Mixing of M segment DNA vaccines to Hantaan virus and Puumala virus reduces their immunogenicity in hamsters

To determine if DNA vaccines for two hantaviruses causing hemorrhagic fever with renal syndrome, Hantaan virus and Puumala virus, are immunogenic when given in combination, we delivered them to hamsters separately or as mixtures by gene gun or by electroporation. Both vaccines elicited neutralizing antibodies when given alone but when they were delivered as a mixture, antibodies to only one of the two hantaviruses could be detected. In contrast, if the DNAs were given as separate vaccinations to a single animal, responses to both were observed. These studies suggest that the two DNA vaccines will need to be given as separate administrations.