ABSTRACT
@#[Abstract] Objective：To investigate whether the proliferation and cytotoxicity of NK-92MI cells can be improved by IL-7 and IL-21 genes modification, and determine the effects of this genetically modified NK-92MI cells on T cells from normal human peripheral blood. Methods：IL-7 and IL-21 gene fragments were constructed into electroporation vector by genetic engineering method, and NK92MI/IL-21 and NK-92MI/IL-7&21 cells were constructed by electroporation transfection. The in vitro proliferation and cytotoxicity of NK-92MI, NK-92MI/IL-21 and NK-92MI/IL-7&21 cells were measured by cell count and flow cytometry assays. Then, normal human PBMCs were co-cultured with NK-92MI, NK-92MI/IL-21 and NK-92MI/IL-7&21 cells in vitro respectively, and the phenotype change of T cells was measured by flow cytometry. In addition, the cytotoxicity between the activated T cells and three NK-92MI cell lines (NK-92MI, NK-92MI/IL-21 and NK-92MI/IL-7&21 cells) as well as the cytotoxicity of the three NK-92MI cells on tumor cells after co-incubation with activated T cells were detected. Results: NK-92MI/IL-21 cell line (highly expressing IL-21) and NK-92MI/IL-7&21 cell line (highly expressing both IL-7 and IL-21) were successfully constructed. The toxicity of NK-92MI, NK-92MI/IL-21 and NK92MI/IL-7&21 cells on Jurkat and K562 cells showed no difference, while the proliferation of NK-92MI/IL-21 and NK-92MI/IL-7&21 cells was increased compared with NK-92MI cells. Furthermore, NK-92MI/IL-21 and NK-92MI/IL-7&21 cells promoted the activation of T cells to a certain degree, and the activated T cells showed merely no cytotoxicity on NK-92MI, NK-92MI/IL-21 and NK-92MI/IL7&21 cells; Meanwhile, the activated T cells did not affect the cytotoxicity of the three NK cells (NK-92MI, NK-92MI/IL-21, and NK92MI/IL-7&21 cells) on K562 cells under their co-existence. Conclusion: The in vitro proliferation of NK-92MI/IL-21 and NK-92MI/ IL-7&21 cells were enhanced after gene modification, which could also stimulate and promote the activation of T cells from peripheral blood. The cytotoxicity assay showed that the activated T cells had no cytotoxicity on NK-92MI, NK-92MI/IL-21, and NK-92MI/IL-7& 21 cells. Meanwhile, the presence of the activated T cells did not affect the cytotoxicity of NK-92MI cells.