Particle-mediated delivery of recombinant expression vectors to rabbit skin induces high-titered polyclonal antisera (and circumvents purification of a protein immunogen).

Polyclonal antibodies were generated in rabbits by delivery to skin of gold particles coated with mammalian expression vectors encoding a cytoplasmic (beta-galactosidase) or a nuclear (L1 capsid of cottontail rabbit papillomavirus) protein. One primary and one booster immunization of 30 micrograms DNA per rabbit yielded specific antisera with titers from 1:24 000 to 1:120 000 in each of eight rabbits, as detected by ELISA and Western blot analysis. Genetic immunization requires relatively small amounts of DNA, eliminates the need to purify the protein immunogen, and does not require irritating adjuvants.