(683g) Ragweed Pollen-Based Oral Vaccine Delivery

Oral vaccine delivery although highly desirable, continues to be a difficult target. This is because the harsh acidic and enzymatic environment together with physical and biological barriers in the gastrointestinal (GI) tract pose unique challenges to deliver vaccines orally. We have developed pollen grains (PGs) as a novel method to deliver antigens across the GI mucosa. In this study ragweed pollens were used to deliver ovalbumin (OVA) orally.

Ragweed pollens were chemically processed to remove native biomolecules and to obtain clean pollen particles. Mice were then immunized with a formulation of OVA and ragweed pollens. Immune responses were characterized by determining the presence of serum anti-OVA IgG, IgG1, IgG2a, IgE, fecal IgA, salivary IgA, and vaginal IgA antibodies using enzyme-linked immunosorbent assay (ELISA). Our study shows that vaccine formulations with ragweed pollens stimulated significantly higher antibodies compared to control mice that received only OVA without ragweed pollens. Using ragweed pollens, high OVA-specific systemic immune response was induced compared to control mice. Furthermore, anti-OVA IgA antibodies were stimulated not only in the intestinal mucosa, but at the distal vaginal mucosal site. Overall, our study demonstrates the potential of ragweed pollen for a simple method of oral vaccination that can induce systemic and mucosal immunity. Further study is required to optimize the antigen dose and frequency of the delivery system.