– Robust LV manufacturing platform:
The recombinant lentivirus vectors are prepared with a plasmid containing the transgene flanked by long terminal repeats (LTRs), co-transfected with the envelope expressing plasmid and the gag-pol plasmid. Once packaged into our production/complementing cell line, the recombinant lentiviral vectors are produced at high titers.
– Lentivirus plasmid vector and co-transfection in complementing cell line for virus production:
The gene of interest (GOI) is cloned into one of the LTR/MCS-containing lentivirus vectors, which could be subjected to specific modifications and improvements, before generating the pLV-GOI. By means of co-transfection for effective replication and packaging, the supernatant containing lentivirus particles is collected at 24 hours, 48 hours and 72 hours post transfection, with continuous replacement of the culture medium after transfection.
– Medium / large scale production under GLP:
Flexible capabilities for process optimization and production are available; shake flask cultures, bioreactors of 1L, 3L and 20L capacity.
– Upstream process and downstream processing
Process development steps were fully developed in our Laboratories for optimized recovery and clarification of LV from the culture supernatant. The implementation of process intensification strategies allows high cell densities at the time of transfection The supernatant containing lentivirus particles is collected everyday after transfection until final harvest. Continuous fresh medium replacement is performed after transfection. The downstream processing is also fully scalable, consisting of concentration step, capture by ion exchange chromatography and buffer exchange and formulation.
– Quality control analysis of lentiviruses
For Quality Control, the measurement of the virus titer (as genome copies/mL) is performed for the LV produced. Tittering is performed using digital droplet PCR (ddPCR) with primers targeting the CMV promoter present in the viral genome. Quantification based on specific detection of the gene of interest is also conducted. Additional quality control services can be added upon request. If GFP is present, the lentivirus titer is estimated based on the number of fluorescent positive cells. After lentivirus titer detection, the transducibility and functionality of the LV produced needs to be evaluated before animal experiments in order to test the gene expression.
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