Alpha-Type 1 Polarized Dendritic Cells Loaded with Apoptotic Allogeneic Breast Cancer Cells Can Induce Potent Cytotoxic T Lymphocytes against Breast Cancer / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Various tumor antigens can be loaded onto dendritic cells (DCs) to induce a potent cytotoxic T lymphocyte (CTL) response in DC-based immunotherapy against breast cancer. However, in the clinical setting, obtaining a sufficient number of autologous tumor cells as a source of tumor antigens is a laborious process. We therefore investigated the feasibility of immunotherapy using breast-cancer-specific CTLs generated in vitro by use of alpha-type 1 polarized DCs (alpha DC1s) loaded with ultraviolet B-irradiated cells of the breast cancer cell line MCF-7. MATERIALS AND METHODS: alphaDC1s were induced by loading allogeneic tumor antigen generated from the MCF-7 UVB-irradiated breast cancer cell line. Antigen-pulsed alphaDC1s were evaluated by morphological and functional assays, and the breast-cancer-specific CTL response was analyzed by cytotoxic assay. RESULTS: The alphaDC1s significantly increased the expression of several molecules related to DC maturation without differences according to whether the alphaDC1s were loaded with tumor antigens. The alphaDC1s showed a high production of interleukin-12 both during maturation and after subsequent stimulation with CD40L, which was not significantly affected by loading with tumor antigens. Breast-cancer-specific CTLs against autologous breast cancer cells were successfully induced by alphaDC1s loaded with apoptotic MCF-7 cells. CONCLUSION: Autologous DCs loaded with an allogeneic breast cancer cell line can generate potent breast-cancer-specific CTL responses. This may be a practical method for cellular immunotherapy in patients with breast cancer.

Selective Expansion of Natural Killer Cells from Peripheral Blood Mononuclear Cells by K562 Cell Line and IL-2

BACKGROUND: Several attempts have been made to expand human NK cells from peripheral blood mononuclear cells (PBMCs). This study examined the selective expansion of NK cells using interleukin 2 (IL-2) plus the K562 cell line, the expression of the NK cell receptors, and the cytotoxic activity. METHODS: The PBMCs from seven healthy volunteers were cultured in a medium containing the IL-2 plus the K562 cell line for 14 days. The expression of the activating and inhibitory receptors on the resting NK cells and the 72 hr-expanded NK cells were analyzed. A flow cytometric cytotoxic assay was used to determined the killing activity of the non-expanded NK cells and the 7 day-expanded NK cells against the K562 target cells. RESULTS: The NK cells from PBMCs expanded 4.5-fold after 7 days, and contained 56.5% CD3-CD56+ cells. The IL-2 or IL-2 plus K562 increased the expression levels of CD158b (MFI, mean florescence intensity), CD158e1/e2 (MFI), and NKp44 (MFI), while it decreased the expression levels of NKp30 (%), CD16 (MFI), and 2B4 (MFI). The non-expanded NK cells lysed 9.0% and 27.6% of the K562 target cells in the 1 : 1 and 5 : 1 effector and target ratio, respectively, and the 7-day expanded NK cells lysed 36.9% and 57.2% of the K562 target cells, respectively. CONCLUSION: The selective expansion of CD3-CD56+ NK cells occurred only during 7 days of culture. IL-2 or IL-2 plus the K562 cells altered the expression of various activating and inhibitory receptors of NK cells, and the cytotoxicity of the expanded NK cells was higher than in the non-expanded cells.