Les SIgA possèdent la capacité de pouvoir adhérer spécifiquement à la membrane apicale des cellules M présentes au niveau des muqueuses monostratifiées. La capacité des cellules M à transporter les SIgA de la lumière intestinale jusqu'au GALT par un mécanisme de transcytose inverse a également été décrite. J'ai donc souhaité évaluer la capacité des SIgA à transporter efficacement un antigène vaccinal, à travers la barrière épithéliale par l'intermédiaire des cellules M vers les DCs présentes dans le MALT. Le mécanisme exact et notamment la structure moléculaire du récepteur permettant la transcytose inverse des IgA n'a pas été identifiée. Il m’a donc paru intéressant d'améliorer la compréhension des mécanismes physiologiques impliqués dans le transport d'une SIgA de la lumière intestinale jusqu’aux cellules immunitaires sous-muqueuses. Cette étude a permis de démontrer le rôle majeur de deux nouveaux récepteurs présents à la surface des cellules M, la dectine-1 et le siglec-5, dans l'activité physiologique rétrograde des SIgA. Cette étude a permis d'identifier les domaines des SIgA impliqués dans ce mécanisme. J'ai ensuite utilisé les SIgA comme vecteur vaccinal permettant le ciblage des cellules M. Les applications de cette approche à la vaccination par voie orale et nasale sont décrites dans la publication 4 en cours de rédaction. Durant ma thèse, j'ai pu démontrer que la transcytose inverse des SIgA est un mécanisme physiologique dépendant par exemple de récepteurs aux sucres. J'ai pu également démontrer que leur utilisation dans des approches de vaccination muqueuse peuvent être une voie très prometteuse notamment contre le VIH ou d'autres pathogènes muqueux / Secretory IgA (SIgA) are the main effectors of the mucosal immune response. More, SIgA have the capacity to adhere to the apical membrane of M cells present in the intestinal and nasal mucosa. After binding to M cells, SIgA are transported from the intestinal lumen to the GALT by a reverse transcytosis mechanism. In this work, I have assessed the capacity of SIgA to effectively deliver a vaccine antigen through the epithelial barrier via M cells to sub-mucosal dendritic cells (DCs). Precise mechanisms and the IgA-specific receptor(s) for reverse transcytosis have not yet been identified. In this work, I identified the receptors involved in SIgA reverse transcytosis. Both dectin-1 and siglec-5 allow the transport of the Cα1 domain of SIgA by murine an human M cells in vitro and also in vivo. This work is currently undergoing to immunity (publication 1) and should also be patented. Next, I tried to use the reverse transcytosis mechanism mediated by M cells to efficiently deliver an HIV-1 antigen by mucosal routes. We applied results obtained using SIgA as a vaccine vector for M cells targeting. This approach should help to protect antigen in the mucosal environment. Applications of this approach to oral and nasal immunisation are described in the incomplete publication 4. During any PhD, I was able to demonstrate that SIgA reverse transcytosis is a physiological mechanism depending on sugar receptors. I was also able to demonstrate that their use could be a very promising vaccine approach especially for mucosa] diseases or pathogens as HIV

Secretory immunoglobulin-A (S-IgA) in saliva may reflect levels of immune defence at other mucosal sites. Reduced levels of salivary S-IgA have been associated with an increased risk for upper respiratory symptoms (URS) in athletes. Previously, the consumption of a nutrition supplement, bovine colostrum (BC) by distance runners, was shown to significantly increase levels of salivary S-IgA compared to baseline; however the mechanism was not known. The immunomodulatory effect of BC is investigated further in these current studies. Twenty-five swimmers (12 males [M], 13 females [F], age 14-23 years) training at an elite level, 28 lightly-exercising students (9M, 19F, age 18-27 years), and 45 healthy older adults (20M, 20F, age 65-76 years), consumed a supplement of either BC or placebo for ten weeks. Saliva samples were collected at baseline, weekly for four weeks during supplementation and post-supplementation. Blood samples were collected at baseline, monthly during supplementation and post-supplementation. No significant changes were seen in levels of S-IgA in either BC or placebo groups within any of the cohorts. There was a trend towards a significant difference in URS reportage between BC and placebo groups in the swimmers cohort, but not in the students or older adults. There was also a trend towards a difference in the number of swimmers reporting URS. Fewer numbers of swimmers consuming BC reported URS compared the placebo (P=0.062) after consuming BC for four weeks compared to those consuming the placebo. Post-exercise plasma cortisol results were significantly reduced in the BC subgroup compared to the placebo (P=0.004). These results do not support the findings of previous intervention studies investigating the immunomodulatory effect of BC in athletes. However the reduced reportage of URS, among swimmers consuming the BC supplement, suggested there was some benefit to their health. A possible explanation is that BC has impacted on non-infectious causes of URS. Growth factors present in BC may enhance intestinal repair which could be advantageous to athletes recovering from bouts of prolonged intensive exercise. The effect of gastrointestinal disturbances on local and systemic immunity may be minimised which benefits immune protection. However an inconsistent effect of BC supplementation on immune protection in athletes means further research is still required. In these studies there was no benefit to immune protection in the student or older adult cohort. Further investigation into the safety of BC for all population groups is still required.

