Oral Immunization with Helicobacter Pylori-loaded Poly(D, L-lactide-co-glycolide) Nanoparticles

Background: Helicobacter pylori is a major cause of chronic antral gastritis and peptic ulcer diseases. Many researchers have examined the possibility of immunologically-mediated prevention of H. pylori infection using an oral vaccine. The purpose of this study is to investigate whether mucosal and systemic immune responses are induced by oral immunization with H. pylori lysate-loaded poly(D, L-lactide-coglycolide)[PLG] nanoparticles, and if so, how the distribution of serum IgG subclasses are produced.

Methods: PLG nanoparticles (H. pylori-PLG) with encapsulated H. pylori lysates were prepared by the solvent evaporation method, and the physical properties of the nanoparticles were investigated. Following the oral immunization of the H. pylori-PLG nanoparticles into mice, antibody induction was assayed in serum and gut washings, and the pattern of serum IgG subclasses was determined by ELISA.

Results: The prepared H. pylori-PLG nanoparticles were spherical, nonporous particles with a mean diameter of less than 1 microm. The multiple oral immunization with H. pylori-PLG nanoparticles induced significantly H. pylori-specific mucosal IgA response as well as serum IgG responses. The serum antibody subclasses elicited were predominantly IgG1 and IgG2b.

Conclusion: Our results suggested that oral immunization of H. pylori-PLG nanoparticles induced the H. pylori-specific mucosal and systemic responses in mice and enhanced Th2-type responses.