OK-432によりヒト末梢血単核球に誘導されるキラー細胞に関する研究

特にNK活性について

抄録

Natural killer (NK) cell activity of OK-432-stimulated peripheral blood mononuclear cells (PBMC) was examined. Low concentrations of exogenously added recombinant interleukin 2 (rIL-2) were able to augment OK-432-induced NK cell activity. This kind of augmenting effect depended on the dose of rIL-2 and manifested itself only in PBMC stimulated with OK-432 (OK-MC) followed by rIL-2; augmentation did not happen when drugs were applied in the reverse order.
The existence of CD16+ /CD25+ (IL-2 receptor positive; IL-2R+) and CD57+ /CD25+ double positive cells which possess NK cell surface markers in OK-MC markedly increased in a long-term culture (12 days). A strong positive correlation was observed between the IL-2-dependent augmentation of NK activity and the quantitative changes in cell populations that possessed NK cell phenotypes. Furthermore, this augmenting effect was detectable within 4 h after addition of rIL-2 at single cell level, suggesting that the effect did not require NK cell's DNA synthesis.
Thus, the use of OK-432 activated NK cells in combination with IL-2 in clinical trials is expected to afford high efficiency in cancer immunotherapy.