OPTIMIZATION OF THE PRODUCTION OF FULL-LENGTH RCD4 IN BACULOVIRUS-INFECTED SF9 CELLS

The baculovirus-insect cell system is reliable in expressing a variety of recombinant proteins. A recombinant baculovirus encoding the full length human CD4 has been used to infect Spodoptera frugiperda 9 cells in 6-L-airlift fermentors. The procedures described in this report permitted a 6.5-fold enhancement of rCD4 expression as compared to standard procedures previously published. The increase of rCD4 expression on the cell surface was achieved by using the following steps: (1) Optimal seeding density of 0.8 x 10(6) cells/mL used to multiply cells at a maximum exponential growth of 4.5 x 10(6) ; (2) high multiplicity of infection (MOI) of 580 PFU/cell; (3) addition of medium at time of infection. In addition to full-length rCD4, a "short" rCD4 with largely deleted cytoplasmic sequence (last 31 C-terminal amino acids) was also efficiently expressed.