Various methods for the growth of insect cells and the production of recombinant human beta-interferon (rHu beta-IFN) by insects cells, Spodoptera frugiperda, IPL-Sf-21AE after infection with recombinant AcNPV are described. Using a suspension perfusion Biospin filter culture system, an IPL-Sf-21AE cell line was propagated in a semi-controlled environment. To obtain and maintain high cell densities and viabilities in this system, the culture medium for suspension methods was modified by supplementing with ZnSO4, ALCl3, methyl cellulose and Darvan #2. Using these improved conditions, multiple harvests of rHu beta-IFN were collected in the cell culture supernatant for downstream processing.