Prevention of Human Rotavirus-Induced Diarrhea in Gnotobiotic Piglets using Bovine Antibody

The efficacy of passively administered bovine antibody for preventing human rotavirus (HRV)-induced diarrhea was investigated using a gnotobiotic pig model. Cows were immunized with inactivated HRV serotypes 1 (Wa) and 2 (S2) and simian rotavirus serotype 3 (SAIl), and immune colostrum and milk were collected. Antibody concentrates derived from these materials were fed to germ-free piglets that were subsequently inoculated with HRV Wa. Both viral shedding and diarrhea were effectively reduced or eliminated in a dose-dependent manner as a result of HRV immune antibody feeding. A quantitative virus-neutralizing (VN) antibody method permitted assessment of the functional antibody dose required to achieve a 50% reduction of disease (PD50) . PD50 dose levels of 15.8 and 19.5 × 106 VN antibody units were determined for inhibition of diarrhea and viral shedding, respectively. Studies reported here provide new information on the quantitative relationship between protective antibody dose and diarrheal disease response.