Our production system utilizes 3rd generation packaging vectors, which are compatible with 3rd generation transfer vectors.

• 1st Generation vectors contain all HIV genes minus the envelope protein.
• 2nd Generation vectors contain a wild-type 5' LTR. Transcription of these vectors requires Tat, which is supplied by a separate vector.
• 3rd Generation vectors utilize a chimeric 5’ LTR to ensure transcription in the absence of Tat.

It is important to understand which generation your transfer vector is because 2nd generation vectors cannot be packaged with 3rd generation packaging vectors.