Sequential Ultrastructural Changes of WISH Cells Infected with Encephalomyocarditis Virus

The objective of the present study is to evaluate the sequential ultrastructural changes due to encephalomyocarditis virus (EMCV) infection in human amnion derived WISH cells. The effects of recombinant human interferon-alpha (IFN-α) on viral multiplication and cell morphology were assessed in WISH cells. Supernatants and pellets obtained from EMCV- infected WISH cells, pre-treated or not with IFN-α, for 18, 24 and 36 h were used. Electron microscopy was employed to evaluate the fine cellular changes. EMCV infection within 24 h led to partial damage of the cell population with signs of organellar damage. Cellular alterations were clearly evident at late-phase of infection. Presence of the viral particles was much less evident in infected Wish cells pre-treated with IFN-α which did not pose any damage to WISH cells. Intracytoplasmic localization of EMCV in WISH cells may well reflect the sites of viral replication. The presence of virus particles in cell membrane protrusions and in vacuoles indicates that virus is possibly released not only by disintegration of the infected cells but also via exocytosis. It is also postulated that EMCV is released from infected WISH cells by budding in a low steady phase manner. It is concluded that IFN-α has an inhibitory effect on the EMCV replication activity.