Effects of cytotoxic T lymphocytes on hepatoma cell line SMMC-7721 induced by different subsets of dendritic cells in vitro.
BACKGROUND
Dendritic cells (DCs) loaded with complex antigen are always used to induce cytotoxic T lymphocytes (CTLs) which have a specific anti-tumor activity. However, CTLs can assault autologous cells induced by DCs loaded with autologous antigen. This study aimed to explore how to weaken the autoimmune reaction induced by DC vaccine by combining mature DC (mDC) activating immunity and immature DC (imDC) leading to immune tolerance to make hepatocellular carcinoma (HCC) vaccine in vitro.


METHODS
DC progenitors derived from human peripheral blood were assigned to two groups. One was cultured to mDC and pulsed with frozen-thawed antigen (FTA) of human HCC cell line SMMC-7721 cells (mDC group), and the other was cultured to imDC and pulsed with FTA of human liver cell line L-02 cells (imDC group). The morphology of DCs was monitored and cells phenotypes including HLA-DR, CD80, CD1alpha, CD83 were assayed by flowcytometry (FCM). The concentrations of interleukin-12 (IL-12) in the supernatant were assayed by ELISA. Methyl thiazolyl tetrazolium (MTT) was used to evaluate T cell proliferation induced by mDC and imDC and the killing rate of CTL induced by mDC and imDC respectively/together on SMMC-7721 and L-02 cells.


RESULTS
Compared with the imDC group, the mDC group was characterized by the following: increased secretion of IL-12 (P<0.05); higher expression of HLA-DR, CD1alpha, CD80, CD83; and stronger activity in stimulating proliferation of isogenic T cells (P<0.05). CTL induced by the mDC group had a significant killing response to SMMC-7721 as well as a higher killing rate for L-02 (P>0.05). CTL induced by mDC and imDC together had a higher killing response to SMMC-7721, but a lower killing rate for L-02 (P<0.01).


CONCLUSIONS
CTL induced by mDC and imDC together has a higher antigen-specific killing response in vitro than that induced by mDC alone. This may be of greater clinical value.
Wang
Jia-Xiang
JX
Department of Surgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China. wjiaxiang@zzu.edu.cn
Liu
Guang-Hui
GH
Fan
Ying-Zhong
YZ
Liu
Qiu-Liang
QL
Zhou
Juan
J
Zhang
Dong-Yun
DY
Qi
Yuan-Ming
YM
D006528:Carcinoma, Hepatocellular / Q000276:immunology*; D045744:Cell Line, Tumor; D003713:Dendritic Cells / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D066298:In Vitro Techniques; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*