Characterization of the uptake and distribution of alginate microspheres by the chicken gastrointestinal tract and bursa of Fabricius, and, the effects of antigen-carrying alginate microspheres on cell-mediated, humoral and mucosal immunity
Abstract
Antigen-carrying alginate microspheres are a novel oral vaccine delivery system that has been shown to stimulate immunity in mammals but has not been thoroughly evaluated in chickens. This project consisted of three studies aimed at characterizing the gastrointestinal uptake of alginate microspheres in chickens and determining the effects of Salmonella enteritidis (SE) flagellin-carrying alginate microspheres on cell-mediated, humoral and mucosal immunity. In the first study, sections of duodenum, jejunum, ileum, cecum, cecal tonsil, colon and bursa of Fabricius (bursa) were incubated with eight different fluorescein-isothiocyanate-labeled lectins and the binding characteristics of the lectins were compared. It was found that lectins derived from tomato (TL) and wheat germ (WGA) had the highest affinity for the GI tract and bursa. In the second study alginate microspheres were coated with TL, WGA, poly-L-lysine and cholera toxin B subunit. Coated and non-coated microspheres were injected into segments of the duodenum, ileum, cecum, cecal tonsil, colon and bursa and their uptake and splenic and hepatic distribution was compared. It was found that coating alginate microspheres with WGA enhanced their uptake in the ileum and colon and that coating alginate microspheres with TL enhanced their distribution to the liver and spleen. In the final study alginate microspheres were loaded with SE flagellin, coated with WGA and administered to chickens either three times orally or once subcutaneously and twice orally. Cell-mediated immunity was assessed by the magnitude of the delayed-type hypersensitivity response to intradermally injected SE flagellin. Humoral immunity was assessed by measuring antigen (SE flagellin)-specific serum immunoglobulin (Ig)G and the induction of antigen-specific IgG, IgA and IgM-producing splenocytes. Mucosal immunity was assessed by measuring antigen-specific IgA in intestinal secretions and induction of antigen-specific IgG, IgA and IgM-producing lymphocytes in the cecal tonsil. It was found that oral administration alone or subcutaneous followed by oral administration of SE flagellin-carrying alginate microspheres stimulated cell mediated immunity and that only subcutaneous followed by oral administration of SE flagellin-carrying alginate microspheres stimulated humoral and mucosal immunity. Results of this project indicate that antigen-carrying alginate microspheres have the potential to be used as an oral vaccine delivery system in chickens.
Degree
Ph.D.
Advisors
Porter, Purdue University.
Subject Area
Veterinary services|Pathology|Immunology
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