Recombinant V antigen protects mice against pneumonic and bubonic plague caused by F1-capsule-positive and -negative strains of Yersinia pestis

The purified recombinant V antigen from Yersinia pestis, expressed in Escherichia coli and adsorbed to aluminum hydroxide, an adjuvant approved for human use, was used to immunize outbred Hsd:ND4 mice subcutaneously. Immunization protected mice from lethal bubonic and pneumonic plague caused by CO92, a wild-type F1(+) strain, or by the isogenic F1(-) strain C12. This work demonstrates that a subunit plague vaccine formulated for human use provides significant protection against bubonic plague caused by an F1(-) strain (C12) or against substantial aerosol challenges from either F1(+) (CO92) or F1(-) (C12) Y. pestis.