Prophylaxis of rotavirus gastroenteritis using immunoglobulin

Abstract

Oral inoculation of the human group A rotavirus MO strain (G serotype 3) into 5-day-old BALB/c mice causes gastroenteritis characterized by diarrhea. Using this small animal model, passive protection of suckling mice against human rotavirus infection was achieved with the use of immunoglobulin (IgY) from the yolks of eggs of rotavirus-immunized hens. When IgY against the rotavirus strain homotypic with the challenge virus (MO strain) was administered to mice, complete protection was achieved. After immunizing 8-month old pregnant Holstein cows with human rotavirus MO strain, colostrum containing neutralizing antibody to four different G serotypes of human rotavirus, designated Rota colostrum, was obtained. Rota colostrum completely protected suckling mice against rotavirus infection, and purified IgG obtained from Rota colostrum protected against infection with the homologous virus. After randomly grouping 20 infants from a baby care center, 10 infants received 20 ml of Rota colostrum for 2 weeks and 10 control infants received none. Rotavirus-associated diarrhea developed in 7 of the 10 infants in the control group. None of the three infants in the group daily receiving the Rota colostrum had such symptoms, and one of three infants in the group receiving treatment, every other day developed rotavirus-induced diarrhea. Oral administration of Rota colostrum seems to be an effective and safe means of preventing diarrhea caused by human rotavirus infection. Recently, the immunized cows were boosted by reinjection of 4 serotypes of human rotavirus into a superficial cervical lymph node two weeks after delivery, resulting in mass production of cow's milk containing a high-titered antibody to human rotavirus. Therefore, the hyperimmune cow's milk is a candidate for a "physiologically functional food" in Japan.