efficient and cheap way of producing on large scale innumerous proteins of interest, such as vaccines, industrial enzymes, bioactives, biopharmaceuticals and antibody and it fragments. However, for the production of recombinant proteins in plants become viable is necessary to develop a process for recovery and separation of the target molecule that is efficient and reproductive, because the production of biomolecules in transgenic plants, as well as traditional production methods, have components reactions which must be removed. In this work, the purification of Fab fragments of human IgG added artificially (spiking) to extract non-transgenic soy protein, using the technique of affinity chromatography on immobilized metal ions (IMAC), was evaluated. The effect of chelating agents IDA-Ni(II) and TREN-Ni(II), and the buffers Tris, sodium phosphate and Mes, in presence and the absent of NaCl, was studied for the Fab purification. First, the chromatographic experiments with the native proteins of soybean extract were performed. From the results obtained, it was selected, for the adsorbent TREN-Ni(II), the buffers system Tris-HCl/Tris-HCl without NaCl, and for the adsorbent IDA-Ni(II), the buffer system sodium phosphate/ sodium acetate with NaCl was selected. These adsorbents and buffer systems were used for purification of Fab fragments added (spiking) to soybean extract proteins. In the agarose adsorbent TREN-Ni (II), Fab fragments were purified by negative chromatography, obtaining 66% of Fab fragments in flowthrough and wash steps with a purity of 91% and purification factor of 1.4. For the adsorbent agarose-IDA-Ni (II), Fab fragments were purified by traditional chromatography (elution at pH 5.8), obtaining a high purity of the purified FAB, with a purification factor of 2.5. This study contributed to obtain knowledge base for application of the technique on the IMAC purification of recombinant proteins produced in transgenic plant seeds / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestre em Engenharia Química

Orientador: Sônia Maria Alves Bueno / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-18T14:28:20Z (GMT). No. of bitstreams: 1 Tsai_YuanMing_M.pdf: 3416327 bytes, checksum: d37231cf12f3af7bab5f7826907d5180 (MD5) Previous issue date: 2011 / Resumo: O presente trabalho teve como objetivo principal, o estudo comparativo dos agentes quelantes CM-Asp e IDA no processo da purificação de IgG humana por cromatografia de afinidade por íon metálico cobalto imobilizado em diferentes sistemas tamponantes na presença e ausência do sal NaCl. Observou-se, para todos os sistemas tamponantes estudados, a adição de sal foi desfavorável em termos de capacidade e seletividade de adsorção de IgG para ambos os agentes quelantes. De acordo com eletroforeses SDS-PAGE e análises nefelométricas, os melhores resultados foram observados em presença de Tris-HCl 25 mmol/L, pH 7,0 para o quelato CM-Asp-Co2+ e fosfato de sódio 25 mmol/L com imidazol 2 mmol/L, pH 7,0 para o quelato IDA-Co2+, obtendo-se fatores de purificação de 8,1 e 4,1 e pureza de 100% e 96%, respectivamente. Foram determinadas as curvas de ruptura por meio de experimentos cromatográficos realizados a diferentes diluições do soro humano, os resultados obtidos evidenciaram uma maior eficiência em termos da capacidade de adsorção nas diluições a 5 e 10 vezes (0,89 e 1,03 mg de proteína total/mL gel) comparado a soro diluído a 2,5 vezes (0,40 mg de proteína total/mL gel), tendo estes demonstrado comportamentos similares ao apresentado em etapa cromatográfica. Os dados de adsorção de IgG foram bem representados pelo modelo de Langmuir-Freundlich, a 25ºC, fornecendo valor de Qm igual a 94,44 mg IgG/mL gel e constante de dissociação de 8,18 x 10-5 mol/L, ordem de grandeza característica para ligantes pseudobioespecíficos / Abstract: In this work, we targeted the comparative study between chelating ligands agarose-CM-Asp and agarose-IDA in the purification of human IgG by Immobilized Metal-ion Affinity Chromatography (IMAC) with immobilized cobalt ion in different buffering systems in the presence or absence of salt. For all buffering systems the addition of salt was unfavorable in terms of adsorption capacity of IgG for both chelating ligands. The best results were obtained in the absence of salt. According to SDS-PAGE electrophoresis and nephelometric analysis, the best conditions observed were Tris-HCl 25 mmol/L, pH 7,0 for the agarose-CM-Asp and sodium phosphate 25 mmol/L with imidazole 2 mmol/L for the agarose-IDA (purification factor of 8,1 and 4,1 and purity of 100% and 96%, respectively). Chromatographic experiments were carried out with different dilutions of human serum to determine the breakthrough curves. The results showed a higher efficiency in terms of adsorption capacity at dilutions of 5 and 10 times (0.89 and 1.03 mg of protein Total / mL gel) compared to serum diluted 2.5 times (0.40 mg total protein / mL gel), these results had similar behaviors as those showed in the chomatografic stage. The adsorption data of IgG at 25ºC were well represented by Langmuir-Freundlich model. Values of Qm equal 94,44 mg of IgG/mL gel and dissociation constant of 8,18 x 10-5 mol/L, characteristic magnitude of pseudospecific ligands / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestre em Engenharia Química

