Sf -9 insect is an immortalized cell line derived from ovarian cells of Spodoptera frugiperda, a moth (moth ), the family of the cutworms ( Noctuidae ) and the order of the butterflies (Lepidoptera ) counts. This is used in biotechnology for the production of recombinant proteins.
Sf -9 cells derived from the ovarian tissue of Spodoptera frugiperda, taken during the pupal stage. This was done via an intermediate cultivation of IPLB - Sf21AE cell line. From a clone, that is, the descendants of a cell IPLB - Sf21AE Sf -9 cells were isolated.
The Sf -9 cells are robust, low shear stress- sensitive cells growing adherent and in suspension. Their optimal cultivation temperature is 27 ° C, with an optimum pH of 6.2. They can be good in serum- free media cultivate, one of which is contained by about ten times higher amino acid concentration than comparable media for mammalian cells in general.
W. F. Hink of The Ohio State University in 1991, a serum-free medium developed, can be cultivated with the Sf -9 cells and in the production of recombinant proteins succeed just as well as in cultures that are tightened with the usual serum-containing medium.
Sf -9 ( and related cells, such as Sf -21) and Tn -5 ( BTI -Tn - 5B1 accurate -4, also High Five ®) from Trichoplusia ni are now almost exclusively used for the production of recombinant proteins. It makes use of the fact that these cells can be easily with baculoviruses (eg AcMNPV ) infected. The genome of the virus can be relatively easily modified so that it encodes the desired protein (usually under control of the viral polyhedrin promoter ). After infection of Sf9 cells with this virus, the cells are stimulated to synthesize large quantities of the recombinant protein. Since the modified viruses are harmless to higher eukaryotes, these operations can be carried out under relatively low safety precautions. Further advantages over other expression systems, are:
- Perform differently from E. coli and yeast by almost all post-translational protein modifications, that is, the recovered proteins are very similar to human
- Thus the proteins almost always have a very good solubility (in contrast to recombinant proteins from E. coli, which are often insoluble, since this bacterium can not perform a man comparable post-translational modifications and continues to hold a very simple chaperone )