Figure 10: Evaluation of natural killer cell activity. Effector cell (isolated spleen cell) and target cells (YAC-I) were cultured at an effector : target ratio of 10 : 1 in RPMI 1640 media. The culturing media were prepared by mixing with different amount of suspended layer from the RPMI 1640 media mixed with 1% of QELBY powder and left for 24 hours. NK cell activity was assessed using CCK-8 assay to measure cell cytotoxicity against YAC-I cells. The results are expressed as mean ± SD . Bars with different superscript are significantly different at .