Larvas de cisticercos de Taenia crassiceps foram deixadas em repouso em TRIS 9mM pH 7,2 com 1mM EDTA até 180 minutos, os sobrenadantes coletados e processados nos 30, 60, 120 e 180 minutos, dando origem aos antígenos de excreção e secreção (ES 30; ES 60; ES 120 e ES 180). A caracterização do antígeno de excreção e secreção de larvas de Taenia crassiceps foi feito por SDS-PAGE e imunoblot utilizando anticorpos monoclonais (AcMos) anti-T. crassiceps e anti-T. solium e anticorpos humanos. Os resultados mostraram que o rendimento do antígeno ES foi menor nos primeiros 30 minutos (0,4 µg) por larva quando comparado os demais ES (ES 60: 2,4 µg; ES 120: 2,9 µg; ES 180: 2,5 µg). O SDS-PAGE confirmou que no ES 30 há menos proteínas. No imunoblot, o ES 180 mostrou que 6 AcMos (anti-LV-Tcra; anti-ES-Tcra; anti-LV-Tso: A3; anti-T-Tso: B4, B11 e A6) reconheceram apenas as frações 18- e 14-kDa do antígeno ES 180. Os AcMos anti-E-Tso (B8) e anti-LV-Tso (B6) não reconheceram frações do antígeno ES 180. Anticorpos presentes em amostras humanas de pacientes com NC reconheceram as frações protéicas entre 94- a 30-kDa e as de 18- e 14-kDa. Utilizando antígeno ES 180 e amostras de soros de pacientes supostamente saudáveis (GC), foram identificadas proteínas acima de 30-kDa e somente uma amostra reconheceu a de 16- kDa, anômala em relação ao perfil 18- e 14-kDa. As amostras de soro de pacientes com outras parasitoses mostraram reatividade com frações ≥ de 30-kDa do ES 180 e o maior índice de reatividade foi com a proteína 71-KDa. Um total de 77%; 70%; 60% e 70% das amostras de pacientes com toxocaríase, esquistossomose mansônica, hidatidose e Chagas, respectivamente, reconheceram a fração 71-kDa do ES 180. O antígeno ES pode contribuir com futuros estudos abordando a complexa relação parasito hospedeiro na cisticercose e na produção de vacinas para o uso em suínos. / Cysticercus Larvae of Taenia crassiceps were maintained in TRIS 9mM pH 7,2 with 1mM EDTA for 180 minutes; the supernatant was collected and processed at 30; 60; 120 and 180 minutes, originating excretion-secretion antigens (ES 30; ES 60; ES 120 and ES 180). The characterization of the ES antigen was conducted through SDS-PAGE and immunoblot using anti-T. crassiceps and anti-T. solium monoclonal antibodies (AcMos) and human antibodies. The results showed that the production of ES antigen was lower in the first 30 min. (0,4 µg) compared with the others (ES 60: 2,4 µg; ES 120: 2,9 µg; ES 180: 2,5 µg). The SDS-PAGE confirmed that ES 30 presented less protein. By immunoblot,6 AcMos (anti-LV-Tcra; anti-ES-Tcra;anti-LV-Tso: A3; anti-T-Tso: B4, B11 and A6) have recognized only the 18- and 14-kDa fractions of the ES 180. The anti-E-Tso (B8) and the anti-LV-Tso (B6) AcMos did not recognize any fractions. Antibodies from human samples NC recognized the proteins from 94- to 30-kDa and from 18- and 14-kDa. Using serum samples of apparently healthy individuals (GC), the ES 180 antigen showed proteins > 30-kDa and one sample recognized the 16-kDa fraction, anomalous when compared to the 18- and 14-kDa fractions. The serum samples of subjects with other parasitoses showed reactivity ≥ 30-kDa, more frequently with 71-KDa protein. A total of 77%; 70%; 60% and 70% of the samples from subjects presenting toxocariasis, esquistossomose mansonic, hydatidosis and Chagas disease, respectively, recognized the 71-kDa fraction of ES 180. The ES antigen may contribute to further studies on the complex cysticercosis parasite/host relation as well as for the production of vaccines for swine.

