Effect of serum type and concentration on the expression of beta-galactosidase in recombinant vaccinia virus infected HeLa S3 cells

The effect of serum type and concentration on recombinant protein expression in vaccinia virus infected HeLa S3 cells was studied in both static and suspension culture. A model heterologous protein, beta-galactosidase (beta-gal), was used. Calf and horse sera in the range of 0.5-10%(v/v) were investigated. In static culture, the calf serum concentration did not show any significant influence on the beta-gal production which was almost completed within 24 h postinfection (pi). Higher horse serum concentration, on the other hand, resulted in higher beta-gal concentration which continued to increase until 48 h pi. Total beta-gal concentrations in 0.5% calf serum at 24 h pi and 10% horse serum at 48 h pi were 2.2 +/- 0.7 and 2.2 +/- 0.1 IU/ml, respectively. In suspension culture, both sera showed their respective effects on the beta-gal production similar to those observed in static culture, indicating that the cultivation method had little influence on beta-gal production. Accordingly, the use of 0.5% calf serum after virus infection is recommended for economical beta-gal production.