title: Irradiated tumor cells of lipopolysaccharide stimulation elicit an enhanced anti-tumor immunity.
abstract: OBJECTIVE
  Lipopolysaccharide (LPS) is a major component of the outer surface membrane of Gram-negative bacteria which has been proved an effective immune enhancer. Here, we investigated the anti-tumor effect of irradiated tumor cells that stimulated by LPS in mouse xenografts models.
  
  
  METHODS
  Tumor cells were irradiated after stimulation with 1 μg/mL LPS for 48 h. The C57BL/6 mice were immunized subcutaneously with irradiated tumor cells. The anti-tumor effect of lymphocytes of immunized mice was investigated. The cytotoxicity of spleen lymphocytes from immunized mice was determined by a standard (51)Cr-release assay. The roles of immune cell subsets in anti-tumor activity were assessed by injected intraperitoneally with monoclonal antibodies.
  
  
  RESULTS
  We observed that the vaccine of irradiated tumor cell with LPS-stimulated elicited a stronger protective anti-tumor immunity than other controls. Adoptive transfer of lymphocytes of immunized mice showed that the cellular immune response was involved in the anti-tumor effect. And this effect was achieved by activation of antigen-specific CD8(+) T cell response and reduction of myeloid-derived suppressor cells (MDSCs, Gr1(+) CD11b (+) ), which were confirmed by depletion of immune cell subsets and flow cytometry analysis.
  
  
  CONCLUSIONS
  In summary, our study showed that stimulation of LPS was able to enhance anti-tumor immunity of vaccination with tumor cells after irradiation treatment, which might be a new strategy for cancer therapy.
authors.affiliation: State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Gaopeng Street, Keyuan Road 4, Chengdu, 610041, Sichuan, People's Republic of China.
authors.forename: Yuli
authors.initials: Y
authors.lastname: Li
authors.forename: Guobo
authors.initials: G
authors.lastname: Shen
authors.forename: Wen
authors.initials: W
authors.lastname: Nie
authors.forename: Zhimian
authors.initials: Z
authors.lastname: Li
authors.forename: Yaxiong
authors.initials: Y
authors.lastname: Sang
authors.forename: Binglan
authors.initials: B
authors.lastname: Zhang
authors.forename: Yuquan
authors.initials: Y
authors.lastname: Wei
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D019496:Cancer Vaccines / Q000008:administration & dosage / Q000276:immunology* / Q000528:radiation effects; D045744:Cell Line, Tumor; D005260:Female; D006825:Hybridomas; D016219:Immunotherapy, Adoptive; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008546:Melanoma, Experimental / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000276:immunology; D047368:Tumor Burden / Q000276:immunology; D014611:Vaccination; D023041:Xenograft Model Antitumor Assays
chemical_list: D019496:Cancer Vaccines; D008070:Lipopolysaccharides