Interaktionen zwischen Zellen sowie deren Aktivierung werden im Immunsystem durch verschiedene Zelloberflächenmoleküle reguliert. Inhalt dieser Arbeit war die Untersuchung des kürzlich identifizierten Rezeptor-Ligand-Paares BTLA und HVEM. Zunächst wurden diverse BTLA-spezifische monoklonale Antikörper generiert, mit deren Hilfe erstmals die Lokalisation BTLA-tragender Zellen im Gewebe gezeigt werden konnte. Bei umfassenden Expressionsanalysen fiel auf, dass BTLA auf nahezu allen Leukozytenpopulationen der lymphatischen Organe konstitutiv vorhanden ist, und mit seinem Liganden HVEM koexprimiert wird. Beide Moleküle werden auf verschiedenen Zellpopulationen differenziell exprimiert und aktivierungsabhängig reguliert. Funktionelle Analysen in vitro als auch in vivo ergaben, dass die BTLA-HVEM-Interaktion durch Suppression der T-Zellaktivierung und –proliferation wesentlich zur negativen Regulation der Immunantort beiträgt. Die negative Wirkung von BTLA zeigte sich sowohl bei der Initiation als auch bei bereits fortgeschrittener Aktivierung, unabhängig von der Beteiligung positiver kostimulatorischer Signalwege. Durch Stimulation von T Zellen mit unterschiedlicher BTLA-Oberflächenexpression (verschiedene Subpopulationen oder aus transgenen Mäusen) konnte die strikte Korrelation der negativen Funktion mit der BTLA-Menge auf den Zellen gezeigt werden. Es stellte sich heraus, dass BTLA essentiell für die HVEM-vermittelte Suppression ist und eine wesentliche Beteiligung weiterer HVEM-Interaktionspartner (z.B. CD160) nicht vorliegt. Die Beobachtung von veränderten Lymphozytenpopulationen in BTLA-transgenen Mäusen im Ruhezustand weist zudem auf einen zentralen Beitrag des negativen BTLA-Signals zur Aufrechterhaltung der Homöostase hin. Die ubiquitäre Expression von HVEM und BTLA in Kombination mit der gegenseitigen Modulation beider Interaktionspartner ermöglicht eine flexible Reaktion des Immunsystems auf äußere Einflüsse unter anderem über die negative Regulation durch BTLA / Activation of immune cells is regulated by various cell surface molecules during cell-cell interactions. The aim of this work was the characterization of the recently identified receptor-ligand-pair BTLA and HVEM. Initially, several BTLA-specific monoclonal antibodies were generated. With these antibodies, the localization of BTLA expressing cells in the tissues has been determined for the first time. Further detailed flow cytometric analysis revealed a strong constitutive expression of BTLA on nearly all leukocytes in lymphoid organs. Interestingly, all BTLA-expressing cells co-expressed its ligand HVEM. However, both molecules were differentially expressed on different cell populations in the steady state, but were also regulated in an activation-dependent way. Functional analyses in vitro and in vivo (in an antigen-specific adoptive transfer system) revealed a substantial contribution of the BTLA-HVEM interaction for negative regulation of immune responses by suppressing T cell activation and proliferation. Inhibitory signals of BTLA affect the initial and ongoing activation, irrespective of simultaneous positive signals from other co¬stimulatory pathways. Using wildtype and BTLA-transgenic primary T cells, a strictly linear relationship between the inhibitory function of BTLA and its cell surface levels was observed. The data clearly demonstrate that BTLA expression determined the strength of HVEM-mediated suppression, but also that BTLA is essential for this negative co-stimulation, whereas other HVEM-interaction partners were apparently not involved. Finally, the observed changes in lymphoid cell populations of the BTLA-transgenic mice even in the resting state indicate a prominent role for negative BTLA signals to maintain homeostasis. The ubiquitous expression of HVEM and BTLA together with the reciprocal modulation of both interaction partners supports flexible reaction and regulation of the immune system particularly via the inhibitory function of BTLA.

