- Volume 49, Issue 1, 1980

Fluorescent antibody (FA) studies of cells infected with bovine enterovirus showed cytoplasmic blebs with specific fluorescence to the virus. These structures were also found extracellularly in the debris of lysed cells and were RNA-positive by acridine orange (AO) staining. The morphology of virus-infected cells was further studied by scanning electron microscopy (SEM). Transmission electron microscopy (TEM) with immunoferritin tagging showed the development of long sacs with bilaminated and multilaminated membranes. These sacs had multiple twists at different intervals along their length forming a chain of vesicles. The development and maturation of the virus were observed in these vesicles. A number of virus-containing vesicles were also present extracellularly in the debris of lysed cells. In addition, virus was observed in layers of membranous cisternae closely associated with vacuoles and plasma membrane. Some of the cisternae opened to the extracellular space and appeared to allow the release of the virus. Virus particles were also found in patches and in crystals within the cytoplasmic matrix. Many lysed cells contained fibrils often associated with patches of ferritin-tagged virus. This study presents morphological evidence for the release of the virus in vesicles after cell lysis, via cisternae with openings to the extracellular space, and in cytoplasmic blebs.

Conditions are described for the large scale production of mouse interferons from Ehrlich ascites tumour cells cultured as monolayers in roller bottles. With the procedure reported here, we have used 50 to 65 600 cm2 roller bottles to produce routinely 2 × 109 to 3 × 109 International units of crude mouse interferon/week with a specific activity of 1 × 106 to 1.5 × 106 units/mg protein.

Some notable aspects of the ultrastructure of cells infected by pittosporum vein clearing virus are illustrated. Although the majority of the virions were bullet-shaped and did not exceed 240 nm in length some particles were unusually long reaching 1.5 µm. These particles were individually enveloped in membraneous tubules and occurred in the ground cytoplasm or in connection with cell wall outgrowths, whose formation they may elicit.