Study rBV A/B-CL-001 is a Phase 2b, 2-part, open-label, uncontrolled study to evaluate safety, tolerability, and immunogenicity of a single dose of recombinant botulinum vaccine A/B (rBV A/B) for the production of BabyBIG in volunteers previously immunized with the pentavalent botulinum (PBT) toxoid. This study is designed to determine neutralizing antibody levels for botulinum toxin types A and B in healthy subjects who were previously immunized with the PBT for occupational protection and who receive the rBV A/B. Subjects with titers of the neutralizing antibodies against the toxins would be candidates for plasma donation for BabyBIG production.