Development of a Microbead Whole Cell Delivery System for Oral Immunization against traveler's diarrhea

Antex biologics is developing inactivated whole cell vaccines for oral delivery to prevent infections by bacteria causing traveler's diarrhea. A new, possibly breakthrough, microbead formulation technology is being developed which should be evaluated forits potential to enhance these inactivated whole cell vaccines. These beads should improve the safety, stability and immunogenicity as well as ease of administration of the whole cell vaccine. In this Phase I SBIR, Campylobacter jejuni, a major cause ofdiarrhea, will be prepared as a dry formulation by spray-coating the inactivated bacterial cells onto a sugar/starch microbead core and then covering the antigen-coated core with a methacrylic acid copolymer. The microbeads will be insoluble at gastricpH, but will be readily soluble at higher (intestinal) pH. This formulation will be tested for its oral immunogenicity and efficacy in a mouse model Antex has developed.This effort should provide a means to better achieve immunoprotection against entericinfections, for which no vaccines are now available. It may also establish an approach for more effective oral vaccines against a broad range of infections. Potential populations for use of such a product include deployed military personnel, internationaltravelers, and global and national public health and child immunization programs.