Sf9 Cells

Sf9 cells are clonal isolates derived from the Spodoptera frugiperda Sf21 cell line (IPLB-Sf-21-AE). They are commonly used in insect cell culture for recombinant protein production using baculovirus expression systems. Sf9 cells are epithelial in morphology and were cloned from the pupal ovarian tissue of the fall armyworm. One of the key characteristics of Sf9 cells is their small, regular size which is ideal for the formation of monolayers and plaques. They are also suitable for transfection, plaque assay/purification, amplification of high-titer stocks, and expression of recombinant proteins. The Sf9 insect cell line can be maintained in attached and suspended cultures, and do not require serum or CO2 to grow. They are considered Biosafety Level 1 and are usually grown in a 26-28 degree celsius incubator. Sf9 cells/baculovirus expression systems are widely used for high-level protein expression, often for purification, but proteins may also be functionally expressed in the defined Sf9 cell environment. The size of infected Sf9 cells is generally 17-30 microns in diameter. The Sf9 cell line is distinct from the Sf21 cell line in that it is a clonal isolate with a smaller and more regular size, while Sf21 cells are more disparate in size and form monolayers and plaques that are more irregular. Some Sf9 cell lines may harbor a negative sense Rhabdovirus called Spodoptera frugiperda rhabdovirus (SfRV), although not all tested Sf9 cells appear to be infected with this virus. The genome size of Sf9 has been estimated to be 451 Mbp with a G+C content of 36.53%.