title: Expression of amplified cDNA and genomic sequences encoding human interleukin 2 in Chinese hamster ovary cells.
abstract: Expression of human interleukin 2 (IL-2) at high levels has been achieved in Chinese hamster ovary (CHO) cells by amplification of transfected sequences. Plasmids containing the human IL-2 cDNA or genomic DNA and mouse dihydrofolate reductase (DHFR) cDNA were transfected into DHFR-negative CHO cells. Transformants expressing DHFR were selected in media lacking nucleosides, and cells which amplified both DHFR and IL-2 genes were obtained by exposure to increasing methotrexate (MTX) concentrations. These cell lines constitutively expressed elevated levels of IL-2 at a concentration of 2 mg/liter. These cell lines continued to produce IL-2 stably through at least 1 month, even in the absence of MTX.
authors.affiliation: Central Research Laboratories, Ajinomoto Co., Inc., Kanagawa.
authors.forename: K
authors.initials: K
authors.lastname: Onomichi
authors.forename: Y
authors.initials: Y
authors.lastname: Eto
authors.forename: H
authors.initials: H
authors.lastname: Shibai
mesh_terms: D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA / Q000378:metabolism; D004262:DNA Restriction Enzymes; D005260:Female; D005784:Gene Amplification; D005796:Genes; D006801:Humans; D007376:Interleukin-2 / Q000235:genetics*; D008727:Methotrexate / Q000494:pharmacology; D010053:Ovary; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D007376:Interleukin-2; D004247:DNA; D013762:Tetrahydrofolate Dehydrogenase; D004262:DNA Restriction Enzymes; D008727:Methotrexate