O projeto de obtenção de huAcMos (Anticorpos Monoclonais Humanizados) tinha como escopo a humanização de anticorpos murinos com potencial terapêutico, inserção das sequências em vetores de expressão e transfecção em células CHO (do inglês, Chinese Hamster Ovary). A expressão do huAcMo Anti-CD18 resultou em baixos níveis da proteína recombinante e inciamos o processo de expressão de isoformas do huAcMo Anti-CD3. As células foram transfectadas com seqüências codificadoras do fragmento FvFc Anti-CD3 e clonadas pelo equipamento ClonePix FL. O fragmento foi caracterizado e demonstrou uma menor afinidade quando comparada com a molécula murina original. Ulizamos o sistema de recombinação homóloga (CHO Flp-In, Invitrogen) para expressão da molécula inteira do huAcMo Anti-CD3. Os clones foram caracterizados e demonstrou, assim como o fragmento FvFc, uma menor afinidade pelo alvo. As diferenças nas propriedades de ligação são freqüentemente encontradas após processos de humanização; dependendo da função efetora esta diminuição de afinidade não é negativa para a molécula. / The humanized antibodies (huMab) project intent to use murine antibodies with therapeutic potencial to obtain more human sequences with maintened specificity. The sequences were inserted in expression vectors and transfected in CHO (Chinese Hamster Ovary) cells. Anti-CD18 huMab expression results in low levels of recombinant protein and lead us to try the expression of Anti-CD3 isoforms. The cells were transfected for the expression of a FvFc antibody fragment and cloned using ClonePix FL equipment. The fragment characterization demonstrate a lower affinity when compared with the murine molecule. We use the homologous recombination system (CHO Flp-In) for the expression of the whole molecule of huMab Anti-CD3; like the FvFc fragment, the whole molecule demonstrate a lower affinity for the target. The differences in the affinity properties are frequently found after humanization process and depending on the expected efector functions is not negatively characterized.

O tratamento de pacientes apresentando doenças inflamatórias imunomediadas com drogas anti-TNF-alfa aumenta o risco da reativação da tuberculose. Isso sugere que tais drogas possam afetar a imunidade celular destes. No entanto, há dados conflitantes sobre se esse tratamento suprime as respostas para o teste tuberculínico (TT) e os ensaios de liberação de interferon-gama (IGRAs) e poucos dados em pacientes com psoríase. O presente estudo avaliou pacientes com psoríase moderada a grave enfocando os efeitos do tratamento com infliximabe em suas respostas imunológicas celulares. Foram avaliadas as respostas imunes celulares de doze pacientes antes e durante o tratamento com infliximabe. As células mononucleares do sangue periférico (PBMC) foram estimuladas com a fito-hemaglutinina (PHA), o superantígeno enterotoxina B (SEB), um lisado de citomegalovírus (CMV), e antígenos de Mycobacterium tuberculosis, e a ativação de linfócitos foi avaliada por ELISPOT para enumerar células secretoras de IFN-y, por ELISA para detecção da secreção de IFN-y, e através da incorporação de[3H] timidina para medir a proliferação. O tratamento com infliximabe não levou à redução de INF-y e da resposta linfoproliferativa nos pacientes. Pelo contrário, aumentou a liberação desta citocina em culturas de PBMC estimulados com PHA e SEB por 12 h. Este efeito foi mais notado no pico do efeito clínico do agente anti-TNF (7 semanas de tratamento) e menos proeminente no seu nadir (logo antes da infusão da próxima dose). Reatividade imunitária ao CMV também não foi significativamente afetada, notando-se leve aumento pelo agente anti-TNF. É de se notar que secreção de IFN-y e resposta proliferativa a Mtb dos dois pacientes TT positivos foram, também, visivelmente aumentadas na semana 7, declinando quando infliximabe atingiu o seu nadir. Os efeitos deletérios do bloqueio do TNF em pacientes com psoríase grave, submetidos ao tratamento com infliximabe parecem ser atenuados, pelo menos parcialmente, por um efeito de aumento na imunidade mediada por células desses pacientes, possivelmente pela diminuição da ação imunossupressora decorrente do excesso de TNF / Treatment of patients with immune-mediated inflammatory diseases with anti-TNF agents increases the risk of tuberculosis reactivation, suggesting that it may affect their cellular immune response. However, there are conflicting data on whether anti-TNF treatment suppresses the responses to tuberculin skin test (TST) and interferon-y release assays and no information regarding psoriasis patients on anti-TNF treatment. The present study evaluated patients with moderate to severe psoriasis focusing on the effects of treatment with infliximab on their cellular immune responses. Cellular immune responses of twelve patients were evaluated before and during infliximab treatment. Peripheral blood mononuclear cells (PBMC) were stimulated with phytohemaglutinin (PHA), the superantigen enterotoxin B (SEB), a cytomegalovirus lysate (CMV), and Mycobacterium tuberculosis antigens, and the lymphocyte activation was evaluated by ELISPOT for enumeration of IFN-y-secreting cells, ELISA for detection of secreted IFN-y, and by [3H]thymidine incorporation for proliferation measurement. Treatment with infliximab does not lead to reduction in the INF-y and lymphoproliferative responses of patients. It rather increased the overnight release of this cytokine in PBMC cultures stimulated with PHA and SEB. This effect was most noted at the peak of the clinical effect of the anti-TNF agent (week 7 of treatment) and less prominent at its nadir (just before infusion of the next dose). Immune reactivity to CMV was also either unaffected or slightly increased by the TNF blocking agent. Of note, the IFN-y and proliferative responses to Mtb from the two TST-responder patients were also remarkably increased at week 7, declining when infliximab reached its nadir. The deleterious consequences of TNF blockade in patients with severe psoriasis undergoing infliximab treatment may be in part attenuated by an enhancing effect on the cell mediated immunity of the patients, possibly due to the abbreviation of the immunosuppressive effect of TNF overexpression

