[Persistence of the Sindbis virus in cultures producing oncornavirus]

Continuous lines were obtained from primary cultures of BALB/C mouse embryo cells which were found by electron microscope and reverse transcriptase reaction to produce permanently oncoronavirus type C after exogenous infection with Rauscher leukemia virus (RLV). Sindbis virus (SV) was inoculated into virogenic cultures 398 days after infection with RLV. The system in characterized by rapid (3-21 days) disappearance of the infectious arbovirus from the medium and the cells, long-term (over 5 months) persistence on SV noninfectious antigen and signs of stimulation of oncornavirus activity. The level of reverse transcriptase activity in cultures in the presence of persisting arbovirus was 1.5-3.3-fold higher than in cultures infected with RLV alone. Two variants of the course of mixed chronic infection of the cultures with oncornavirus and arbovirus differing in the rate of transition of the arbovirus into the noninfectious form and inhibition or stimulation of oncornavirus functions are discussed.