ABSTRACT
This chapter reviewed the studies of live oral HRV and inactivated HRV candidate vaccines evaluated in a Gn pig model. Two to three doses of attenuated Wa HRV oral inoculations conferred 34% and 62% against diarrhea and 19% and 67% protection against virus fecal shedding, respectively in Gn pigs. After infection with virulent Wa HRV, Gn pigs were totally protected from reinfection. The protection is positively correlated with magnitudes of HRV-specific intestinal antibody-secreting cell and IFN-γ producing T cell responses. Studies of magnitude, tissue distribution, and dynamics of humoral and cellular immune responses induced by virulent HRV infection and HRV vaccines established basic parameters related to immune protection in the Gn pig model of HRV-induced disease, verifying the usefulness of this model to examine new strategies for the design and improvement of HRV vaccines. Two inactivated whole rotavirus vaccine candidates have been evaluated in Gn pigs. The chemically (binary ethylenimine) inactivated Wa HRV did not confer protection while the physically (heat treatment for 6 h) inactivated CDC-9 HRV demonstrated substantial protection against virus shedding. For both vaccines, there is no notable association between higher serum antibody responses induced by these vaccines and a higher degree of protection against rotavirus diarrhea.
