Protein Sciences Makes Proprietary Serum-Free High-Density Insect Cells Available to Researchers

Protein Sciences Corp. (Meridian, CT) is making its proprietary expresSF+ serum-free high-density insect cells available for research and cGMP production of recombinant proteins, the company announced last week. The expresSF+ cell line, which is used with the baculovirus expression vector system, is the first insect cell line commercially available to scientists that is derived from Master and Working Cells Banks.

Gale Smith, chief scientific officer of Protein Sciences and co-inventor of the baculovirus expression vector system, stated, "The expresSF+ cells are a truly serum-free, stable, high-yielding, and safe source of recombinant proteins for research and clinical development. They have important advantages as compared to widely used and commercially available cell lines such as S. frugiperda Sf9 and T. ni High Five."

Veronica Moreno, a scientist at the R.F. Johnson Research Institute and one of the first purchasers of expresSF+ cells, reported "two- to three-fold higher expression compared to other cells" during a presentation at the BIO meeting in May 1999.

Insect expression systems offer advantages over expression systems, both prokaryotic and eukaryotic. Being eukaryotes, insect cells are able to cleave, process, and fold proteins correctly. However, they are easier and less expensive to maintain than mammalian cells, since they grow at room temperature and do not require CO₂ for growth. In addition, the BEV system expresses proteins at high levels, can accommodate large proteins, and can express more than one protein at a time. In clinical studies, proteins made in BEV systems have proven safe for administration to humans.

Protein Sciences is making its Serum Free expresSF+ cells and its High Density expresSF+ cells available. As provided, they meet current FDA standards for identity and stability; they are free of contaminating mycoplasma, spiroplasma, and other adventitious organisms; and are non-tumorigenic in nude mice.

Serum Free expresSF+ cells are free of exposure to serum, including during storage; and they double about every 24 hours in commercial serum-free media. They yield 10⁷ or more cells/ml with nearly 100% viability in standard suspension cultures. Unlike other serum-free insect cells, expresSF+ cells also generate high titers of baculovirus, so a single cell line can be used for the production of recombinant baculoviruses and proteins.

High Density expresSF+ cells grow to 10⁸ cells/ml and recombinant protein production can be done at more than 10⁷ cells/ml in a proprietary high density bioreactor process developed and optimized for expresSF+ cells at Protein Sciences.

Founded in 1983, Protein Sciences Corp. is a biopharmaceutical service and product development company that focuses on the commercial production of protein-based human and veterinary vaccines and therapeutic proteins using BEV technology. The company's principal business is developing such vaccines and therapeutics as a service for customers through GeneXpress. This program enables customers to access Protein Sciences' proprietary BEVS technology to produce human and animal proteins for drug screening and clinical trials.

For more information: Manon J.J. Cox, Protein Sciences Corp., 1000 Research Parkway, Meriden, CT 06450. Tel: 203-686-0800, Ext. 308.