Anticorpos monoclonais (AcMos) para uso terapêutico correspondem a uma área importante na indústria de biofármacos, em especial os AcMos humanos, que apresentam menor probabilidade de elicitar imunogenicidade. O objetivo deste trabalho consistiu em obter AcMos humanos antitetânicos através da separação de linfócitos B produtores de anticorpos específicos utilizando o antígeno ou de plasmablastos. As células foram coletadas de doadores após vacinação e separadas por equipamento de cell sorter. As regiões variáveis dos anticorpos foram amplificadas e clonadas em vetores de expressão, que foram usados para transfectar transitoriamente células HEK293-F. O uso da toxina tetânica conjugada independentemente com dois marcadores, biotina e Alexa Fluor® 647, possibilitou a separação específica de linfócitos B produtores de AcMos antitetânicos, que foram avaliados por ELISA, western blotting e pela inibição da ligação da toxina ao gangliosídio GT1b. O ensaio in vivo mostrou proteção total dos animais contra a toxina tetânica quando três AcMos foram usados em conjunto. / Monoclonal antibodies (mAbs) for therapeutic use correspond to a major area of the biopharmaceutical industry, especially human mAbs that are less prone to elicit immunogenicity. The objective of this work was to obtain anti-tetanus human mAbs through separation of memory B lymphocytes producing specific antibodies stained with the antigen or plasmablasts. Cells were collected from peripheral blood of donors after vaccination and separated through cell sorting. The variable regions of the antibodies were amplified and cloned in expression vectors for transient transfection of HEK293-F cells. The staining with the tetanus toxin labeled independently with two markers, biotin and Alexa Fluor® 647 allowed the separation of specific B lymphocytes producing anti-tetanus mAbs. The antibodies expressed were evaluated by ELISA, western blotting and the inhibition of the binding of the tetanus toxin to the ganglioside GT1b. The in vivo neutralization assay showed that a pool of three different mAbs were able to protect mice against the tetanus toxin.

I established the phage antibody library platform for the identification of specific antibodies. In the first part of my study, I tried to identify antibody against SARS-CoV. Two fragments on the spike protein, which is responsible for inducing viral entry, was chosen as target for the selection of antibody. An antibody was identified which can selectively recognize the SARS-CoV infected cells, but not non-infected cells. Although this antibody was found to retain no neutralizing ability, this specific antibody may have potential to develop for diagnostic purpose. / I utilized the phage system-based cloning method as an attractive approach to screen and identify virus-specific antibodies that can be encoded by the human genome. Once a useful phage clone is identified, unlimited amounts of human monoclonal virus-specific antibodies can be manufactured, and potentially applied clinically for prophylactic and therapeutic uses. The study focuses on two of these new infections, both of which cause severe respiratory disease: SARS and avian influenza. / Identification of specific antibodies, either for diagnostic or therapeutic use, was successfully demonstrated in the two infectious disease models. The phage antibody platform offers a fast and cost-effective method to identify phage antibodies, which can easily be converted to human viral specific monoclonal antibodies for clinical use. / In the 21st century, a number of novel infectious diseases emerged suddenly and spread rapidly, endangering the lives and well-being of people around the world. Severe acute respiratory syndrome (SARS) is a life threatening form of atypical pneumonia that ravaged Hong Kong, Taiwan, China, Canada and many cities in 2003. In the same year, novel avian influenza viruses infected human beings on two continents. Both of these diseases originated in animals and crossed over into the human population. These emerging diseases pose significant public health threats while providing a chilling reminder that another influenza pandemic could occur at any time. Thus, the development of effective therapeutics to control the disease is of paramount importance. Although several vaccines against SARS and avian influenza are available nowadays, the poor clinical performance and frequent mutation of viral strains may limit the practical use and value of the vaccines. Moreover, there are no promising antiviral drugs available for the treatment. Therefore, I aimed to develop an immunotherapy as an alternative treatment option against these diseases. / In the second part of my study, the extracellular domain of matrix protein of avian influenza virus was chosen as target for the selection of antibody. I successfully identified an antibody which can neutralize the avian influenza virus infection. This promising result indicated this antibody has potential to develop for therapeutic use and these antibodies can be easily manufactured in unlimited amounts for clinical application. / Leung, Ka Man. / Adviser: Kwok Pui Fung. / Source: Dissertation Abstracts International, Volume: 71-01, Section: B, page: 0212. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 112-123). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese.

