A packaging system for SV40 vectors without viral coding sequences.

SV40 vectors have been used as expression vectors for mammalian cells since the early 1980s. More recently, they have been used as gene transfer vectors in mice and in human peripheral blood cells. Here we described a system for packaging SV40 vectors without viral coding sequences. Recombinant adenovirus-expressing SV40 capsids can effectively package plasmids that contain the SV40 replication origin. The final yield of infectious SV40 vector is about 3 x 10(5), with a SV40 to adenoviral vector ratio of about 1000:1. Helper adenoviruses can be effectively heat-inactivated with no effect on the infectivity of SV40 vectors.