Demonstration of hepatitis A virus in cell culture by electron microscopy with immunoperoxidase staining

Virus-like particles were demonstrated by electron microscopy in BS-C-1 cells infected with hepatitis A virus (HAV). Particles were usually enclosed within vesicles and accompanied by myelin-like membranous structures. Less often they were seen free in the cytoplasm. They were never observed in the nucleus. By immunoperoxidase staining particles were found to contain HAV antigens. These antigens were also found in the membrane of the vesicles surrounding the masses of particles and adjacent parts of the mitochondrial membranes. Our results demonstrate the usefulness of an electron microscopic immunocytochemical technique to study replication of HAV.