Vector titers are determined by Q-PCR.
For LV vector titration, genomic DNA isolated from target cells transduced with LV vector, is subjected to Q-PCR to determine the number of integrated LV vector genome using primer and probe specific to the vector sequence. LV vector titers are reported as IU/mL, where IU is infectious units and represents the number of infective viral particles. Since the delivered LV vector is stored at -80°C, the LV vector titer is performed on vector preparations that have been stored at -80°C and thawed.
For AAV vector titration, a small aliquot of AAV vector preparation is subjected to Q-PCR using primers specific to vector promoter. AAV vector titers are reported as GC/mL, where GC is genome copies and generally represents the number of viral particles with a genome. As with LV vector titering, AAV titering is also performed on vector preparations that have been stored at -80°C and thawed.