O tratamento de pacientes apresentando doenças inflamatórias imunomediadas com drogas anti-TNF-alfa aumenta o risco da reativação da tuberculose. Isso sugere que tais drogas possam afetar a imunidade celular destes. No entanto, há dados conflitantes sobre se esse tratamento suprime as respostas para o teste tuberculínico (TT) e os ensaios de liberação de interferon-gama (IGRAs) e poucos dados em pacientes com psoríase. O presente estudo avaliou pacientes com psoríase moderada a grave enfocando os efeitos do tratamento com infliximabe em suas respostas imunológicas celulares. Foram avaliadas as respostas imunes celulares de doze pacientes antes e durante o tratamento com infliximabe. As células mononucleares do sangue periférico (PBMC) foram estimuladas com a fito-hemaglutinina (PHA), o superantígeno enterotoxina B (SEB), um lisado de citomegalovírus (CMV), e antígenos de Mycobacterium tuberculosis, e a ativação de linfócitos foi avaliada por ELISPOT para enumerar células secretoras de IFN-y, por ELISA para detecção da secreção de IFN-y, e através da incorporação de[3H] timidina para medir a proliferação. O tratamento com infliximabe não levou à redução de INF-y e da resposta linfoproliferativa nos pacientes. Pelo contrário, aumentou a liberação desta citocina em culturas de PBMC estimulados com PHA e SEB por 12 h. Este efeito foi mais notado no pico do efeito clínico do agente anti-TNF (7 semanas de tratamento) e menos proeminente no seu nadir (logo antes da infusão da próxima dose). Reatividade imunitária ao CMV também não foi significativamente afetada, notando-se leve aumento pelo agente anti-TNF. É de se notar que secreção de IFN-y e resposta proliferativa a Mtb dos dois pacientes TT positivos foram, também, visivelmente aumentadas na semana 7, declinando quando infliximabe atingiu o seu nadir. Os efeitos deletérios do bloqueio do TNF em pacientes com psoríase grave, submetidos ao tratamento com infliximabe parecem ser atenuados, pelo menos parcialmente, por um efeito de aumento na imunidade mediada por células desses pacientes, possivelmente pela diminuição da ação imunossupressora decorrente do excesso de TNF / Treatment of patients with immune-mediated inflammatory diseases with anti-TNF agents increases the risk of tuberculosis reactivation, suggesting that it may affect their cellular immune response. However, there are conflicting data on whether anti-TNF treatment suppresses the responses to tuberculin skin test (TST) and interferon-y release assays and no information regarding psoriasis patients on anti-TNF treatment. The present study evaluated patients with moderate to severe psoriasis focusing on the effects of treatment with infliximab on their cellular immune responses. Cellular immune responses of twelve patients were evaluated before and during infliximab treatment. Peripheral blood mononuclear cells (PBMC) were stimulated with phytohemaglutinin (PHA), the superantigen enterotoxin B (SEB), a cytomegalovirus lysate (CMV), and Mycobacterium tuberculosis antigens, and the lymphocyte activation was evaluated by ELISPOT for enumeration of IFN-y-secreting cells, ELISA for detection of secreted IFN-y, and by [3H]thymidine incorporation for proliferation measurement. Treatment with infliximab does not lead to reduction in the INF-y and lymphoproliferative responses of patients. It rather increased the overnight release of this cytokine in PBMC cultures stimulated with PHA and SEB. This effect was most noted at the peak of the clinical effect of the anti-TNF agent (week 7 of treatment) and less prominent at its nadir (just before infusion of the next dose). Immune reactivity to CMV was also either unaffected or slightly increased by the TNF blocking agent. Of note, the IFN-y and proliferative responses to Mtb from the two TST-responder patients were also remarkably increased at week 7, declining when infliximab reached its nadir. The deleterious consequences of TNF blockade in patients with severe psoriasis undergoing infliximab treatment may be in part attenuated by an enhancing effect on the cell mediated immunity of the patients, possibly due to the abbreviation of the immunosuppressive effect of TNF overexpression

