Evaluation of the antibody response and uptake of ca-alginate microspheres containing model antigen after oral immunization

Oral delivery system has numerous advantages; however some peptide and protein drugs may occurs degradation by gastrointestinal enzyme when given orally. Ca-alginate microspheres containing model antigen Ovalbumin were prepared to protect ovalbumin from degradation by forming microspheres to enhance immune response and uptake of microspheres by lymphoid tissue in mice’s intestine. Ovalbumin-alginate microspheres were produced by aerosolization technique using Na-alginate polymer and CaCl₂ cross-linker. To increase stability during storage, microspheres were dried with 5% maltodextrin as lyoprotectant. To observe immunological evaluation, hemagglutination test by measuring antibody titre was conducted for all groups compared to vaccine product which administered via intra muscular route. In vivo uptake study of microsphere in mice’s villi and Peyer’s patches at different time series were performed by labelling microspheres with rhodamine B. IgG titre immune response of Ca-alginate microspheres containing ovalbumin increased when compared to blank microspheres and ovalbumin solution. BSA had similar titre as ovalbumin-alginate microspheres. In addition, lyophilized ovalbumin-loaded alginate microspheres with 5% maltodextrin produced the highest IgG titre. Interestingly, freeze-dried ovalbumin-loaded Ca-alginate microspheres showed equal immune response as intra muscular vaccine product. For uptake study in the intestine, it resulted both ovalbumin-alginate microspheres with and without 5% maltodextrin were able to be taken up by villi at 6 hours after given orally and taken up further by villi and Peyer’s Patches at 7 to 10 hours. In conclusion, ovalbumin-loaded Ca alginate microspheres with 5% maltodextrin indicated that the Ca-alginate microspheres entrapping ovalbumin have potential to enhance immune response and facilitate the uptake.