A method is described for the rapid purification of RNA polymerase holoenzyme from small amounts of Escherichia coli cells. Chromatography of a crude extract on a single-stranded DNA agarose column followed by gell filtration chromatography gave 95% pure holoenzyme. The enzyme kinetic characteristics on T7 DNA identical to those of RNA polymerase purified by other more laborious procedures.

A novel method for the immobilization of ribonucleosides to polysaccharides, namely to agarose, is presented, and the immobilized nucleosides are used for the purification of nucleoside-converting enzymes, such as adenosine deaminase, guanase OMP-decarboxylase and xanthine oxidase.

The rapid growth of the biopharmaceutical industry has led to increasing demands on the protein production process. An important aspect is the yield of functional protein, which can be greatly affected by the choice of downstream purification. Purification based on acidic elution can be an issue for pH-sensitive proteins, since dramatic changes in pH can lead to protein aggregation and loss of function. The harsh, acidic elution conditions used in conventional purification of antibodies by Protein A affinity chromatography can thus be problematic. To address this, a calcium-dependent protein domain, called ZCa, has previously been developed for mild purification of antibodies, with elution close to physiological pH. Presented here are engineered variants of ZCa with novel affinity towards other biotherapeutics, which could also benefit from mild purification. Phage display selection, using a ZCa-based library, was applied to isolate promising ZCa-based binders against antigen-binding fragments, tissue plasminogen activator, and granulocyte colony stimulating factor, yet to be characterized. Additionally, three ZCa-based variants from a previous selection, with affinity for single-chain variable fragments (scFvs), have been identified and characterized. In a purification setup, they were shown to elute the scFv protein at neutral pH in a calcium-dependent manner. The reported results demonstrate that novel affinity can be introduced to the ZCa domain, while maintaining the calcium-dependent behavior that enables gentle purification. This offers a strategy for broadening the range of proteins that can be purified under mild conditions, with the benefit of reducing protein aggregation and thus increasing the yield of functional protein. / Den snabba tillväxten inom bioläkemedelsindustrin har lett till ökade krav på processen för proteinproduktion. En viktig aspekt är utbytet av funktionellt protein, där valet av reningsmetod kan ha stor påverkan. Proteinrening med syraeluering kan utgöra ett problem för pH-känsliga proteiner, då stora förändringar i pH kan leda till aggregering och försämrad funktionalitet. Det låga pH som används för eluering i den traditionella reningen av antikroppar med Protein A-baserad affinitetskromatografi kan därmed vara problematiskt. Som ett svar på detta har en kalciumberoende proteindomän, vid namn ZCa, tidigare utvecklats för mild rening av antikroppar med eluering nära fysiologiskt pH. I det här arbetet presenteras nya varianter av ZCa som modifierats för att binda till andra bioläkemedel, vilka också skulle kunna gynnas av mild proteinrening. Fagdisplay av ett ZCa-baserat bibliotek har applicerats för att isolera lovande ZCa-baserade bindare mot antikroppsfragment (Fab), vävnadsplasminogenaktivator och granulocytkolonistimulerande faktor, vilka ännu inte karaktäriserats. Utöver detta identifierades och karaktäriserades tre ZCa-baserade varianter från en tidigare selektion, med affinitet för enkelkedjiga antikroppsfragment (scFv). Då dessa varianter utvärderades för rening visade alla på kalciumberoende eluering av scFv vid neutralt pH. Det här demonstrerar att ny affinitet kan introduceras till ZCa-domänen, där det kalciumberoende beteende som möjliggör mild proteinrening bevaras. Detta erbjuder en strategi för att utöka antalet proteiner som kan renas under milda kalciumberoende förhållanden, vilket med fördel kan minska aggregering och därmed öka utbytet av funktionellt protein.

