Study On Biological Characteristics Of Induced And Amplified Natural Killer Cells With IL-2and IL-15from The Cord Blood

Objective To investigate the amplification of CD3-CD56+NK cellsderived from umbilical cord blood and their immunophenotype and cytotoxicitychange.Methods Mononuclear cells were isolated from umbilical cord blood and cultured inserum-free medium supplied with IL-2or/and IL-15for14days. The subset ofCD3-CD56+NK cells and their expression of CD16,CD62L,NKG2A,NKG2D,NCR44,NCR46,granzyme B and perforin were analyzed by flow cytometry. The cytotoxicityof NK cells against K562was detected by WST-1method.Results NK cells of IL-2, IL-15and IL-2/IL-15group were amplified by10.78±2.51,10.42±3.72, and10.54±6.24times respectively after14days later, therewas no significant difference between these three groups. The expression of CD16decreased obviously after NK cells amplified; there was significantly differencebetween IL-2and IL-15group.The expression of CD62L didn’t change aftercytokines stimulated. IL-2has reduced the expression of NKG2A and NCR46, whileIL-15has the opposite effect. IL-2or IL-15has effect of upregulating the expressionof NKG2D, perforin and NCR44, but there was significantly difference between thosetwo cytokines. IL-15increased the expression of granzyme B on NK cells. Thecytotoxicity of NK cells derived from cytokines stimulated and amplified significantlyincreased, but there was no significant difference between IL-2and IL-15.Conclusion IL-2or IL-15could effectively amplify umbilical cord blood NK cells onserum-free conditions, although the immunophenotype associated with NK cells function showed different characteristic between them. However, cytotoxicity allincreased significantly after amplified and there was no significant difference betweenthese two kinds of cytokines as well synergistic effect was not obviously. Thecytotoxicity of NK cells is the combined effect of all active molecules.