Immune adherence and complement-fixation tests for human hepatitis A. Diagnostic and epidemiologic investigations.

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 assays 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. Cases of 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 7 years. Epidemiologic studies have been performed on several Costa Rican families with outbreaks of hepatitis, using 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.