| 2 | Expression of co-stimulator 4-1BB molecule in hepatocellular carcinoma and adjacent non-tumor liver tissue,and its possible role in tumor immunity显示文摘AIM:To investigate the expression of 4-1BB molecule in hepatocellular carcinoma (HCC) and its adjacent tissues.METHODS:Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the gene expression of 4-1BB in hepatocarcinoma and its adjacent tissues,and peripheral blood mononuclear cells (PBMCs) from both HCC and health control groups.Flow cytometry was used to analyse the phenotypes of T cell subsets from the blood of HCC patients and healthy volunteers,and further to determine whether 4-1BB molecules were also expressed on the surface of CD4+ and CD8+ T cells. The localization of 4-1BB proteins on tumor infiltrating T cells was determined by direct immunofluorescence cytochemical staining and detected by confocal microscopy.RESULTS:4-1BB mRNA, which was not detectable in normal liver,was found in 19 liver tissues adjacent to tumor edge(<1.0cm).Low expression of 4-1BB mRNA was shown in 8 tumor tissues and 6 liver tissues located within 1 to 5cm away from tumor edge. In PBMCs, 4-1BB mRNA was almost not detected. Percentage of CD4^+, CD8^+ and CD3^+/CD25^+ T cells, as well as ratio of CD4 to CD8 revealed no difference between groups (P>0.05,respectively),while a significant lower percentage of CD3^+ T cell was found in HCC group as compared to healthy control group (P<0.05).However, 4-1BB molecules were almost not found on the surface of CD4+ and CD8+ T cells in HCC and healthy control group.Double-staining of 4-1BB^+/CD4^+ and 4-1BB^+/CD8^+ immunofluorescence on tumor infiltrating T cells was detected in 13 liver tissues adjacent to tumor edge (<1.0cm) by confocal microscopy.CONCLUSION: Although HCC may escape from immune attack by weak immunogenicity or downregulated expression of MHC-1 molecules on the tumor cell surface,tumor infiltrating T cells can be activated via other costimulatory signal pathways to exert a limited antitumor effect on local microenvironment. The present study also implicates that modulating 4-1BB/4-1BBL costimulatory pathway may be an effective immunotherapy strategy to augment the host response. | Wan, YL Zheng, SS Zhao, ZC Li, MW Jia, CK Zhang, H | 2004 | World Journal of Gastroenterology2004，10，2： | 6 |
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