What generation are your lentiviruses? Why does generation matter?

Our lentiviruses are 2^nd generation. Generation matters when considering which packaging plasmids to use to produce the lentivirus particles. Briefly, our lentiviral transfer plasmids are meant to be used in a 3 plasmid 2^nd generation packaging system:

1. Lentiviral transfer plasmid – the lentiviral plasmid encoding your transgene (ie. pLV-SFFV-hNIS)
2. Packaging plasmid - encoding Gag, Pol, Rev, and Tat. Tat is essential for 2^nd generation packaging.
3. Envelope plasmid – encoding the envelope protein (usually VSV-G) 

3^rd generation lentiviruses encode Gag/Pol and Rev on 2 separate plasmids and the transfer plasmids are Tat independent. Thus 2^nd generation transfer plasmids (Imanis products) CANNOT be packaged by 3^rd generation systems since 3^rd generation systems do not include Tat expression.