Abstract not available

Im Rahmen dieser Arbeit gelang es, katalytische Antikörper zur Hydrolyse von Benzylphenylcarbamaten sowie zahlreiche monoklonale Antikörper gegen Haptene herzustellen.<br /> <br /> Es wurden verschiedene Hapten-Protein-Konjugate unter Verwendung unterschiedlicher Kopplungsmethoden hergestellt und charakterisiert. Zur Generierung der hydrolytisch aktiven Antikörper wurden Inzuchtmäuse mit KLH-Konjugaten von 4 Übergangszustandsanaloga (ÜZA) immunisiert. Mit Hilfe der Hybridomtechnik wurden verschiedene monoklonale Antikörper gegen diese ÜZA gewonnen. Dabei wurden sowohl verschiedene Immunisierungsschemata als auch verschiedene Inzuchtmausstämme und Fusionstechniken verwendet. Insgesamt wurden 32 monoklonale Antikörper gegen die verwendeten ÜZA selektiert. Diese Antikörper wurden in großen Mengen hergestellt und gereinigt. <br /> <br /> Zum Nachweis der Antikörper-vermittelten Katalyse wurden verschiedene Methoden entwickelt und eingesetzt, darunter immunologische Nachweismethoden mit Anti-Substrat- und Anti-Produkt-Antikörpern und eine photometrische Methode mit Dimethylaminozimtaldehyd. Der Nachweis der hydrolytischen Aktivität gelang mit Hilfe eines Enzymsensors, basierend auf immobilisierter Tyrosinase. Die Antikörper N1-BC1-D11, N1-FA7-C4, N1-FA7-D12 und R3-LG2-F9 hydrolysierten die Benzylphenylcarbamate POCc18, POCc19 und Substanz 27. Der Nachweis der hydrolytischen Aktivität dieser Antikörper gelang auch mit Hilfe der HPLC. <br /> <br /> Der katalytische Antikörper N1-BC1-D11 wurde kinetisch und thermodynamisch untersucht. Es wurde eine Michaelis-Menten-Kinetik mit Km von 210 &#181;M, vmax von 3 mM/min und kcat von 222 min-1 beobachtet. Diese Werte korrelieren mit den Werten der wenigen bekannten Diphenylcarbamat-spaltenden Abzyme. Die Beschleunigungsrate des Antikörpers N1-BC1-D11 betrug 10. Das ÜZA Hei3 hemmte die hydrolytische Aktivität. Dies beweist, dass die Hydrolyse in der Antigenbindungsstelle stattfindet. Weiter wurde zwischen der Antikörperkonzentration und der Umsatzgeschwindigkeit eine lineare Abhängigkeit festgestellt. Die thermodynamische Gleichtgewichtsdissoziationskonstante KD des Abzyms von 2,6 nM zeugt von einer sehr guten Affinität zum ÜZA. <br /> <br /> Hydrolytisch aktiv waren nur Antikörper, die gegen das Übergangszustandsanalogon Hei3 hergestellt worden waren. Es wird vermutet, dass die Hydrolyse der Benzylphenylcarbamate über einen Additions-Eliminierungsmechanismus unter Ausbildung eines tetraedrischen Übergangszustandes verläuft, dessen analoge Verbindung Hei3 ist.<br /> <br /> Im Rahmen der Generierung von Nachweisantikörpern zur Detektion der Substratabnahme bei der Hydrolyse wurden Anti-Diuron-Antikörper hergestellt. Einer der Antikörper (B91-CG5) ist spezifisch für das Herbizid Diuron und hat einen IC50-Wert von 0,19 &#181;g/l und eine untere Nachweisgrenze von 0,04 &#181;g/l. Ein anderer Antikörper (B91-KF5) reagiert kreuz mit einer Palette ähnlicher Herbizide. Mit diesen Antikörpern wurde ein empfindlicher Labortest, der ein Monitoring von Diuron auf Grundlage des durch die Trinkwasserverordnung festgeschriebenen Wertes für Pflanzenschutzmittel von 0,1 &#181;g/l erlaubt, aufgebaut. <br /> <br /> Der Effekt der Anti-Diuron-Antikörper auf die Diuron-inhibierte Photosynthese wurde in vitro und in vivo