Characterization of IgY for Oral Immunotherapy and Prevention of Pseudomonas aeruginosa Infections in Cystic Fibrosis Patients

Abstract: Chicken antibodies, commonly referred to as IgY, have several properties that make them suitable for oral treatment of infections and there is essentially no risk for development of resistance. The overall aims of this thesis were to investigate Anti-Pseudomonas IgY as prophylaxis against infections with Pseudomonas aeruginosa for cystic fibrosis (CF) patients and to characterize the antibody treatment.We found that Anti-Pseudomonas IgY has affinity for P. aeruginosa flagellin, the major component of the flagellum. This is important since the flagellum is required for host invasion and establishment of infection. Flagellin induces inflammation.The main cause of morbidity and mortality among CF patients is chronic colonization of the airways with P. aeruginosa. We have studied prophylactic treatment of 17 Swedish CF patients with Anti-Pseudomonas IgY for up to twelve years. The results were compared with a control group of 23 Danish CF patients. Patients treated with IgY had 2.3 P. aeruginosa positive cultures/100 treatment months vs. 7.0 cultures/100 treatment months in the control group (p=0.028), and the time from inclusion to the first recolonization was significantly longer in the IgY-treated group (p=0.012). Lung function was preserved and patients treated with IgY had good nutritional status at the end of the study. Furthermore, other bacteria have not emerged instead of P. aeruginosa.Freeze-drying of IgY and the content of IgY preparations for oral use was investigated. Besides IgY, 26 egg yolk proteins were identified. Some of the proteins are known to have antimicrobial and immunostimulatory effects, and could have a positive additive effect to IgY treatment. Cholesterol levels were low.Conclusion: Anti-Pseudomonas IgY is a promising complement in the prevention of Pseudomonas aeruginosa infections in CF patients, partly explained by the fact that IgY binds to flagellin.