Abstract: On the new findings that cyclodextrin shows no cytotoxicity or only slight cytotoxicity on cell growth and that lipophilic substances such as unsaturated fatty acids and lipophilic vitamins when present together with, or included in, cyclodextrin show such effects as cell growth promoting effect and accelerating effect of the productivity of valuable products, a serum-free or serum-reduced culture medium or a substitute composition for serum for a culture medium comprising a cyclodextrin and at least one lipophilic nutrient substance, said cyclodextrin and said lipophilic nutrient substance being preferably in the form of inclusion complex between them, is provided.

Abstract: Process for preparing a continuous and spontaneous human-interferon-producing lymphoblastoid cell line which involves (a) transforming human lymphocytes isolated from a human infant from birth up to about 2 years or an aborted human fetus, the transforming being carried out with Epstein Barr Virus and (b) selecting from the resulting transformed cell lines a cell line producing more than 1000 units of interferon per milliliter when cultivated at a cell density of 10.sup.6 cells per milliliter in the absence of any interferon inducer.

Abstract: Immobilized biologically active proteins such as enzymes having high activity and stability are prepared by covalent bonding of the biologically active protein to an azide derivative of a polypeptide such as polymethylglutamate of which at least one carboxyl group in a side chain is converted to a carboxyl azide group.