Human ovarian carcinoma cells generate CD4+CD25+ regulatory T cells from peripheral CD4+CD25− T cells through secreting TGF-β

Increased CD4+CD25+ regulatory T cells predicted poor prognosis in ovarian carcinoma patients. This study aimed to define whether soluble substances secreted by ovarian carcinoma could up-regulate the proportion of CD4+CD25+ regulatory T cells. Similar to TGF-β, the low MWF (<50 kDa) of supernatant derived from SKOV3 could convert part of freshly isolated CD4+CD25− T cells into CD25+ population with similar characters as natural CD4+CD25+ regulatory T cells. To deplete TGF-β in the low MWF by neutralizing anti-TGF-β would eliminate this transformation phenomenon. These results indicate that TGF-β secreted by ovarian carcinoma cells owns vital function in the process of converting peripheral CD4+CD25− T cells into CD4+CD25+ regulatory T cells, which may provide one immunotherapeutic target for ovarian cancer.