title: Efficient systemic expression of bioactive IL-15 in mice upon delivery of optimized DNA expression plasmids.
abstract: Efficient expression vectors for interleukin 15 (IL-15) were developed combining RNA/codon optimization and modification of the IL-15 native long signal peptide. These changes resulted in elevated cytoplasmic levels of the optimized mRNA and more than 100-fold improved production of secreted human IL-15 protein. Similar modifications have also led to greatly increased rhesus macaque and murine IL-15 production. Comparison of different heterologous secretory signals showed that the tissue plasminogen activator signal is most efficient for the production of extracellular IL-15. Upon intramuscular injection of the fully optimized expression vectors in mice, IL-15 was readily detected in the serum. Serum levels represented <1% of intramuscular IL-15 and were sufficient in causing some systemic effects, such as increasing the frequency of natural killer (NK) cells in the liver. Upon hydrodynamic DNA delivery in mice, very high levels of IL-15 were produced, which increased the frequency of NK cells in liver as well as in spleen and lung. These optimized expression vectors have potential applications in vaccine and immunotherapy approaches against AIDS and cancer.
authors.affiliation: Human Retrovirus Pathogenesis Section, Vaccine Branch, National Cancer Institute-Frederick, Frederick, Maryland 21702-1201, USA. felber@ncifcrf.gov
authors.forename: Rashmi
authors.initials: R
authors.lastname: Jalah
authors.forename: Margherita
authors.initials: M
authors.lastname: Rosati
authors.forename: Viraj
authors.initials: V
authors.lastname: Kulkarni
authors.forename: Vainav
authors.initials: V
authors.lastname: Patel
authors.forename: Cristina
authors.initials: C
authors.lastname: Bergamaschi
authors.forename: Antonio
authors.initials: A
authors.lastname: Valentin
authors.forename: Gen-Mu
authors.initials: GM
authors.lastname: Zhang
authors.forename: Maninder K
authors.initials: MK
authors.lastname: Sidhu
authors.forename: John H
authors.initials: JH
authors.lastname: Eldridge
authors.forename: David B
authors.initials: DB
authors.lastname: Weiner
authors.forename: George N
authors.initials: GN
authors.lastname: Pavlakis
authors.forename: Barbara K
authors.initials: BK
authors.lastname: Felber
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005260:Female; D015870:Gene Expression; D005822:Genetic Vectors; D006801:Humans; D019409:Interleukin-15 / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics*; D008253:Macaca mulatta; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009132:Muscles / Q000378:metabolism; D010957:Plasmids / Q000008:administration & dosage / Q000235:genetics; D021382:Protein Sorting Signals / Q000235:genetics; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000097:blood / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D019409:Interleukin-15; D021382:Protein Sorting Signals; D012333:RNA, Messenger; D011994:Recombinant Proteins