Viral and Nonviral Engineering of Natural Killer Cells as Emerging Adoptive Cancer Immunotherapies

Table 1

Differences between CAR-NK and CAR-T cells.

	CAR-NK cells	CAR-T cells
Sources	Cord blood, peripheral blood, iPSC, cell lines	Cord blood, peripheral blood, iPSC
Expansion	Flasks or bag-based expansion systems with cytokines (IL-2, IL-12, IL-15, IL-18, IL-21); or feeder cell lines (engineered K562 cells)	Flasks or bag-based expansion systems with cytokines (IL-2 or IL-7)
Use	Autologous; allogeneic possible	Autologous; allogeneic with MHC match
Engineering methods	Viral transduction, electroporation/nucleofection, nanoparticles, trogocytosis	Viral transduction, electroporation/nucleofection, nanoparticles, trogocytosis
Transfection efficiencies	Low even with viral vectors	Higher than for NK cells
Adoptive transfer considerations	Limited persistence	GvHD
		Cytokine storm
		Suicide genes needed