[Immunofluorescence and electron microscopy study of bovine reovirus multiplication in cell culture]

The appearance and development of reovirus antigens was followed up in Vero cells. The earliest immunofluorescence finding was established at the 6th hr, consisting in the appearance of small shining granules in and around the nuclear cytoplasm. At the 24th hr in 15 per cent of the cells there was a positive immunofluorescence finding in the form of one or several objects grouped closely to the nucleus. At the 36th hr fluorescence was seen in about 50 per cent of the cells to surround the nucleus and fill the whole cytoplasm or appearing as a limited and demarkated one. By form the fluorescent objects resembled viral inclusions. The immunofluorescence finding reached its peak at the 48th hr. In cells infected with Reo 2 the appearance and cumulation of the virus antigen ran its course in the same sequence as that seen with Reo 1, however, it was manifested with higher intensity. The electron-microscopic study of Reo 1-infected cells revealed greater diversity in the stages of infection as early as the 24th hr--from the appearance of sporadic virions up to the emergence of large virus crystals the virions in which assumed square or hexagonal arrangement. There was also linear arrangement of the virions by the length of the tubular cell structures. Cells infected with Reo 1 and Reo 2 presented likewise zones with large masses of virus matrix prior to the appearance in them of new virions. There was also particular cumulation of the cell ribosomes along with the matrix formation. It is believed that the appearance of these formations is associated with the virus morphogenesis.