[Biological characteristics of PHA-induced CIK cells and its killing activity to K562 cells]

The purpose of study was to investigate the in vitro proliferation ability of PHA-induced CIK cells and traditionally prepared CIK cells, the effector cell level and its influence on killing activity to K562 cells, and to analyze the difference between them. The peripheral blood mononuclear cells(PBMNC) of healthy persons were isolated and divided into A and B group. The CIK cells in A group were obtained by using traditional culture method, the CIK cells in B group were prepared by PHA induction. During the cultivation, the cell survival rate and cell absolute value in the cell culture system were counted every 3 days. On day 15 of culture, the cell immunophenotype of 2 groups were detected by flow cytometry, and the ratios of CD3(+)CD56(+), CD3(+)CD8(+) and CD3(+)CD4(+) cells in total cell amount of culture system were accounted. Meantime, the killing activity to K562 cells in different effector-target ratios was detected by using CCK-8 kit between the 2 groups. The results showed that the method of preparing CIK by PHA induction promoted the cell proliferation more than that of the traditional method (P < 0.05), moreover, both the survival rate of cells in 2 groups was more than 90%. The CD3(+)CD8(+), CD3(+)CD56(+) cell ratio in 2 groups obviously increased. As compared with traditional method, the CD3(+)CD8(+) cell level in B group was enhanced (P < 0.05); but there were no statistical differences in increase of CD3(+)CD56(+) cell level and decrease of CD3(+)CD4(+) cell level between 2 groups. while the effector-target ratio is 5:1, 10:1, 20:1 and 40:1, the killing activity of PHA-induced CIK cells to K562 cells was more stronger than traditionally-prepared CIK cells (P < 0.05), moreover, along with increase of effector-target ratio, the difference of killing activity to K562 cells in 2 groups significantly increased. It is concluded that compared with traditional method for preparing CIK cells, the new way by PHA induction can increase the proliferation of CIK cells obviously, enhance the ratio of CD3(+)CD8(+) cells and strengthen the killing activity to the K562 cells. This new way provides a new source of CIK cells and reliable evidence for cyto-immune therapy of leukemia and other tumors.