Expression of perforin in cord blood NK cells after IL-2/IL-15 stimulation and its relation with cytotoxicity / 中国实验血液学杂志

ABSTRACT

This study was aimed to investigate the expression level of perforin in cord blood NK cells and the relation of perforin expression after IL-2, IL-15 stimulation to cytotoxicity of NK cells. NK cells were isolated from cord blood MNC by depleting CD3(+) cells and then enriching CD56(+) cells using immunomagnetic separation (CD3 and CD56 cell isolation kit, autoMACS, miltenyi). The purity was analysed by flow cytometry. According to the different combination of cytokines, there were two groups group A (IL-2) and group B (IL-2 + IL-15). The cytotoxicity and perforin expression rate of fresh and different cultured CB-NK cells against K562/Jurkat cell lines were estimated by LDH release test (cytotoxic 96 non-radioactive cytotoxicity assay). The results showed that the purity of NK cells after separation was more than 90%. The cytotoxicity towards both tumor lines in group B was higher than that in group A (p < 0.05), and cytotoxicity in group A was higher than that of fresh NK cells (p < 0.05). Perforin expression rate of group A (84.55%) was higher than that of fresh NK cells (67.21%) (p < 0.05), and there was no significant difference between group A and B (84.55% versus 87.22%) Cytotoxic activity of CB-NK cells was positively correlated with perforin expression rate (r = 0.886, p < 0.05). It is concluded that IL-2 can enhance cytotoxicity of CB/BM-NK cells by increasing the perforin expression.