Development of a rubella virus DNA vaccine.

Two rubella virus DNA vaccines were constructed from a cDNA clone of the rubella virus genomic RNA, one which contained the coding sequences for all three virion proteins (C, E2 and E1) and one which contained the two envelope glycoproteins (E2 and E1). When used to immunize mice via gene gun delivery, both constructs induced an antibody response of equivalent titer to that induced by rubella virus that persisted for at least seven months. A booster injection given four weeks after the initial injection increased antibody titers by over thirty-fold. The antibody response in DNA vaccine-injected mice was directed primarily against the E1 glycoprotein, as was the case in rubella virus-injected mice, and neutralizing activity was detected. These DNA vaccines are thus prototypes for a nonreplicating rubella virus vaccine that could be used in specialized circumstances.