- Multi-plasmid DNA vaccination avoids antigenic competition and enhances immunogenicity of a poorly immunogenic plasmid. Grifantini, R., Finco, O., Bartolini, E., Draghi, M., Del Giudice, G., Kocken, C., Thomas, A., Abrignani, S., Grandi, G. Eur. J. Immunol. (1998)