Expanded NK cells used for adoptive cell therapy maintain diverse clonality and contain long-lived memory-like NK cell populations

David S J Allan; Chuanfeng Wu; Ryland D Mortlock; Mala Chakraborty; Katayoun Rezvani; Jan K Davidson-Moncada; Cynthia E Dunbar; Richard W Childs

doi:10.1016/j.omto.2022.12.006

Expanded NK cells used for adoptive cell therapy maintain diverse clonality and contain long-lived memory-like NK cell populations

Mol Ther Oncolytics. 2022 Dec 27:28:74-87. doi: 10.1016/j.omto.2022.12.006. eCollection 2023 Mar 16.

Authors

David S J Allan¹, Chuanfeng Wu², Ryland D Mortlock², Mala Chakraborty¹, Katayoun Rezvani³, Jan K Davidson-Moncada¹, Cynthia E Dunbar², Richard W Childs¹

Affiliations

¹ Laboratory of Transplantation Immunotherapy, Cellular and Molecular Therapeutics Branch, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
² Translational Stem Cell Biology Branch, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
³ Department of Stem Cell Transplantation and Cellular Therapy, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.

Abstract

Multiple clinical trials exploring the potential of adoptive natural killer (NK) cell therapy for cancer have employed ex vivo expansion using feeder cells to obtain large numbers of NK cells. We have previously utilized the rhesus macaque model to clonally track the NK cell progeny of barcode-transduced CD34⁺ stem and progenitor cells after transplant. In this study, NK cells from barcoded rhesus macaques were used to study the changes in NK cell clonal patterns that occurred during ex vivo expansion using culture protocols similar to those employed in clinical preparation of human NK cells including irradiated lymphoblastoid cell line (LCL) feeder cells or K562 cells expressing 4-1BBL and membrane-bound interleukin-21 (IL-21). NK expansion cultures resulted in the proliferation of clonally diverse NK cells, which, at day 14 harvest, contained greater than 50% of the starting barcode repertoire. Diversity as measured by Shannon index was maintained after culture. With both LCL and K562 feeders, proliferation of long-lived putative memory-like NK cell clones was observed, with these clones continuing to constitute a mean of 31% of the total repertoire of expanded cells. These experiments provide insight into the clonal makeup of expanded NK cell clinical products.

Keywords: NK cell clones; NK cell expansion; NK cell repertoire; adaptive NK cells; barcode tracking; in vitro expansion; irradiated feeder cell; memory NK cells; natural killer cell; rhesus macaque.