Fig. 3. Immunogenicity of single and six component OspA-ferritin nanoparticles in mice.

Transmission electron microscopy of OspA-ferritin serotypes 1–5, and 7 purified from E. coli (×68,000) (a). Immunogenicity of hexavalent vaccine in mice (b) C3H mice (n = 5) were immunized intramuscularly at weeks 0 and 4 with the indicated vaccine mixed with Alum and ELISA titers were analyzed 2 weeks later. The hexavalent vaccine included OspA from serotypes 1,2,3,4,5,7 at the molar equivalent of 1 µg each for a total of 6 µg, while the monovalent vaccine contained the molar equivalent of 1 µg of OspA plus 5 µg of empty ferritin particle. Empty ferritin alone is below the limit of detection. ELISA plates are coated with the specified serotype of OspA.