Protective Immunity to Rotavirus-Induced Diarrhoea Is Passively Transferred to Newborn Mice from Naive Dams Vaccinated with a Single Dose of a Recombinant Adenovirus Expressing Rotavirus VP7sc

VP7sc is a novel rotavirus antigen engineered for presentation at the cell surface. Several recombinant viruses were constructed in which VP7sc was inserted into the E3 region of the human type 5 adenovirus (Ad5) genome and expression and transport of the antigen was monitored in cultured 293 cells. The recombinant virus showing the greatest level of expression (Ad5/7.4) was then used to determine whether antibodies to VP7sc could be induced in a nonhuman host. BALB/c and CBA/H mice were inoculated with Ad5/7.4 by iv, ip, oral and intranasal routes and serum antibody levels were assayed by ELISA. All vaccinated animals seroconverted but, depending on the route of vaccination, not all animals showed a significant secondary response following re-inoculation. The ability of Ad5/7.4 to induce protective immunity in mice was also examined using several vaccination regimes. A single dose of Ad5/7.4 given intranasally to dams not previously exposed to rotavirus was sufficient to induce immunity which could be passively transferred to protect suckling neonates. Recombinant adenoviruses expressing protective antigens therefore may provide an alternative to the use of attenuated rotaviruses in the development of a vaccine against gastroenteritis.