Ultrastructural localization by immunoperoxidase techniques of influenza virus antigens in abortive infection of L cells.

An abortive infection was induced in L cells by influenza virus A/Hong Kong/68 (H3N2). With the use of antibody and peroxidase-labelled protein A, the localization of virus protein synthesis but not the maturation of virus particles was demonstrated at the ultrastructural level. Five days after inoculation (p.i.), the synthesis of viral haemagglutinin was localized in the region of the rough endoplasmic reticulum; at late intervals p.i., haemagglutinin accumulated in the plasma membranes, where membrane vesicles, containing haemagglutinin in their membranes, were released from the cell surface. The cytoplasmic viral ribonucleoprotein was localized in the region of free cytoplasmic ribosomes and that of the outer sheet of the nuclear membrane. Viral proteins were detected in the cytoplasm and plasma membranes also after 70 and 390 days of passaging of the cells or of their long-term cultivation with regular change of medium.