Oyer, Jeremiah L., Igarashi, Robert Y., Kulikowski, Alexander R., Colosimo, Dominic A., Solh, Melhem M., Zakari, Ahmed, Khaled, Yasser A., Altomare, Deborah A., Copik, Alicja J.
funding text
The authors thank the Florida Hospital Gala Endowed Program for Oncology Research and the Florida Department of Health NIR Bankhead-Coley Biomedical Research Program (3BN02) for financial support.
abstract
Natural killer (NK) cell immunotherapy as a cancer treatment shows promise, but expanding NK cells consistently from a small fraction (similar to 5%) of peripheral blood mononuclear cells (PBMCs) to therapeutic amounts remains challenging. Most current ex vivo expansion methods use co-culture with feeder cells (FC), but their use poses challenges for wide clinical application. We developed a particle-based NK cell expansion technology that uses plasma membrane particles (PM-particles) derived from K562-mbIL15-41BBL FCs. These PM-particles induce selective expansion of NK cells from unsorted PBMCs, with NI( cells increasing 250-fold (median, 35; 10 donors; range, 94 to 1492) after 14 days of culture and up to 1265-fold (n = 14; range, 280 to 4426) typically after 17 days. The rate and efficiency of NK cell expansions with PM-particles and live FCs are comparable and far better than stimulation with soluble 41BBL, IL-15, and IL-2. Furthermore, NK cells expand selectively with PM-particles to 86% (median, 35; range, 71% to 99%) of total cells after 14 days. The extent of NK cell expansion and cell content was PM-particle concentration dependent. These NK cells were highly cytotoxic against several leukemic cell lines and also against patient acute myelogenous leukemia blasts. Phenotype analysis of these PM-particle-expanded NK cells was consistent with an activated cytotoxic phenotype. This novel NK cell expansion methodology has promising clinical therapeutic implications. (C) 2015 American Society for Blood and Marrow Transplantation.