Development and utilization of complement-fixation and immune adherence tests for human hepatitis A virus and antibody.

The reliable propagation of CR326 strain of human hepatitis A virus in Saguinus mystax marmosets has permitted the development of specific serum neutralization, complement-fixation (CF), and immune adherence (IA) assays for hepatitis A antigen and antibody. The CF and IA assay were made possible by the use of livers of CR326-infected marmosets as a source of hepatitis A antigen. All assays were shown to be specific for hepatitis A. Patients with hepatitis B did not show development of hepatitis A antibody. Hepatitis A antibody appeared following onset of illness, and, in the longest time period studied, has persisted for seven years. Epidemiologic studies have been performed on several Costa Rican families with outbreaks of hepatitis, with the IA and CF assays. Also, several populations in the U.S.A. were studied. These indicated a high incidence of hepatitis A at an early age in Costa Rica and a relatively low incidence of hepatitis A antibody among adults in the U.S.A. It was shown that human immune globulin can be standardized for hepatitis A antibody content by the IA assay. Finally, the IA assay indicated probable hepatitis A antibody in uninoculated chimpanzees, grivet monkeys, and rhesus monkeys.