Ex Vivo Expansion of Highly Purified Human NK Cells..

To optimize the expansion of high purity NK cells from human peripheral blood and explore the changes in biological functions of NK cells after Ex vivo expansion.

NK cells were isolated from PBMNC by using miniMACS (Magnetic cell-selection) and NK Cell Isolation Kit II(Miltenyi Biotec, Germany), then they were cultured in SCEM (Stemline Hematopoietic Stem Cell Expansion Medium, Sigma) supplemented with 10% human AB serum and different combinations of interleukin (IL)-2 and/or IL-12, IL-15 for 15 days. Cultures were fed with fresh media and cytokines every 3 days, and were evaluated for cell expansion, phenotype, perforin and granzyme B mRNA expressions, and IFN-γ secretion at the end of the culture period.

In group IL2+IL15 and IL2+IL15+IL12, cells were expanded 50.46±4.31 and 52.35±6.72 fold, respectively, much more higher than others(P<0.01), but no significant difference between them (P>0.05). And the purity of CD3⁻CD56⁺NK cells was over 94% in all groups except the control. The expressions of perforin and granzyme B mRNA of expanded NK cells cultured with cytokines was significantly higher than the starting population(P<0.01), although IL2+IL15+IL12 group was slightly higher than that of IL2+IL15 group, without significant difference (P>0.05). There was great increase in IFN-γ levels in the supernatants of NK cells culture in the presence of cytokines; IL2+IL15+IL12 group and IL2+IL12 group was significantly higher than others(P<0.01).

High purity NK cells could be efficiently expanded in culture with IL2+IL15, and its biological functions were enhanced in this condition.

No relevant conflicts of interest to declare.