Irradiated tumor cells of lipopolysaccharide stimulation elicit an enhanced anti-tumor immunity.
J Cancer Res Clin Oncol 2014;
140:1815-23. [PMID:
24927808 DOI:
10.1007/s00432-014-1721-4]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 05/22/2014] [Indexed: 02/07/2023]
Abstract
PURPOSE
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.
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