Development of Serum-Free Media for Lepidopteran Insect Cell Lines

Abstract

Lepidopteran insect cell culture technology has progressed to the point of becoming an essential part of one of the most successful eukaryotic expression systems and is increasingly used industrially on a large scale. Therefore, there is a constant need for convenient and low-cost culture media capable of supporting good insect cell growth and ensuring high yield of baculovirus as well as the strong expression of recombinant proteins. Vertebrate sera or invertebrate hemolymph were essential supplements in first-generation insect cell media. These supplements, however, are cumbersome and expensive for routine large-scale culture; thus, their use is now circumvented by substituting the essential growth factors present in these supplements with serum-free substances. Such non-serum supplements are typically of non-animal origin and include protein hydrolysates, lipid emulsions, and specialized substances (e.g., surfactants and shear damage protecting chemicals). These supplements need to complement the defined, synthetic basal medium to ensure that the fundamental nutritional needs of the cells are satisfied. Although there is a significant number of proprietary serum-free and low-protein or protein-free media on the market, the lack of information concerning their detailed composition is a drawback in their adoption for different applications, including their adaptation to the metabolic and kinetic analysis and monitoring of a given insect cell based bioprocess. Hence, there is wide appeal for formulating serum-free media based on a rational assessment of the metabolic requirements of the lepidopteran cells during both the growth and the production phases. Techniques such as statistical experimental design and genetic algorithms adapted to the cellular behavior and the bioreactor operation mode (batch, fed-batch, or perfusion) permit the formulation of versatile serum- and protein-free media. These techniques are illustrated with recent developments of serum-free media for the cultivation of commercially important Spodoptera frugiperda and Trichoplusia ni cell lines.

Development of a simple and high-yielding fed-batch process for the production of porcine circovirus type 2 virus-like particle subunit vaccine

“…It is maybe that the synthesis of the cell membrane was disrupted in the cells. Indeed, insect cells have incomplete lipid metabolism (Agathos 2007) and need lipid supplementation. The lipids in the initial medium may not be sufficient for high cell densities.…”

Serum-Free Culture of the Suspension Cell Line QB-Tn9-4s of the Cabbage Looper,Trichoplusia ni, is Highly Productive for Virus Replication and Recombinant Protein Expression

“…In insect cell cultures, serum provides not only growth factors for cell growth and reproduction but also detoxifying and antioxidant proteins and protease inhibitors for cell protection (Agathos 2007). In the adaption process of QB-Tn9-4s cells to serum-free medium, with reduction of serum concentration, cells were prone to aggregate, form many particles around areas with high cell density, and grow slowly.…”

“…However, serum is expensive and contains complex components detrimental to separation, purification, and detection of culture products, limiting the application of insect cells. Thus, developing serum-free cultures of insect cell lines is desirable in cell, genetic, and protein engineering, medical biology, biotechnology, and the production of baculovirus and recombinant proteins (Agathos 2007;Hashimoto et al 2010). A variety of insect cell lines have been successfully cultured in serum-free media (Ikonomou et al 2002;Lua et al 2003;Imanishi et al 2012).…”

Quality Control of Baculoviral Bioinsecticide Production

“…Other problems are related to the composition of culture media and the availability of susceptible insect cell lines to each baculovirus. Actually, many researchers are working on the establishment of new cell lines or modifying existing ones to improve their performance, while others have focused on developing proper and cheaper formulations of growth media for cell propagation in vitro (Agathos, 2007;Micheloud et al, 2009). …”