title: Immune response to firefly luciferase as a naked DNA.
abstract: Firefly luciferase (Fluc) has been widely used as a reporter gene. The aim of this study was to investigate immune response to luciferase protein after an intradermal injection of pcDNA3.1-Fluc in immunocompetent BALB/c mice. We observed bioluminescence at injection sites from one to seven days post-injection when pcDNA3.1-Fluc was intradermally injected into ear-pinnae. To observe induced immune response, the percentages of CD8+IFNgamma+ cells in the draining lymphoid cells of immunocompetent BALB/c mice immunized by pcDNA3.1-Fluc were measured. And the tumor growths of CT26/Fluc in pcDNA3.1-Fluc group were monitored by observing bioluminescent signals and measuring tumor mass, and these were compared with those of the pcDNA3.1 group in immunocompetent BALB/c mice and immunodeficient Nu/Nu mice. In the immunocompetent BALB/c mice, percentages of CD8+IFNgamma+ cells in the pcDNA3.1-Fluc group were higher than those in the pcDNA3.1 group. Ten days after tumor inoculation, tumor growth inhibition was found in the pcDNA3.1-Fluc group, but not in the pcDNA3.1 group in the immunocompetent BALB/c mice. No significant difference in tumor growth inhibition was observed when CT26/Fluc was injected into immunodeficient Nu/Nu mice. In terms of cytokine profiles of draining lymphoid cells of immunized mice, IFNgamma protein levels in the pcDNA3.1-Fluc group were higher than in pcDNA3.1 group animals among the immunocompetent BALB/c mice. In conclusion, Fluc induced a Th1 immune response to Fluc protein delivered by injecting pcDNA3.1-Fluc into immunocompetent BALB/c mice. We suggest that immune response to the Fluc gene is cautionary in preclinical or clinical trials involving the Fluc gene, and that the immunologic potential of firefly luciferase as a naked DNA may be useful in cancer immunotherapy.
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Yong Hyun
authors.initials: YH
authors.lastname: Jeon
authors.forename: Yun
authors.initials: Y
authors.lastname: Choi
authors.forename: Joo Hyun
authors.initials: JH
authors.lastname: Kang
authors.forename: Chul Woo
authors.initials: CW
authors.lastname: Kim
authors.forename: Jae Min
authors.initials: JM
authors.lastname: Jeong
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Lee
authors.forename: June-Key
authors.initials: JK
authors.lastname: Chung
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology / Q000517:prevention & control; D000818:Animals; D000917:Antibody Formation; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003110:Colonic Neoplasms / Q000276:immunology / Q000473:pathology / Q000517:prevention & control*; D016207:Cytokines / Q000378:metabolism; D005260:Female; D049409:Luciferases, Firefly / Q000235:genetics*; D008198:Lymph Nodes / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology; D014407:Tumor Cells, Cultured; D014611:Vaccination; D019444:Vaccines, DNA / Q000276:immunology*
chemical_list: D016207:Cytokines; D019444:Vaccines, DNA; D049409:Luciferases, Firefly