Atopic allergy is the most common chronic disease among children in the developed world. This high prevalence could be associated with low microbial exposure. The early gut microbiota appears to be important for immune maturation. Immunomodulatory components in human milk might differ between mothers and could therefore explain the contradictory results seen regarding breastfeeding and allergy development. The aim of this thesis was to investigate whether early colonization with certain gut microbiota species influences childhood immune responses and allergy development up to age five. Also, as human milk oligosaccharides (HMOs) might stimulate the growth of certain gut microbiota species, the consumption of neutral colostrum HMOs was investigated for their role in allergy development up to 18 months. The concentrations of neutral colostrum HMOs varied considerably between women; however this variation could not be explained by their allergic status. Neither was the consumption of neutral colostrum HMOs related to allergy development in their children up to 18 months. Infants who harboured lactobacilli group I and Bifidobacterium adolescentis one week after birth developed allergic disease less frequently during their first five years than infants who did not harbour these bacteria at the same time. Also, colonization with several Bifidobacterium species was associated with higher levels of house dust endotoxin and larger family size. The early Bifidobacterium flora influenced levels of salivary secretory IgA at six and 12 months but not during later childhood. Moreover, the intensity of early Bacteroides fragilis colonization was inversely associated with spontaneous Toll-like receptor 4 mRNA expression in peripheral blood cells collected 12 months after birth. In conclusion, these results indicate that the early infant gut microbiota influences systemic and mucosal immune maturation during infancy, and that it might be altered in infants developing allergic disease.

Previous studies have demonstrated that chitosan and its derivative, N-trimethyl chitosan chloride (TMC) are effective and safe absorption enhancers to improve mucosal delivery of macromolecular drugs including vaccines. Furthermore, chitosan and TMC can easily form microparticles and nanoparticles, which have the ability to encapsulate large amounts of antigens. Emzaloid™ technology has proven in the past to be an effective delivery system for numerous drugs. Emzaloids can entrap, transport and deliver large amounts of drugs including vaccines. In this study, the ability of chitosan microparticles and nanoparticles, TMC microparticles as well as micrometer and nanometer range Emzaloids to enhance both the systemic and mucosal (local) immune response against diphtheria toxoid (DT) after nasal administration in mice was investigated. The above mentioned formulations were prepared and characterised according to size and morphology. DT was then associated to the chitosan microparticles and nanoparticles as well as TMC microparticles to determine the antigen loading and release. It was found that the loading efficacy of the formulations was 88.9 %, 27.74 % and 63.1 % respectively, and the loading capacity of the formulations was 25.7 %, 8.03 % and 18.3 %. DT loaded and unloaded (empty) chitosan microparticles and nanoparticles, TMC microparticles, micrometer and nanometer range Emzaloids as well as DT in phosphate buffered saline (PBS) were administered nasally to mice. Mice were also vaccinated subcutaneous with DT associated to alum as a positive control. All mice were vaccinated on three consecutive days in week 1 and boosted in week 3. Sera was analysed for anti- DT IgG and nasal lavages were analysed for anti-DT IgA using an enzyme linked imrnunosorbent assay (ELISA). In the study conducted to determine the systemic (IgG) and local (IgA) immune responses it was seen that DT associated to all the experimental formulations produced a systemic immune response. The said formulations produced a significantly higher systemic immune response when compared to the formulation of DT in PBS. Furthermore, the mice vaccinated with DT associated to the TMC formulations showed a much higher systemic immune response than the mice that were vaccinated subcutaneously with DT associated to alum, whereas the other formulations produced systemic immune responses that were comparable to that of DT associated to alum. It was also found that DT associated to the experimental formulations produced a local immune response, however only DT associated to TMC microparticles produced a consistent local immune response. It can be concluded from the in vivo experiments that the TMC formulations, moreover, the TMC microparticles is the most effective and promising formulation for the nasal delivery of vaccines. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2005.

