Abstract: Described is a process for generating a mammalian cell line from primary mammalian cells, comprising the step of: a) pre-treating a culture of said primary mammalian cells or a suspension thereof with at least one glucocorticoid, b) optional step comprising obtaining a suspension of said pre-treated culture of step a), c) transferring into the pre-treated cells of the suspension of step a) or b) at least one nucleic acid vector which is not of retroviral origin and which is competent to immortalize said pre-treated cells and d) culturing the transferred cells of step c). Furthermore, mammalian cell lines and cells obtainable by the described process are provided as well as pharmaceutical and diagnostic compositions containing such cells.

Abstract: Described is a human muscular cell line which is able to proliferate and generated from primary human muscular cells by a process comprising the step of: a) pre-treating a culture of said primary human muscular cells or a suspension thereof with at least one glucocorticoid, b) optional step comprising obtaining a suspension of said pre-treated culture of step a), c) transferring into the pre-treated cells of the suspension of step a) or b) at least one nucleic acid vector which is not of retroviral origin and which is competent to immortalize said pre-treated cells and d) culturing the transferred cells of step c). Furthermore, human muscular cells derived from said cell lines are provided as well as pharmaceutical and diagnostic compositions comprising the same.

Abstract: Cell lines have been prepared from transgenic mice comprised of a first exogenous DNA sequence encoding human factor IX which is controlled by a promoter region specific for hepatic cells and a second exogenous DNA sequence encoding an oncogene, such as the SV40 virus gene encoding the T-antigen or the mouse c-myc gene, which is controlled by a promoter region specific for hepatic cells. Promoter regions specific for hepatic cells included the promoter region for the factor IX gene and the promoter region for the .alpha.-1 antitrypsin gene. The cultured cells produce biologically active human factor IX which is then isolated from the culture media.