Insect Cell Culture
Insects are the vectors for a large number of viruses causing diseases on economic plants as well as animals including humans. Some important diseases are also caused by certain insects such as Aedes aegypti for yellow fever, Anopheles female for malaria, Bombax mori for silk disease, Heliothis zea cotton boll, etc.
Insect cells are grown in suspension in suitable bioreactor. The bioprocess technology developed for certain mammalian cell is also applicable for insect cells with certain alterations. The physicochemical factors affecting cell expression for production of valuable products are cell viability, cell density, insect species, types of tissue, concentration of dissolved O2, composition of culture medium, property of cell attachment and nature of substratum (Agathos, 1991).
Significant achievement gained in the area of health care and agriculture has focussed the attention of biotechnologists in recent years. Cultures of insect cells have become a good tool for expression of heterologous gene products (Table 6.7). Baculoviruses infect only invertebrates, but neither vertebrates nor humans nor plants. Genetically modified vector expression in cultured insect cells and expression of foreign genes if introduced into cells for the production of biotechnological products viz., recombinant proteins and viral insecticides, cell culture of certain insects (such as moths, flies, butterflies, mosquitoes, bollworms, loopers, etc) are being used-Nuclear polyhedrosis viruses (NPVs) are the most widely used baculoviruses. The NPVs consist of double stranded DNA. They are the natural pathogens of the insects of the group Lepidoptera. Therefore, they grow well in cell cultures of members of Lepidoptera (Agathos, 1991).