[Pilot-scale preparation of clinical-grade third generation lentivirus]

Gene therapy is a rapidly developing field. The most widely used technique for foreign gene transfer is lentiviral-mediated gene therapy. Lentiviral vector has been developed from the first generation to the third generation in terms of safety. The preparation of lentiviruses with high titer remains difficult. In this study, a Fibra-Cel sheet carrier was used as an HEK293T cell carrier matrix, and several sterile cell culture spinners were combined and cultured on a roller bottle machine to scale up the adherent cells. The virus titer was maximized by screening the factors to optimize the lentivirus titer in the third-generation lentivirus packaging process one by one. Fibra-Cel sheet vector was successfully used as the matrix of HEK293T cell adhesion to culture adherent cells at large scale. The optimal conditions for large-scale preparation of the third-generation lentivirus by bottle roller were screened and three batches of lentiviruses were produced on pilot scale. The production time of lentivirus was shortened from 120 hours to 54 hours from plasmid transfection to virus collection; in terms of cost, a rolling bottle machine was used instead of a bioreactor, leading to lower cost and no need for repeated sterilization during the whole process. The safe, effective and low-cost operation of successful production will provide a technical base for the large-scale preparation of lentivirus and thus lay a firm foundation for its clinical application.