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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Acetylation, Animals, Anthrax, Anthrax Vaccines, Antibody Formation, Antigens, Bacterial, Bacillus anthracis, Bacterial Toxins, Dextrans, Drug Carriers, Imidazoles, Mice, Toll-Like Receptors, Vaccination, Vaccines, Subunit.
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Does rapid vaccination using an acetalated dextran microparticulate subunit vaccine confer protection against triplicate challenge by bacillus anthracis? Context: A rapid immune response is required to prevent death from Anthrax, caused by Bacillus anthracis. We formulated a vaccine carrier comprised of acetalated dextran microparticles encapsulating recombinant protective antigen (rPA) and resiquimod (a toll-like receptor 7/8 agonist). We were able to protect against triplicate lethal challenge by vaccinating twice (Days 0, 7) and then aggressively challenging on Days 14, 21, 28. A significantly higher level of antibodies was generated by day 14 with the encapsulated group compared to the conventional rPA and alum group. Antibodies produced by the co-encapsulated group were only weakly-neutralizing in toxin neutralization; however, survival was not dependent on toxin neutralization, as all vaccine formulations survived all challenges except control groups. Post-mortem culture swabs taken from the hearts of vaccinated groups that did not produce significant neutralizing titers failed to grow B. anthracis.
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Results indicate that protective antibodies are not required for rapid protection; indeed, cytokine results indicate that T cell protection may play a role in protection from anthrax. We report the first instance of use of a particulate carrier to generate a rapid protective immunity against anthrax. Final Decision: yes