NATURAL KILLER CELLS EXPANSION FOR ADOPTIVE IMMUNOTHERAPY: COMPARISON OF TWO ISOLATION METHODS, THREE CYTOKINES, IL-2, IL-15, or IL-18 AND IMPACT ON NK CYTOTOXICITY

Natural killer cells are progressively considered as medical tools for cancer immunotherapy. The development of applicable methods to generate large numbers of functional NK cells is a crucial step to maximize the potential of this approach. In this article, NK cells were isolated from PBMCs using 2 different methods. One method with MagniSort Human NK cell Enrichment kit, and the second method isolation with antibodies and complement (cytotoxic method). Purified NK cells were activated in vitro by IL-2 and IL-15 for 14 days and we used IL-18 on day 14 for another 48 hours to increase the cytotoxicity. Finally, the HL-60 (Human promyelocytic leukemia cells) cell line was used as a target to assess NK cytotoxic activity. The purity of NK cells was 86% and 92% by cytotoxic and MACS methods, respectively. NK cells expanded 60-100 fold in day 14. The expanded NK cells were highly cytotoxic (90%) and they were more than 80% viable. Interestingly, the cytotoxic activity of NK cells was decreased in presence of IL-18. In this paper, we present a simple approach that enables the isolation of NK cells without any beads and magnets using mouse complement with anti-CD3 and anti-CD19 and compared it with the routine isolation method, using magnetic cell sorting. This simplified and efficient method for NK cells isolation and activation could be used in future clinical trials.