Scientist Bioprocessing Technology Institute, Singapore
Abstract: As a cell type with minimal risk of causing graft-versus-host disease, natural killer (NK) cells are of interest for clinical applications in allogeneic adoptive cell therapy, particularly with chimeric antigen receptor-based therapies. In contrast to T cells, they are also able to mediate tumour cell killing via a variety of pathways, including direct ligand activation and antibody-dependent cellular cytotoxicity. The expansion of large NK cell quantities from healthy donors is still a technical challenge, with limited cell numbers available via the culture of primary cells. To address this, functional protocols to produce NK cells from induced pluripotent stem cells (iPSCs) at laboratory scale have been developed. However, these established protocols have process development challenges, including the use of unscalable plate-bound DLL4 to provide Notch signalling. Here, we outline the development of a scalable protocol for the differentiation of iPSCs to NK cells. Using DLL4-conjugated microbeads, we have developed a differentiation protocol that is amenable to scale-up studies, in particular dynamic cell culture systems that are compatible with eventual bioreactor-scale processes – the addition of DLL4 microbeads under wave-like mixing conditions provides the differentiating cells with sufficient Notch signalling required for the HSPC-to-NK cells differentiation phase. Using this protocol, we can generate approximately 10^3 NK cells from each iPSC over the course of 3.5 weeks, producing functional NK cells that can be further expanded. The process outlined here has implications for the scalable manufacture of NK cells, which will be required to produce sufficient quantities of this class of cell therapeutics for clinical applications.
Funding Source: ICP2300163; A*STAR‐SCG Joint Laboratory for Manufacturing of Allogeneic Cellular Immunotherapies