Previous studies have demonstrated that chitosan and its derivative, N-trimethyl chitosan chloride (TMC) are effective and safe absorption enhancers to improve mucosal delivery of macromolecular drugs including vaccines. Furthermore, chitosan and TMC can easily form microparticles and nanoparticles, which have the ability to encapsulate large amounts of antigens. Emzaloid™ technology has proven in the past to be an effective delivery system for numerous drugs. Emzaloids can entrap, transport and deliver large amounts of drugs including vaccines. In this study, the ability of chitosan microparticles and nanoparticles, TMC microparticles as well as micrometer and nanometer range Emzaloids to enhance both the systemic and mucosal (local) immune response against diphtheria toxoid (DT) after nasal administration in mice was investigated. The above mentioned formulations were prepared and characterised according to size and morphology. DT was then associated to the chitosan microparticles and nanoparticles as well as TMC microparticles to determine the antigen loading and release. It was found that the loading efficacy of the formulations was 88.9 %, 27.74 % and 63.1 % respectively, and the loading capacity of the formulations was 25.7 %, 8.03 % and 18.3 %. DT loaded and unloaded (empty) chitosan microparticles and nanoparticles, TMC microparticles, micrometer and nanometer range Emzaloids as well as DT in phosphate buffered saline (PBS) were administered nasally to mice. Mice were also vaccinated subcutaneous with DT associated to alum as a positive control. All mice were vaccinated on three consecutive days in week 1 and boosted in week 3. Sera was analysed for anti- DT IgG and nasal lavages were analysed for anti-DT IgA using an enzyme linked imrnunosorbent assay (ELISA). In the study conducted to determine the systemic (IgG) and local (IgA) immune responses it was seen that DT associated to all the experimental formulations produced a systemic immune response. The said formulations produced a significantly higher systemic immune response when compared to the formulation of DT in PBS. Furthermore, the mice vaccinated with DT associated to the TMC formulations showed a much higher systemic immune response than the mice that were vaccinated subcutaneously with DT associated to alum, whereas the other formulations produced systemic immune responses that were comparable to that of DT associated to alum. It was also found that DT associated to the experimental formulations produced a local immune response, however only DT associated to TMC microparticles produced a consistent local immune response. It can be concluded from the in vivo experiments that the TMC formulations, moreover, the TMC microparticles is the most effective and promising formulation for the nasal delivery of vaccines. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2005.

Hantaviruses are the causative agents of hemorrhagic fever with renal syndrome (HFRS) in Eurasia, and of hantavirus cardiopulmonary syndrome (HCPS) in the Americas. Transmission to humans usually occurs by inhalation of aerosolized virus-contaminated rodent excreta. To date, human-to-human transmission has only been described for the Andes hantavirus. The mode of transmission of Andes hantavirus is not yet known, but transmission through saliva has been suggested. In Sweden, we have one hantavirus that is pathogenic to humans, Puumala virus (PUUV), which is endemic in Central and Northern Europe. It induces a relatively mild form of HFRS, also called nephropathia epidemica (NE). The rodent reservoir is the bank vole (Myodes glareolus). The mechanism behind the pathogenesis of hantavirus is complex and probably involves both virus-mediated and host-mediated mechanisms. The aim of this project was to investigate the transmission mechanisms and pathogenesis of hantavirus disease in humans. In our first study, we described the largest outbreak of PUUV so far in Sweden. We investigated factors that might be important for causing the outbreak, and suggested that a peak in the bank vole population together with concurrent extreme weather conditions most probably contributed to the outbreak. Our next studies concentrated on human-to-human transmission of hantaviruses. We found PUUV RNA in saliva from PUUV-infected patients, suggesting that there is PUUV in the saliva of infected humans, although no person-to person transmission appears to occur with PUUV.  In the studies that followed, we showed that human saliva and human salivary components could inhibit hantavirus replication. We also found PUUV-specific IgA in the saliva of PUUV-infected patients, which might prevent person-to-person transmission of the virus.  In the final study, we focused on the pathogenesis of NE. One hundred five patients were included in a prospective study.  