Respiratory syncytial virus-specific RNA synthesis in primary monkey kidney cell cultures

Primary rhesus monkey kidney (MK) cell cultures were inoculated with respiratory syncytial virus and treated or untreated with actinomycin D before pulse labeling with uridine-5-3H. The virus-specific RNA synthesis was noted at its peak in the nucleoplasm and possibly less so in the cytoplasm of infected cells. At 48 and 72 hours post-inoculation (p.i.), small fractions of available cells were synthesising virus-specific RNA with labeling index of 15% and 18% respectively. By 48 hours p.i. syncytia started appearing and a higher grain count in the cytoplasm of actinomycin D-treated infected cells was noted.