The outcome indicated that Bcl xL was involved in the anti apoptotic effect of IL 15. 3 As a way to further investigate the various ramifications of IL 2 and IL 15 on NK cell proliferation, we analyzed the expression of high affinity IL 2R and IL 15R on cord blood NK cells. The expression of CD25 was significantly upregulated on NK cells, over 506 in CD56 NK cells after 14 daysculture with IL 15. The percentage of CD25 NK cells under IL 2 culture was about fraction Dub inhibitor of that under IL 15 culture. Recently remote cable blood NK cells expressed higher level of IL 15R. The degree of IL 15R was downregulated in IL 2 culture and only a small percentage of NK cells expressed IL 15R after 2 week culture. Although the expression of IL15R was also decreased in the IL 15 tradition condition, IL 15 could better maintain the expression of IL 15R on NK cells compared with IL 2. Nevertheless, there were no differences in the expression of CD122 and CD132 on NK cells cultured with IL 15 and IL 2. Both IL 2 and IL 15 are survival factors and important growth of T-cells. T cells cultured in IL 2 commonly Lymph node underwent apoptosis upon cross-linking of the Fas receptor which is very important in immune tolerance, while cells cultured with IL 15 were extremely resistant to Fas induced cell death, and IL 15 might prevent IL 2 induced AICD which features the implication of IL 15 in immune vaccination. Our results demonstrated that both IL 15 and IL 2 stimulated the proliferation and activation of cord blood NK cells, but the effects of IL 15 were consistent and reasonable. Illinois 2 fast activated NK cells and then induced AICD of CD56 cells, which can be similar to IL2 influenced T cells AICD. Interestingly, contrary to IL 2, IL 15 had a similar anti apoptotic function on NK cells as noticed in T cells. Even though both cytokines affected the CD56 NK cells in similar way, we, in the beginning time, buy Cabozantinib observed that IL 15 exerted differential results from IL 2 on CD56 NK cells. Illinois 15 experienced the development and survival of CD56 NK cells but IL 2 induced apoptosis of CD56 NK cells. Recent reports showed that CD56 NK cells can differentiate into CD56 NK cells by experience of peripheral fibroblasts and supported a linear differentiation style of human NK cells. Even though it was reported that CD56 NK cells acquired feature of CD56 NK cells upon IL 2/IL 15 activation, however in other reports and our, purified CD56 NK cells did not downregulate cell surface CD56 expression in the tradition with IL 2/IL 15. So the survival of CD56 NK cells in IL 15 culture situation did not be explained by their difference from CD56 NK cells, but that IL 15 could increase CD56 NKcell growth and inhibit CD56 NK cell apoptosis. In this study, we found that functionally much like CD4 T cells, CD56 NK cells could proliferate in response to IL 2 and IL 15, and they probably played crucial roles in immunoregulation as regulatory T cells.