Retroviruses prepared from human DAF expressing murine packaging cells acquire resistance against human serum

The complement system of the human body inactivates the infectious ability of retroviruses injected as an artificial gene transfer vector. We establis hed new murine leukemia virus (MuLV) packaging cell lines; D2SS and D7S whi ch express decay-accelerating factor (DAF) on their surface. Both D2SS and D7S were resistant against incubation with fresh human serum. Moreover, the retroviruses produced from these packaging cell lines were also resistant to serum treatment. This resistance can be inhibited by DAF neutralizing an tibody 1C6. These data demostrate that DAF induces a partial protection of MuLV infection from the human complement system.