Insect cells as a new substrate for vaccine production

Vaccine antigens can be expressed in several expression systems, of which expression in eukaryotic cell lines is a well-known example. Whereas for most current applications cell substrates such as Vero, MRC-5 or chicken embryo fibroblasts are used, cell lines derived from insects present an alternative for the future production of vaccines. Since such substrates are not yet extensively used, knowledge about their feasibility and safety for vaccine antigen production is limited. In the current example, an insect-derived cell line Hi-5, used for the expression of the human papilloma virus L1 antigen, was extensively characterized, in particular for aspects of viral safety. A comprehensive QC testing programme, complemented with additional characterization tests relevant to the insect nature of the cell line, was developed. Current results indicate the satisfactory quality and safety of the Hi-5 cell line. The proposed testing programme could stand as an example for the release testing and further characterization which would be required for insect cell lines.