They were divided into a group with mild disease and a group with moderate or severe disease. We found that the immune response had a dual role in disease development. It was partly responsible for development of severe disease, with significantly higher amounts of neutrophils in severely ill patients, but it was also protective against severe disease, because patients with mild disease had higher levels of PUUV-specific IgG. In conclusion, a peak in the bank vole population in combination with extreme weather will increase the risk of human infection, PUUV RNA is present in saliva, PUUV-specific IgA and salivary components inhibit person-to-person transmission of PUUV, and the immune response is important for the pathogenesis of PUUV and the severity of the disease. / Hantavirus är en grupp av virus som finns hos gnagare som bär på viruset utan att själva bli märkbart sjuka. Varje hantavirus har anpassat sig till sin egen art av gnagare som de infekterar (kallas virusets reservoar). Hantaviruset kan överföras till människor från gnagare och kallas då för en zoonos eftersom detsprids från djur till människa. I människa orsakar hantavirus blödarfeber med njurpåverkan i Eurasien och blödarfeber med med hjärt och lungpåverkan i Nord- och Sydamerika. I Sverige har vi bara ett hantavirus som är sjukdomsframkallande hos människor, Puumala-viruset som även finns i delar av övriga Europa. Det framkallar en relativt mild form av blödarfeber, som kallas sorkfeber eller Nephropathia epidemica. Puumala-virusets reservoar är skogssorken (Myodes glareolus). Människor smittas oftast av hantavirus när de andas in infekterat damm som innehåller utsöndringar (avföring, urin eller saliv) från gnagare som har torkat in och sedan blivit luftburet. Vad man vet hittills så finns det bara ett hantavirus som smittar från person till person, för övriga hantavirus är människan en ”dead end”. Det virus som kan smitta från person till person heter Andes hantavirus och finns i Sydamerika. Andes hantavirus har en mus som reservoar från vilken människor kan smittas, sedan har smittan i vissa fall förts vidare från människa till människa, som tur är har dessa utbrott gått att stoppa. Fastän utbrotten har varit små har många personer dött, eftersom dödligheten är så hög, ungefär 30-40% av de diagnostiserade fallen dör. Hur Andes hantavirus överförs från människa till människa är inte känt men överföring genom saliv har föreslagits. Hur viruset ger upphov till sjukdom hos människa är inte klarlagt. Studier talar för att mekanismen bakom sjukdomsutvecklingen (den så kallade patogenesen) hos hantavirusorsakade blödarfebrar är komplex. Sannolikt beror patogenesen både på egenskaper hos viruset och värden d.v.s. människan som är smittad av viruset. Vårt mål med detta projekt var att undersöka vad som hindrar överföring av Puumala hantavirus från människa till människa och att undersöka hur virusinfektionen påverkar sjukdomsutvecklingen hos människan. I vår första studie beskrev vi det största utbrottet av sorkfeber hittills i Sverige och vi undersökte faktorer som kan ha orsakat utbrottet. Vi föreslog att en topp i skogssorkpopulationen samtidigt med extremt varmt väder troligen bidrog till utbrottet. Utbrottet skedde i december och det extremt varma vädret medförde att snön smälte bort. Sorkarna bor vanligtvis under snön på vintern, vi tror att frånvaro av snötäcke fick sorkarna att söka sig till byggnader för att söka skydd och där kom i kontakt med människor. Våra efterföljande studier fokuserade på överföring av hantavirus från människa till människa. Vi hittade Puumala-virusets arvsmassa (RNA) i saliv från sorkfeberpatienter, vilket tyder på att det finns Puumala-virus i saliven hos infekterade människor, även om ingen överföring från person till person verkar inträffa. I efterföljande studier visade vi att mänsklig saliv och mänskliga salivkomponenter minskar hantavirus smittsamhet. Vi fann också Puumala-virusspecifika IgA-antikroppar i saliven från sorkfeberpatienter, vilket kan förhindra överföring från person till person. I den sista studien fokuserade vi på patogenesen hos människor efter hantavirusinfektion. 105 patienter ingick i en prospektiv studie och delades in i en grupp med mild sjukdom och en grupp med måttlig/svår sjukdom. Vi hittade en dubbel roll hos immunsvaret för sjukdomsutvecklingen. Immunsvaret var delvis ansvarig för utveckling av svår sjukdom med betydligt högre mängd neutrofiler hos svårt sjuka patienter, men det var också skyddande mot allvarlig sjukdom, eftersom patienter med en mild sjukdom hade högre nivåer av Puumalavirusspecifika IgG-antikroppar. Detta talar för att behandling med IgG-antikroppar specifikt riktade mot hantavirus skulle kunna vara effektiv hos hantavirusinfekterade patienter. Sammanfattningsvis; en topp i skogssorkspopulationen i kombination med extremt väder ökar risken för infektion hos människor; Puumala-virus arvsmassa (RNA) finns i saliv; Puumala-virusspecifika IgA-antikroppar och salivkomponenter hämmar överföring av Puumalavirus från person till person; immunsvaret är viktigt för Puumala-virus patogenes och sjukdomens svårighetsgrad.

