DNA VACCINES AGAINST ROTAVIRUS INFECTIONS

Plasmid DNA vaccines encoding for murine rotaviral proteins VP4, VP6, and VP7 were tested in adult BALB/c mice for their ability to induce i mmune responses and provide protection against rotavirus challenge. Se rum antibodies were measured by virus neutralization and by ELISA. Cel lular immunity was assessed by measuring cytotoxic T cell (CTL) respon ses. The vaccines were administered by inoculation into cells of the e pidermis with an Accell gene gun (Auragen, Inc., Middleton, WI, USA). Each of the three vaccines elicited rotavirus-specific serum antibodie s as measured by ELISA. Virus neutralizing antibodies were detected in mice receiving DNA vaccines encoding for VP4 and VP7, but not in thos e which received the plasmid encoding for VP6. Vaccines encoding for V P4, VP6, or VP7 generated virus-specific CTL responses in recipient mi ce. Efficacy of the vaccines was determined by challenge with homotypi c rotaviruses. Each of the three vaccines was effective in protecting mice against infection after rotavirus (100 ID50) challenge. Significa nt reductions (p <0.0002, analysis of variance) in viral excretion mea sured over a 9 day period were seen in mice receiving the DNA vaccines compared with mice that received control plasmids.