Tu76 - A Robust, Xeno- and Feeder-Free Culture System for Expansion of Human Peripheral Blood NK Cells

Tuesday, June 21, 2022

6:15 PM – 7:45 PM PT

Presenting Author(s)

NT

Nooshin Tabatabaei-Zavareh, MD, PhD

Associate Director
STEMCELL Technologies
Vancouver, British Columbia, Canada

Co-Author(s)

TL

Tim A. Le Fevre, BSc

Scientist
STEMCELL Technologies
Vancouver, British Columbia, Canada
EA

Elaine Ang, BSc

Senior Research Technologist
STEMCELL Technologies
Vancouver, British Columbia, Canada
AW

Albertus W. Wognum, PhD

Senior Principal Scientist
STEMCELL Technologies
Vancouver, British Columbia, Canada
AE

Allen C. Eaves, MD, PhD

President and CEO
STEMCELL Technologies
Vancouver, British Columbia, Canada
SL

Sharon A. Louis, PhD

Senior Vice President, Research & Development
STEMCELL Technologies
Vancouver, British Columbia, Canada
AK

Andy I. Kokaji, PhD

Senior Director, Immunology
STEMCELL Technologies
Vancouver, British Columbia, Canada

Natural killer (NK) cells are lymphocytes that play an important role in innate immunity against tumors and viral infections by secreting proinflammatory cytokines and exhibiting cytotoxicity. NK cells hold promise for the development of cancer immunotherapies against solid tumors. We have developed a culture system for expansion of peripheral blood NK cells without feeder cells, serum, or xeno components. Freshly isolated NK cells were cultured for two weeks in ImmunoCultTM NK Cell Expansion Medium and on ImmunoCultTM NK Cell Expansion Coating Material. CD56+CD3- NK cells expanded 88 ± 17-fold (n = 34, mean ± SEM), with an average frequency of 87 ± 1%. To assess functionality, the expanded NK cells were stimulated with phorbol 12‐myristate 13‐acetate (PMA) and ionomycin, or co-cultured with K562 cells. On average, 75 ± 4.0% of NK cells stimulated by PMA/ionomycin and 48 ± 3.6% of NK cells stimulated by K562 cells expressed intracellular interferon-γ (n = 13). Stimulated NK cells also expressed surface CD107a, a marker of degranulation (88 ± 4.8% [PMA/ionomycin] and 74 ± 5.8% [K562 co-culture]). Directed NK cell killing of target K562 cells was measured in co-cultures. K562 cells were treated with a substrate that is cleaved by activated caspase-3/7 resulting in the release of a fluorescent dye. At an effector:target ratio of 1:1, an average of 48 ± 2.4% of K562 cells were killed (n = 9). Therefore, this culture system enables xeno- and feeder-free generation of large numbers of functional NK cells.