[Changes of regulatory T cell number in hepatocellular carcinoma-bearing mice and its relationship with tumor growth].
OBJECTIVE
To study the relationship between the change of regulatory T cell number in CD4+ T subset and the growth of tumor in H22 hepatocellular carcinoma-bearing mice.


METHODS
Tumor-bearing mice were established by subcutaneous inoculation of H22 hepatocelluler carcinoma cells. Flow cytometry was used to detect the expression of CD4 and CD25 molecules of the T cells which came from the tumor-bearing mice. The Foxp3 gene expression was detected by RT-PCR and flow cytometry. CD4+ CD25+ T cells and CD4+ CD25- T cells were separated and purified by immuno-magnetic beads. The proliferation and suppressive function of the CD4+ CD25+ T cells coming from tumor-bearing mice was measured by [3H]-thymidines incorporation experiment in vitro, and then effect of CD4+ CD25+ T cells originated from hepatocellular carcinoma-bearing mice on tumor growth was observed in vivo.


RESULTS
(1) Compared with mice of the control group, the percentage of CD4+ CD25+ T cells of CD4+ T cells in tumor-bearing mice is not only higher in draining lymph nodes (18.80% < or = 0.06%) vs. (9.50% +/- 0.03%), (P < 0.01), but also higher in non-draining lymph nodes (LN) and spleen (SP), LN: (16.28% +/- 0.02%) vs. (9.50% +/- 0.03%), P < 0.01; SP: (17.28% +/- 0.06%) vs. (11.08% +/- 0.04%), (P < 0.05). The expression of regulatory T cell specific marker Foxp3 gene was also increased. In the same tumor-bearing mice, the number of CD4+ CD25+ T cells in draining lymph node was relatively higher than the contralateral nondraining lymph node, but the difference was statistically not significant (18.8% +/- 0.06%) vs. (16.28% +/- 0.02%), (P > 0.05). (2) The CD4+ CD25+ T cells purified from tumor-bearing mice--like naturally occurring regulatory T cells--were anergic to anti-CD3 monoclonal antibody stimulation in vitro, but it could suppress CD4+ CD25- T cells proliferation. (3) The percentage of CD4+ CD25+ T cells was positively related to tumor size. It could also suppress the anti-tumor effect of CD4+ CD25- T cells in vivo. Conclusion The growth of hepatocellular carcinoma in mice can boost the amount of regulatory T cells. The amount of regulatory T cells is positively related to tumor size, indicating that attack on regulatory T cells could be used as one of modalities in cancer treatment in the future.
Zhang
Pin
P
Institute of Immunology, Medical School of Shandong University, Jinan 250012, China.
Zhang
Li-ning
LN
Zhu
Fa-liang
FL
Wang
Qun
Q
Wang
Xiao-yan
XY
Li
Hai-yan
HY
Liu
Chun-mei
CM
Gao
Fei
F
Liu
Cheng-hu
CH
D000818:Animals; D015704:CD4 Antigens / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005260:Female; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology; D008113:Liver Neoplasms / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D008114:Liver Neoplasms, Experimental / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D008198:Lymph Nodes / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013154:Spleen / Q000276:immunology / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology* / Q000378:metabolism
D015704:CD4 Antigens; D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D053645:Interleukin-2 Receptor alpha Subunit