untersucht. Es wurde nachgewiesen, dass sowohl in isolierten Thylakoiden, als auch in intakten Algen eine Vorinkubation der Anti-Diuron-Antikörper mit Diuron zur Inaktivierung seiner Photosynthese-hemmenden Wirkung führt. Wurde der Elektronentransport in den isolierten Thylakoiden oder in Algen durch Diuron unterbrochen, so führte die Zugabe der Anti-Diuron-Antikörper zur Reaktivierung der Elektronenübertragung. / Attempts to produce catalytic antibodies for hydrolysis of arylcarbamates and arylureas:<br /> The aim of the investigations was to produce antibodies which are able to cleave herbicides resistant to naturally occuring enzymes. Structurally similar carbamate and urea derivatives were chosen for the experiments.<br /> <br /> Phosphonate derivatives were synthesized that mimick possible transition state analogues in structure and charge. Mice were immunized with 4 different derivatives after conjugating them to carrier proteins. 32 hybridomas were established that produce monoclonal antibodies binding to these derivatives. <br /> <br /> The possible cleavage of substrates was determined by immunoassays with monoclonal antibodies against the substrate and the products and with a photometric method based on dimethylaminocinammonaldehyde. The measuring of cleavage products was succeeded by an amperometric method. The enzyme sensor was based on immobilized tyrosinase which oxidizes p-chlorophenol and phenol.<br /> <br /> The antibodies N1-BC1-D11, N1-FA7-C4, N1-FA7-D12 und R3-LG2-F9 hydrolysed the benzylphenylcarbamates POCc18, POCc19 und Substance 27. The hydrolytic activity of these antibodies was also succeeded with HPLC.<br /> <br /> The catalytic antibody N1-BC1-D11 was investigated kinetically and thermodynamically. A Michaelis-Menten-Kinetic was observed (at pH 8.0 exhibited a Km 210 &#181;M, a vmax 3 mM/min and a kcat 222 min-1). These values are in the range of the values obtained for the antibody-catalysed hydrolysis of diphenylcarbamates. The rate enhancement of N1-BC1 was 10. The reaction was completely inhibited by stoichiometric quantities of the transition state analogue Hei3. This is consistent with the affinity of the abzyme to Hei3 of 2.6 nM, determined by BIAcore assay.<br /> <br /> Only antibodies generated against Hei3 showed hydrolytic activity. The hydrolysis of benzylphenylcarbamates presumably occurs via an addition-elimination-Mechanism involving a tetrahedral intermediate. <br /> <br /> In summary, this work presents the first example of antibody-catalysed hydrolysis of benzylphenylcarbamates. <br /> <br /> Monoclonal anti-diuron antibodies were generated that bind to the herbicide diuron with an extremely low equilibrium dissociation constant. A sensitive immunoassay with a low detection limit of 0.2 nM for diuron was established. This is the most sensitive immunological method for detection of diuron known so far.<br /> <br /> These antibodies were also used in vitro and in vivo to prevent diuron-dependent inhibition of photosynthesis or to restore photosynthesis after inhibition. In isolated thylakoids prepared from spinach leaves (Spinacia oleracea L.) the diuron-inhibited Hill reaction was reconstituted immediately following the addition of the monoclonal antibodies. In an in vivo approach the photosynthetic oxygen evolution of the cell wall deficient mutant (cw 15) of the green alga Chlamydomonas reinhardtii Dangeard was monitored. The antibodies prevented the diuron-dependent inhibition of photosynthesis and restored photosynthesis after inhibition. Transgenic plants that synthesize and accumulate these antibodies or antibody fragments and are therefore diuron-resistant can be created.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2010. / Härtill 4 uppsatser.