Protection of mice against rotavirus challenge following intradermal DNA immunization by Biojector needle-free injection

Mucosal administration (intranasal or oral) of a VP6 rotavirus vaccine to mice consistently elicits high levels of protection after rotavirus challenge (93–> 99% reductions in fecal rotavirus shedding) but only when co-administered with an effective adjuvant such as LT(R192G). Here, we showed that Biojector needle-free injection of VP6-encoded plasmids also induced protection (85–93%) when they were co-administrated with LT(R192G)-encoded plasmids. A reduction in the amount of VP6 plasmid from 50 to 10 μg reduced protection from 93 to 70%, but the immunized mice remained significantly (P < 0.05) protected. Intramuscular needle injection of VP6/LT(R192G)-plasmids also induced significant protection (66%).