Immunoglobulin Y (IgY) is the major antibody found in eggs from chicken (Gallus domesticus). IgY can be used as an alternative to mammalian antibodies normally used in research, and its use in immunotherapy has recently been proposed. Compared to mammalian antibodies, IgY possesses several biochemical advantages and its simple purification from egg yolk prevents a stressful moment in animal handling, as no bleeding is necessary. Small amount of antigen (1 mg) can be used to elicit an immune response in chickens and there are low intra-individual differences regarding antibody concentration found in yolk. By studying two chicken breeds and their cross, a genetic correlation was shown regarding the IgY concentration, which implies a possibility by breeding to increase IgY concentrations. By using IgY instead of goat antibody as capture antibody in ELISA, it is possible reduce interferences by complement activation. After oral administration of IgY to healthy volunteers, IgY activity was present in saliva 8 hours later, indicating a protective effect. This effect has been studied in an open clinical trial with cystic fibrosis patients. Specific IgY against Pseudomonas aeruginosa given orally prolongs the time of intermittent colonization by six months, decrease the number of positive colonizations and might be a useful complement to antibiotic treatment. Immunoglobulin therapy may diminish the development of antibiotic resistant microorganisms. The use of immunoglobulin therapy broadens the arsenal available to combat pathogens in medicine and IgY is a promising candidate, both as an alternative to antibiotics and as a useful tool in research and diagnostics.

No description available.

Au cours des dernières années, Salmonella Enteritidis est devenus les sérotypes les plus souvent isolés chez les patients canadiens, les cas étant liés à la consommation de viande de poulet et d’œufs crus. Les vaccins tués commercialement disponibles pour la volaille, stimulent mal l'immunité mucosale, tandis que l'utilisation de vaccins vivants reste controversée. Par conséquent, un vaccin sous-unitaire par voie orale peut être une solution. Cinq protéines bactériennes ont été choisies comme candidates potentielles et identifiées, soit Glyceraldehyde-3-phosphate dehydrogenase, Enolase, Lipoamide dehydrogenase, DNA protection during starvation protein et Elongation factor-Tu. Notre objectif a été de produire et de purifier ces protéines et de démontrer leur immunogénicité. Les gènes des protéines ont été amplifiés et clonés dans le vecteur pQE-30 pour expression dans Escherichia coli M15. La purification a été effectuée par FPLC. Des poules pondeuses SPF ont été séparées en 6 groupes et injectées par voie intramusculaire à different âges avec une des 5 protéines, ou le PBS chez le groupe témoin. Les œufs ont été ramassés pendant l'expérience et du sang a été prélevé à 36 semaines d'âge. Les anticorps IgY ont été extraits à partir du jaune d'oeuf et du sérum, et les IgA à partir du blanc d'oeuf. Des immunodots, westernblots et ELISA ont évalué l'immunogénicité des protéines et les niveaux d'anticorps induits . Nous avons constaté que ces cinq protéines pourraient stimuler la production d'anticorps spécifiques in vivo. GAPDH, Enolase et DPS ont induit des titres d'anticorps plus élevés que LpdA et EF-Tu. / Over the past years, Salmonella Enteritidis (SE) has become the most prevalent serovars isolated in Canadian patients. Most cases in humans are associated with consumption of chicken meat, raw egg and related products. For controlling Salmonella transmission and infection in poultry, available commercially killed vaccines poorly stimulate mucosal immunity, while the use of live vaccines remains controversial. Therefore an oral subunit vaccine may be a solution. Five bacterial proteins were chosen as potential candidates and identified as Glyceraldehyde-3-phosphate dehydrogenase, Enolase, Lipoamide dehydrogenase, DNA protection during starvation protein and Elongation factor-Tu. Our objectives were to produce and purify these proteins and study their immunogenicity. The proteins genes were amplified and cloned into pQE-30 vector, then transformed into Escherichia coli M15 for expression. Purification was performed using FPLC. SPF laying hens were separated into 6 groups and injected intramuscularly 3 times at 16, 20 and 28 weeks of age. Five groups were injected with a single protein respectively while the sixth group was injected with PBS as control. Eggs were collected during the duration of the experiment and blood was collected when hens were sacrificed at 36 weeks of age. IgY was extracted from egg yolk and serum and IgA from egg white. Immunodot, westernblot and ELISA were used to evaluate the immunogenicity of proteins and antibody levels they induced. We found that these five proteins could stimulate production of specific antibody in vivo. GAPDH, Enolase and DPS induced higher antibody titer than LpdA and Ef-Tu.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Poor water quality is a global health concern affecting one billion people around the world. It is important to monitor water sources in order to maintain the quality of our drinking water and to avoid disease outbreaks. Targeting Escherichia coli as a faecal indicator is a widely used procedure, but the current methods are time consuming and not adequate to prevent spreading of faecal influence.   This Master thesis demonstrates the development of a near infrared fluorescence flow cytometer sensor system targeting Escherichia coli, using fluorescently labeled chicken IgY antibodies. The near infrared light was chosen to avoid fluorescence from blue-green algae that are present in the water source.   The hardware was developed with a 785  nm laser line to detect Alexa Fluor 790 labeled antibodies, using a photomultiplier tube or two different CMOS cameras. The antibodies were labeled using a commercial labeling kit, and evaluated using antibody binding assays and the developed hardware.   The IgY antibodies were successfully labeled with Alexa Fluor 790 and the function was maintained after the labeling process. The result demonstrates the principles of the sensor system and how it solved to the problem with fluorescence from blue-green algae. An aperture was used to overcome the suboptimal laser and filter setup, and to increase the sensitivity of the system. However, only a small fraction of the cells could be detected, due to challenges with the focal depth and loss of sensitivity in the photomultiplier tube at near infrared wavelengths. Further development is required to create a working product.

No description available.