VARIATION IN RECOMBINANT PROTEIN EXPRESSION LEVELS AMONG CLONES OF LEPIDOPTERAN CELL-POPULATIONS

Clones isolated from the heterogenous Spodoptera frugiperda IPLB-Sf-21 -AE and Mamestra brassiace IZD-Mb-O503 insect cell populations have be en compared in regards to their synthesis of recombinant Escherichia c oli beta-galactosidase (beta-gal), human tissue plasminogen activator (t-PA), and human kidney renin. Significant differences were found amo ng the clones in their expression levels of these proteins. In additio n, the expression levels of t-PA and renin were considerably less than that of beta-gal. Clone BC5 was the best producer of t-PA and renin a mong the Mb-O503 clones, whereas clone BB5 was the best producer of be ta-gal. The Sf-9 cell line and clone 2 were the best producers of t-PA and renin, respectively, among the Sf-21 clones. The Mb-O503 clones g enerally were better producers of t-PA than the Sf-21 clones, with the BC5 clone producing twice the levels of any other Mb-O503 or Sf-21 cl one. The Sf-21 clones were generally better renin producers; the Mb-O5 03 clones were generally found to have beta-gal expression levels supe rior to those reported previously for the Sf-21 clones.