FIG. 2.

An optimized PRE sequence (oPRE) can replace wPRE without affecting LVV titer or transgene expression. (A) PBLs from at least three patients were transduced with serial dilutions of pRRL-cPPT-MSCVU3-GFP-Wsin or pRRL-cPPT-MSCVU3-GFP-Osin. Eight days posttransduction, GFP-expressing PBLs were detected by FACS. No significant difference in GFP expression was observed between wPRE and oPRE LVV constructs. Titers are presented as transducing units (TU) per milliliter, with error bars representing the standard error of the mean. (B) Dilutions of GFP-encoding vector were used to transduce PBLs and then GFP expression was measured at either day 6 or day 30 by FACS. No significant difference in GFP expression was observed between the wPRE and oPRE LVV constructs at any of the dilutions tested.