Effect of human immune serum globulin on infectivity of hepatitis A virus.

A standard preparation of immune serum globulin containing a titer of immune adherence hemagglutination hepatitis A antibody of 1:3,200 neutralized the infectivity of MS-1 serum. An inoculation of MS-1 serum was followed by the following evidence of hepatitis A infection in eight of 14 seronegative recipients: (1) abnormal values for serum aspartate aminotransferase after an incubation period of 29-42 days, and (2) no detectable immune adherence hemagglutination hepatitis A antibody (less than 1:5) before exposure, and an eightfold or greater increase in antibody titer during convalescence. In contrast, inoculation of the mixture of MS-1 serum and immune serum globulin was followed by (1) normal values for aspartate aminotransferase in all eight seronegative recipients, and (2) evidence of an antibody response (indicating subclinical infection) in two of the eight. Under the conditions of this study, the use of the preparation of immune serum globulin described prevented or modified hepatitis A infection.