Complement-fixing immunoglobulin M antibody response in patients with infantile gastroenteritis.

Complement-fixing immunoglobulin M antibody to infantile gastroenteritis virus (a rotavirus) was detected with highest sensitivity when the antibody-antigen-complement mixture was incubated at 37 degrees C for 1 h prior to the addition of sensitized sheep erythrocytes. Sucrose gradient centrifugation of sera collected sequentially from four patients after infection detected 19S complement-fixing antibody up to 5 weeks, with highest titers at 1 week, after the onset of illness. Treatment of the whole sera with 2-mercaptoethanol decreased complement-fixing titers only up to 2 weeks after onset of illness.