INSECT-CELL LINE DEPENDENT GENE-EXPRESSION OF RECOMBINANT HUMAN TUMORNECROSIS FACTOR-BETA

The expression and secretion of recombinant human tumor necrosis facto r-beta (TNF-beta lymphotoxin) was examined in seven different insect h ost cell lines, namely, Spodoptera frugiperda (Sf) 9-ATCC, Sf9-IXP, Sf 21, Trichoplusia ni (BTI-TN-5B1-4), Mamestra brassicae (IZD-MB-0503), IPLB-HZ1075, and Antheraea moth ovarian cells. The highest yield of se creted recombinant human TNF-beta was obtained by using the Sf21 cells ; the maximum protein productivity achieved was 71.7 mu g 1(-1) x 10(6 ) Sf21 cells. This is an increase of 100% over the yields obtained fro m the Sf9-ATCC cells. In addition, a new cell clone, Sf9-IXP, was deri ved which was larger in cell volume and had a 76% higher TNF-beta expr ession and secretion in comparison to the native original Sf9 cells. S f9-ATCC cells infected with recombinant baculoviruses secreted TNF-bet a at 32.1 mu g 1(-1) x 10(6) cells. The lowest productivity was seen f or IPLB-HZ1075 cells which attained 7 mu g 1(-1) x 10(6) cells. There is a proportional relationship between increased protein production an d the increase in cell volume and granularity. Recombinant protein exp ression and secretion was also shown to be influenced by the intracell ular metabolic activities of the cells and it was observed that the re combinant human TNF-beta expressed and secreted by the different insec t cells has the same molecular weight.