[Effects of ovarian carcinoma cells on the maturation and function of human dendritic cells]

To investigate the effects of ovarian carcinoma cells on the differentiation, maturation, and function of the dendritic cells (DC).

Human epithelial ovarian carcinoma cells were isolated from specimens of ovarian carcinoma from 12 patients obtained during operation, and cultured. Peripheral blood samples were collected from these patients. DC were isolated and co-cultured with recombinant human tumor necrosis factor (TNF)-alpha to promote their maturation. Immunostaining and flow cytometry (FC) were used to detect the DC specific marker CD1a, maturation marker CD83, co-stimulating factors CD86 and human leucocyte antigen (HLA)-DR. FITC-labeled glucan was added and FC was used to detect the phagocytic function. T cells were co-cultured with immature and mature DC of different concentrations respectively for 96 h, 18 h before the end of culture 3H-TdR was added, liquid scintillation counter was used to measure the level of count per minute (cpm) Ovarian carcinoma cells and peripheral mononuclear cells were put into Transwell to contact each other directly or indirectly, TNF-alpha was add to promote the maturation, and then FC was used to detect the CD1a, CD83, CD86, and HLA-DR levels, and the glucan uptake level. ELISA was used to detect the levels of IL-12, IL-10, and interferon (IFN)-gamma, and Western blotting was used to detect the p-38 protein and phosphorylated p-38 protein in the supernatant.

After stimulation of TNF-alpha the expression; levels of CD1a, CD86, CD83, and HLA-DR of the DCs were remarkably increased. Immature DCs showed a strong ability at phagocytosis of glucan, and this ability was decreased by the stimulation of TNF-alpha. The proliferative function of mature DCs on allogenic T lymphocytes was significantly increased dose-dependently (P<0.05). Co-culture with ovarian carcinoma cells decreased the expression levels of CD1a, CD86, and HLA-DR, increased the expression level of CD83, and decreased the ability in up taking glucan by 43.05%. The proliferative function of the DC cultured in direct contact with ovarian carcinoma cells was decreased by 56.35%, and such inhibitory function of the DCs cultured not in direct contact with ovarian carcinoma cells was weaker, and the levels of CD1a, CD86, CD83, and HLA-DR expressed by the DC cultured not in direct contact with ovarian carcinoma cells was between those of the DC cultured in direct contact with ovarian carcinoma cells and those of the DC undergoing routine culture. The levels of IL-12 and phosphorylated p-38 protein were decreased in the supernatant of the DC co-cultured with ovarian carcinoma cells.

Ovarian carcinoma cells suppress the differentiation of monocyte into DC, negatively regulates the phagocytotic and antaean managing functions of DC, thus the DC can not effectively stimulate the proliferation of T lymphocytes and inhibit the activity of cytotoxic T lymphocytes. That may be one of the underlying mechanisms of immune escape of tumor and immune tolerance of T lymphocytes.