Table 1.

Comparison of the functionality of the MDEV Env expression plasmidsa

PlasmidLAPSN titer (AP+ FFU/ml)b
pBSIIKS+<5
pSX21 × 105
pMDEV9ex2 × 103
pMEXp l a s m i d 2 × 103
pMEXd u n n i 2 × 103
  • a LGPS/LAPSN cells were plated at 5 × 105 cells per 6-cm-diameter dish on day 1. On day 2, 10 μg of each plasmid DNA was transfected in duplicate dishes by calcium phosphate precipitation. The medium was replaced on day 3 and harvested on day 4 and centrifuged at 4,000 × g for 5 min at 4°C to remove cells and debris. Virus titration was performed as described previously (11) on D17 cells (ATCC CCL183). Cells were cultured in Dulbecco’s modified Eagle’s medium with 10% FBS.

  • b The titers are means of the values obtained from the duplicate transfections.