This study aimed to evaluate the clinical efficacy and systemic/mucosal antibody response changes after sublingual immunotherapy (SLIT) using Dermatophagoides pteronyssinus (Dpt) allergens with or without bacterial extracts in mite-allergic children. One-hundred and two patients presenting allergic rhinitis with or without asthma were selected for a randomized double-blind, placebo-controlled trial and distributed into three groups: DPT (Dpt allergen extract, n=34), DPT+MRB (Dpt allergen plus mixed respiratory bacterial extracts, n=36), and Placebo (n=32). Clinical evaluation and immunological analyses were carried out before and after 12 and 18 months of treatment, including rhinitis/asthma symptom and medication scores, skin prick test (SPT) to Dpt extract, and measurements of Dpt, Der p 1, Der p 2 specific IgE, IgG4, and IgG1 in serum and specific IgA in saliva and nasal lavage fluid. Clinical results showed a significant decline in rhinitis/asthma symptom scores in all groups, but medication use decreased only in DPT group after 12 months. SPT results showed no significant changes and SLIT was generally safe, with no severe systemic reactions. SLIT using Dpt allergen alone induced increased serum IgG4 levels to Dpt, Der p 1 and Der p 2, and increased serum IgG1 and salivary IgA levels to Dpt and Der p 1. SLIT using DPT+MRB was able to decrease IgE levels to Der p 2, to increase salivary IgA levels to Der p 1, but had no changes on specific IgG4 and IgG1 levels. In conclusion, clinical improvement was observed both in the SLIT group and the control, but only active SLIT was able to modulate the mucosal/systemic antibody responses. These findings support the role of specific serum IgG4 and IgG1, in addition to salivary IgA, as probable blocking antibodies or biomarkers of tolerance that may be useful for monitoring the allergen specific immunotherapy. / Este estudo teve como objetivo avaliar a eficácia clínica e alterações da resposta de anticorpos sistêmicos e de mucosa após a imunoterapia sublingual (SLIT), utilizando alérgenos de Dermatophagoides pteronyssinus (Dpt), com ou sem extratos bacterianos em crianças alérgicas a ácaros. Cento e dois pacientes com rinite alérgica com ou sem asma foram selecionados para um estudo randomizado duplocego, controlado por placebo e distribuídos em três grupos: DPT (extrato alergênico de Dpt, n=34), DPT+MRB (extrato alergênico de Dpt associado com extrato de bactérias mistas do trato respiratório, n=36), e Placebo (n=32). Avaliação clínica e análises imunológicas foram realizadas antes do tratamento e após 12 e 18 meses, incluindo a pontuação de escores de sintomas e medicamentos de rinite/asma, teste cutâneo (SPT) ao extrato Dpt, e medidas de anticorpos específicos IgE, IgG4 e IgG1 para Dpt, Der p 1, Der p 2 no soro e IgA específicos na saliva e no lavado nasal. Os resultados clínicos mostraram uma redução significativa nos escores de sintomas de rinite/asma em todos os grupos, mas o uso de medicamentos diminuiu apenas no grupo DPT após 12 meses. Resultados de SPT não mostraram mudanças significativas e SLIT foi geralmente segura, sem reação sistêmica grave. SLIT usando somente alérgeno Dpt induziu aumento dos níveis de IgG4 para Dpt, Der p 1 e Der p 2 no soro, e aumentou os níveis de IgG1 no soro e salivares de IgA para Dpt e Der p 1. SLIT usando DPT+MRB foi capaz de diminuir os níveis de IgE para Der p 2, aumentar os níveis salivares de IgA para Der p 1, mas não tiveram alterações nos níveis de anticorpos específicos de IgG4 e IgG1. Em conclusão, foi observado melhora clínica tanto no grupo da SLIT como do controle, porém somente na SLIT com alérgeno foi capaz de modular as respostas de anticorpos sistêmicos e de mucosa. Estes achados reforçam o papel de anticorpos IgG4 e IgG1 séricos específicos, além de IgA salivar, como prováveis anticorpos bloqueadores ou biomarcadores de tolerância que podem ser úteis para monitoramento da imunoterapia alérgeno-específica. / Doutor em Imunologia e Parasitologia Aplicadas

No description available.

