IgG1 antibody in milk protects lambs against rotavirus diarrhoea.

Newborn gnotobiotic lambs were fed a diet of diluted evaporated milk supplemented either with normal ewes' milk or with milk obtained from ewes injected parenterally during gestation with rotavirus. Lambs fed 150 ml per day of milk collected 5 days after lambing from normal ewes were susceptible to rotavirus infection and diarrhoea, while lambs fed milk from vaccinated ewes collected either 5 or 12 days after lambing were protected. Analysis of the milk by column chromatography showed the anti-rotavirus activity to be in the fractions containing IgG1.