Induction of protective immunity against lethal anthrax challenge with a patch.

Area of Science:

• Immunology
• Vaccinology
• Biodefense

Background:

• Transcutaneous immunization (TCI) utilizes epidermal immune cells for needle-free antigen delivery.
• A novel dry adhesive patch system was developed for a subunit anthrax vaccine to improve administration and tolerability.
• Addresses unmet needs in biodefense against anthrax.

Purpose of the Study:

• To evaluate the efficacy and immunogenicity of a novel dry adhesive anthrax vaccine patch.
• To compare TCI via patch with traditional intramuscular vaccination.
• To assess the potential for protection against aerosolized anthrax.

Main Methods:

• Mice and rabbits received recombinant protective antigen of Bacillus anthracis and E. coli heat-labile toxin via patch or injection.
• Monitored serologic changes, toxin-neutralizing antibody (TNA) levels, and pulmonary/nodal responses.
• Utilized a lethal aerosolized B. anthracis challenge model in A/J mice to demonstrate efficacy.

Main Results:

• TCI patch vaccination induced systemic immunity and protection comparable to intramuscular vaccination.
• Peak immunity was achieved with only two doses of the vaccine patch.
• Adjuvant inclusion in the patch resulted in superior TNA levels compared to injected vaccines.

Conclusions:

• Anthrax vaccine patches stimulate robust, functional immune responses and protect against lethal challenge.
• Observed lung responses suggest a protective mechanism against aerosolized anthrax spores.
• The stable, scalable, and feasible dry adhesive patch warrants clinical evaluation for anthrax vaccination.