Background: IgA vasculitis/Henoch-Schoenlein purpura (IgAV/HSP) is a systemic small vessel vasculitis of unknown pathogenesis predominantly affecting children. While skin, GI tract, joints, and kidneys are frequently affected and considered, central nervous system (CNS) involvement of this disease is underestimated. Methods: We provide a case report and systematically review the literature on IgAV, collecting data on the spectrum of neurological manifestations. Results: We report on a 7-year-old girl with IgAV who presented with diplopia and afebrile focal seizures, which preceded the onset of purpura. Cranial magnetic resonance imaging was consistent with posterior reversible encephalopathy syndrome (PRES), showing typical focal bilateral parietal swelling and cortical and subcortical high signal intensities on T2-fluid attenuated inversion recovery (FLAIR) images predominantly without diffusion restriction. Cerebrospinal fluid analysis and blood tests excluded systemic inflammation or vasculitis. Interestingly, hypertension was not a hallmark of the developing disease in the initial phase of PRES manifestation. Renal disease and other secondary causes for PRES were also excluded. Supportive- and steroid treatment resulted in restitution ad integrum. Reviewing the literature, we identified 28 other cases of IgAV with CNS involvement. Severe CNS involvement includes seizures, cerebral edema, or hemorrhage, as well as PRES. Thirteen patients fulfilled all diagnostic criteria of PRES. The mean age was 11.2 years (median 8.0, range 5-42 years), with no reported bias toward gender or ethnic background. Treatment regimens varied from watchful waiting to oral and intravenously steroids up to plasmapheresis. Three cases showed permanent CNS impairment. Conclusion: Collectively, our data demonstrate that (I) severe CNS involvement such as PRES is an underappreciated feature of IgAV, (II) CNS symptoms may precede other features of IgAV, (III) PRES can occur in IgAV, and differentiation from CNS vasculitis is challenging, (IV) pathogenesis of PRES in the context of IgAV remains elusive, which hampers treatment decisions. We, therefore, conclude that clinical awareness and the collection of structured data are necessary to elucidate the pathophysiological connection of IgAV and PRES.

Mucosal passive immunization is the transfer of active antibodies from one organism to the mucosal surfaces of another organism for preventing or treating infectious diseases. Mucosal passive immunization has a great potential for the prevention and treatment of enteric infections like Rotavirus, which causes more than 114 million episodes of diarrhoea annually with a death toll of more than 450.000 per year. However, the high cost of recombinant antibodies with the current manufacturing systems based on mammalian cells hampers the production of the high antibody quantities required for passive immunization strategies. Alternative expression platforms such as plants could provide higher scalability and reduced costs. Moreover, the use of edible plant organs, which are Generally¿Regarded¿As¿ Safe (GRAS), could reduce manufacturing costs even further by easing the requirements for antibody purification. We analyze here the feasibility of utilizing fruits as inexpensive biofactories of human antibodies that can be orally delivered as crude extracts or partially purified formulations in mucosal passive immunization strategies. In the first section of this thesis, the construction of tomato plants producing a model human Immunoglobulin A (IgA) against rotavirus in their fruits is described. As a result, an elite homozygous line was obtained whose fruits produced on average 41 ¿g of IgA per gram of fresh weigh, equivalent to 0.69 mg IgA per gram of dry tomato powder. Minimally processed products derived from IgA¿expressing tomatoes were shown to strongly inhibit virus infection in an in vitro neutralization assay. Moreover, in order to make IgA¿expressing tomatoes easily distinguishable from wild¿type tomatoes, they were sexually crossed with a transgenic tomato line expressing the genes encoding Antirrhinum majus Rosea1 and Delila transcription factors, which confer purple colour to the fruit. The resulting transgenically¿labelled purple tomatoes contained not only high levels of recombinant neutralizing human IgA but also increased amounts of anthocyanins. In the second section of the thesis the composition of IgA¿expressing tomatoes was analyzed in search of possible unintended effects that could compromise the GRAS status of the final product. To this end, transgenic IgA¿tomatoes were compared with wild type tomatoes and also commercial tomato varieties using proteomic and metabolomic approaches. 2D¿DIGE gels coupled with LC¿MSMS for protein identification showed that all the uptrend differential proteins detected corresponded only to immunoglobulin chains or antibody fragments. On the other hand, non¿targeted metabolite data obtained by UPLC¿MS / Juárez Ortega, P. (2014). Production of recombinant Immunoglobulin A in plants for passive immunotherapy [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/37015