Localization of hepatitis A antigen in marmoset organs during acute infection with hepatitis A virus.

Twelve marmosets (Saguinus mystax) were inoculated intravenously (iv) with hepatitis A virus (HAV). One died early (day 12); seven were sacrificed at the time of elevation in level of alanine aminotransferase (serum glutamic-pyruvic transaminase), and four without elevation were not sacrificed but seroconverted. In the seven marmosets sacrificed during the acute stage of illness, hepatitis A antigen (HA Ag) was detected in the liver by immunofluorescence in all cases, by immune electron microscopy in four, and by enzyme-linked immunosorbent assay (ELISA) in three. The HA Ag appeared by immunofluorescence as very fine granules in the cytoplasm of hepatocytes and Kupffer cells. The HA Ag could not be detected by immunofluorescence in biopsy specimens taken from the duodenum, jejunum, ileum, or transverse colon in any of eight marmosets in which necropsy was performed during the acute or preacute stage of illness. These findings suggest that the gut is not involved during the acute phase of HAV infection following iv inoculation into marmosets. The ELISA results showed that only three of 12 marmoset livers obtained during the acute phase of HAV infection could be used as an antigen source in serologic testing for antibody to HA Ag. Thus, marmoset livers were no better as a source of HA Ag than acute-phase stools from patients with type A hepatitis.