Three novel, synthetic biarylheterocycles bearing imidazole terminal groups had previously been discovered with high cytotoxicity (IC50 16¿640 nM) against a number of human tumour cell lines. Notably, this biological activity was independent of duplex DNA binding affinity. The compounds were tested in the NCI 60-cell line panel and COMPARE analysis suggests they have a novel mechanism of action, targeting the product of a ¿gene-like sequence¿ of unidentified function. The identity of likely protein targets was explored using a chemical proteomic strategy. Bespoke affinity matrices for chromatography were prepared in which test compounds were attached to a solid support through a biotin tag. A synthetic route to hit compounds containing a biotin moiety in place of one of the imidazole sidechains was developed. Chemosensitivity studies confirmed that the biotinylated compounds retained their activity showing IC50 = 6.25 ¿M in a susceptible cell line, compared with > 100 ¿M for an insensitive cell line. The biotinylated ligands were complexed to a streptavidin-activated affinity column and exposed to cell lysates from the susceptible cell lines. Bound proteins were eluted from the column and separated using SDS-PAGE. Proteins were characterised by MALDI MS and MS/MS and identified using Mascot database searches. Heterogeneous nuclear ribonuclear protein A2/B1 was found to selectively bind to the affinity probes. / Yorkshire Cancer Research, BMSS, School of Life Sciences and the Frank Hudson Memorial Fund

Introduction: Cellular membrane proteins, such as the cytochrome P450 enzyme superfamily (P450), have important roles in the physiology of the cell. P450s are important in metabolising endogenous molecules, as well as metabolising xenobiotic substances for detoxification and excretion. P450s are also implicated in cancer as they can act to ¿negatively¿ de-activate or ¿positively¿ activate cancer therapeutics. Identifying specific P450s that are highly up-regulated at the tumour site could be used to predict drug response and formulate targeted cancer therapy to help diminish systemic side-effects. Methods: Previous enrichment strategies have been unable to isolate the full complement of the P450 superfamily. To develop enrichment procedures for the P450s, a proteomic strategy was developed so that compounds could be screened for their effectiveness as general P450 probes. A standardised work-flow was created, encompassing affinity chromatography, protein concentration/desalting, followed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and high performance liquid chromatography-mass spectrometry (HPLC-MS). A ketoconazole analogue and a 2-EN analogue, with known P450 inhibition, were immobilised on a solid support for comparison to immobilised histamine. Co-factor removal, competitive elution and DTT cleavage of disulfide bonds of probes were utilised to elute bound proteins. Results/Discussion: Inhibitor-beads bound a large range of proteins, including P450¿s, of which some were eluted by co-factor removal, some by competitive elution. Specificity of binding was improved by optimising buffer conditions and solid supports, however non-specific binding was not totally eradicated. All human P450s from spiked samples and 18 P450s from more complex mouse liver samples were recovered using one or more ligands. / Bruker Daltonics

The effects of taste masking are determined by interactions between drug and excipients as well as the microstructures of the particulate drug delivery systems (DDS). Cyclodextrin (CD) is a widely used taste masking agent, to which the relationship between kinetic parameters (Ka and Kd) of a drug and taste masking remains unexplored, which is investigated for the first time in this study. A data base of the kinetic parameters for drug-CD was established by Surface Plasmon Resonance Imaging (SPRi) and High Performance Affinity Chromatography (HPAC). Combined with the electronic tongue, Ka and Kd based models for the taste masking effect of HP-β-CD were successfully established and applied to the prediction of taste masking effects. Paracetamol was used as a model drug for taste masking formulation optimization. As well as drug release the microstructure of solid DDS has considerable influence on drug taste. The microstructure of lipid microspheres and the molecular distribution of drug and excipients in lipid microspheres were investigated by Synchrotron radiation-based micro-computed tomography (SR-μCT) and Synchrotron radiation-based Fourier-transform infrared spectromicroscopy (SR-FTIR), respectively. The results demonstrated that the polymeric formulation components as well as shape and particle size of the drug were the key factors to taste masking of paracetamol by inhibiting bust release thereby reducing the interaction intensity of the bitterness. The FTIR absorption spectra confirmed the deposition and formation of chitosan and gelatin films on the drug microsphere surface by layer-by-layer coating. In conclusion, this research demonstrates the molecular kinetic basis of CD taste-masking as well as microstructural basis of particle systems for bitter taste masking.