The objective of this project is to examine new vaccine delivery systems for the mucosal and parenteral administration of pertussis antigens. The B pertussis protein Tcf has been expressed in Vibrio cholerae using the E.coli nirB promoter. Mice were immunized four times intranasally with recombinant Vibrios prior to challenge with an aerosol of B. pertussis. Intranasal administration of V. cholerae expressing Tcf induced a significant reduction in bacterial colonization of the tracheas compared to animals immunized with V. cholerae alone. Such an outcome is consistent with the proposed role for this protein in tracheal colonization. We have also begun to explore the use of attenuated strains of V. cholerae as an oral delivery system for pertussis antigens. Germ-free mice can be successfully colonized for up to 28 days with V. cholerae, and, in fact, develop significant titers of serum vibriocidal antibodies. Future experiments will examine the ability of V. cholerae that express the B. pertussis antigen FHA to elicit a specific immune response that will protect against pertussis infection. A project to evaluate DNA vaccines as a means of generating a protective response to B. pertussis antigens has been initiated.
