COMPARATIVE RECOMBINANT PROTEIN-PRODUCTION OF 8 INSECT-CELL LINES

A recombinant Autographa californica baculovirus expressing secreted a lkaline phosphatase (SEAP) gene was used to evaluate the expression of a secreted glycoprotein in eight insect cell lines derived from Spodo ptera frugiperda, Trichoplusia ni, Mamestra brassicae and Estigmene ac rea. Because cell density was found to influence protein production, S EAP production was evaluated at optimal cell densities for each cell l ine on both a per cell and per milliliter basis. On a per cell basis, the T. ni-derived BTI-TN-5Bl-4 cells produced a minimum of 20-fold mor e SEAP than the S. frugiperda-derived Sf9 or Sf21 cell lines and a min imum of 9-fold more than any of the other cell lines growing in serum- containing medium. On a per milliliter basis, BTI-TN-5Bl-4 cells produ ced a minimum of fivefold more SEAP than any of the other cell lines t ested. Using cell lines that were adapted to serum-free medium, SEAP y ields were the same or better than their counterparts in serum-contain ing medium. At 3 days postinoculation, extraeellular SEAP activity ran ged from 59 to 85% of total SEAP activity with cell lines grown in ser um-free and serum-containing media.