QMCF Technology is an episomal protein expression system that uses genetically modified mammalian cells and specially designed plasmids. QMCF plasmids carry a combination of regulatory sequences from mouse polyomavirus (Py) DNA replication origin which in combination with Epstein-Barr virus (EBV) EBNA-1 protein binding site as nuclear retention elements ensure stable propagation of plasmids in mammalian cells. In addition the vetors carry the selection marker operational for selection of plasmid carrying bacteria and QMCF cells, bacterial ColE1 origin of replication, and cassette for expression of protein of interest. QMCF cell lines express Large-T antigen and EBNA-1 proteins which bind the viral sequnces on the QMCF plasmid and hence support plasmid replication and maintenance in the cells. QMCF Technology has several important differences compared to commonly known transient expression and stable cell line expression systems. Unlike in transient expression system, QMCF Technology enables to maintain episomally replicating QMCF plasmids inside the cells for up to 50 days thus providing an option for production phase of 2–3 weeks. Therefore the production levels of QMCF Technology are higher (up to 1g/L). Another difference is the option of establishing expression cell banks within one week, which is not feasible with transient system. Compared to usage of stable cell line, QMCF technology is a rapid method leaving out time-consuming clone selection step during cell line development.
QMCF Technology can be used for: