Immune activation of erythroleukemia cells induced by interleukin 12.
To investigate the antitumor activity of IL-12, the induction of differentiation of IL-12 was observed using erythroleukemia cells (FBL-3) as model. After incubation with 200 U/mL IL-12 for 48 h, DNA synthesis of FBL-3 cells in S phase decreased significantly; the expression of CD14 which is the specific marker of monocyte increased, the rate of NBT(+) cells was apparently higher than that of the untreated FBL-3 cells. After treating FBL-3 cells with IL-12 for 72 h, the expression of 33D1 and NLDC145 which are the specific markers of dendritic cells increased markedly, the surface molecules such as MHC-11, B7-1, B7-2, and VCAM-1 were up-regulated; morphological observation showed two kinds of cells: some cells had a ruffled surface and plentiful lysosome; the others had many dendritic projections on the surface, and contained numerous mitochondria. Functionally, the IL-12-treated FBL-3 cells could apparently stimulate the proliferation of allogeneic and autologous T lymphocytes, and improve the specific cytotoxic activity of CTL on FBL-3 cells. These results indicated that erythroleukemia cells were induced by IL12 to differentiate into the monocytes and dendritic cells, then exhibited the antigen-presenting function. The data outline a new mechanism for IL-12 to treat leukemia.
Yong
Z
Z
Department of Immunology, Second Military Medical University, 200433, Shanghai, China.
Xuetao
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