Immune Suppression Substance Secreted By HepG2 Cell Line

Purpose: Interactions between the immune system and malignant cells play an important role in tumor genesis. Failure of the immune system to detect and reject transformed cells may lead to cancer development. Tumors use multiple mechanisms to escape from immune-mediated rejection. Many of these mechanisms are now known on a cellular and molecular level. Despite this knowledge, cancer immunotherapy is still not an established treatment in the clinic. The purpose of this study is to find some new immune escape mechanisms used by tumors. Methods: Pre-collected supernatant of HepG2 cell line and control cell line were added to activated lymphocyte for 72 h, proliferation was measured by 3H-thymidine incorporation.Results: In contrast to activated lymphocyte, supernatant of HepG2 cell line exhibited the capacity of inhibiting the proliferation of lymphocyte. Assessment of proliferation revealed a classical dose-response inhibition of lymphocyte proliferation caused by the HepG2 cell line -derived supernatant, On the other hand, control supernatant failed to show significant inhibitory effects. We have illustrated that there were many kinds of protein, which were bigger than 100KD, works as inhibitors in the supernatant of HepG2 cell line. Especially, we have investigated that exosome which was secreted by HepG2 cell line could inhibit T-cell proliferation, Conclusions: HepG2 cell line could secret many kinds of proteins which exhibited the capacity of inhibiting T-cell proliferation, and this is probably responsible for tumors immune escape.