Antitumor mechanism of recombinant murine interleukin-12 vaccine.
This study was designed to establish an interleukin-12 (IL-12)-expressing murine Lewis lung carcinoma (LLC) cell vaccine (LLC/murine IL-12 [mIL-12]) and assess its antitumor efficacy and mechanism in vivo. The recombinant IL-12 plasmid was transfected into LLC cells and screened by G418, and positive clones were obtained. C57BL/6 tumor-bearing mouse model was established and tumor-bearing mice were randomly divided into three groups (n = 20), that is, treated with an intratumoral injection of phosphate-buffered solution, blank plasmid, or LLC/mIL-12 vaccine, respectively, at days 0, 7, and 14. Tumor size was measured before and after treatment. Tumor growth curve was plotted, cytolytic T lymphocyte (CTL) activity assay and natural killer (NK) cell activity assay were performed, CD4(+) and CD8(+) T lymphocyte were quantitated using flow cytometry, and the expression of interferon-gamma (IFN-gamma), IL-12, and interferon-inducible protein-10 (IP-10) in serum was detected by ELISA. Microvessel density was determined by immunohistochemistry after all mice were euthanized at day 21. The study revealed suppressed tumor growth, elevated levels of IFN-gamma, IP-10, and IL-12, augmented NK and CTL cell activities, and decreased microvessel density of tumor tissues. There were abundant CD4(+) and CD8(+) T lymphocyte infiltration in the vaccine group. This study demonstrated that the antitumor mechanism of LLC/mIL-12 vaccine was to promote IFN-gamma and IL-12 secretion, augment the NK and CTL cell activities, and decrease the microvessel density of tumors.
Yin
Xiaoling
X
Department of Oncology, Southwest Hospital, Third Military Medical University, Chongqing, People's Republic of China.
Yan
Xuexian
X
Yang
Qinan
Q
Cao
Hui
H
Liang
Houjie
H
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D019496:Cancer Vaccines / Q000008:administration & dosage / Q000276:immunology / Q000627:therapeutic use*; D018827:Carcinoma, Lewis Lung / Q000098:blood supply / Q000276:immunology* / Q000473:pathology / Q000628:therapy*; D002452:Cell Count; D054357:Chemokine CXCL10 / Q000097:blood; D005260:Female; D007371:Interferon-gamma / Q000097:blood; D018664:Interleukin-12 / Q000097:blood / Q000235:genetics / Q000276:immunology* / Q000627:therapeutic use*; D007694:Killer Cells, Natural / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D055806:Microvessels / Q000473:pathology; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use*; D013154:Spleen / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology / Q000627:therapeutic use*
D019496:Cancer Vaccines; D054357:Chemokine CXCL10; D011994:Recombinant Proteins; D019444:Vaccines, DNA; D018664:Interleukin-12; D007371:Interferon-gamma