The multiplication of Sericesthis iridescent virus in cell cultures from Antheraea eucalypti Scott I. Qualitative experiments

Abstract

Cultures of Grace's Antheraea eucalypti cells have been successfully infected with Sericesthis iridescent virus (SIV). Virus antigen and DNA (shown by fluorescent antibody and acridine orange staining, respectively) accumulated in discrete foci in the cytoplasm of infected cells. Cells containing such foci were first seen about 2 days after infection at 25° or 3 days at 21°; the proportion of cells which contained foci increased to reach a maximum after 4 days' incubation at 25° or 6 days at 21°. The size and intensity of fluorescence of the foci increased until the cytoplasm of many cells was filled with viral products. The cytoplasmic foci were shown by electron microscopy to contain aggregations of complete virus particles, developmental forms resembling those of Tipula iridescent virus, and diffuse material which stained with uranyl acetate. Single virus particles were also present elsewhere in the cytoplasm and in long processes extending from the cell surface. They appeared to separate from these by a budding process and acquired an envelope derived from the cell membrane. Seven consecutive passages of SIV in A. eucalypti cell cultures were successful at 21°, but infectivity was lost after two passages at 25°.