Table 2.
Ex vivo cultivation of natural killer (NK) cells with accessory cells.
| Protocol features | Starting material/culture system | NK cell expansion rate | NK cell purity | NK cell phenotype | NK cell function | Setting | Reference |
|---|---|---|---|---|---|---|---|
| IL-2 | PBMC, CD3 depleted in bags and flasks | N/A (overnight) | 33% NK 0.1% T cells | N/A | N/A | Clinical | (60) |
| N/A (14–16 h) | 26.7% | Enhanced cytotoxicity In vitro | (61, 62) | ||||
| N/A (overnight) | 40% NK 0.9% T cells | Enhanced cytotoxicity In vitro | (43) | ||||
| IL-15 | PBMC, CD56 enriched | 23 (20 days) | 98% NK | Expression of NKp30, NKp44, NKp46, NKG2D, and 2B4 | Cytotoxic in vitro | Clinical | (63) |
| IL-15 + IL-21 | PBMC, CD3 depleted | 3.7 CD56+/CD122+ (2–3 weeks) | >90% CD56+/CD122+ <0.3% CD3+/CD56− <3% CD3+/CD56+ |
67% CD56+CD16+ | Cytotoxic against K562 and patient bone marrow blasts | Clinical | (64) |
| OKT-3 + IL-2 | PBMC in plates | 193 (21 days) | ~55% NK ~22% T cells |
N/A | Substantial cytotoxicity against K562 | In vitro | (65) |
| PBMC in flasks | 1,625 (20 days) | ~65% NK ~22% T cells |
Upregulated: 2B4, CD8, CD16, CD27, CD226, NKG2C, NKG2D, NKp30, NKp44, NKp46, LIR-1, KIR2DL3, and CXCR3 Downregulated: CCR7 |
Increased cytotoxicity against tumor cell lines and primary MM cells In vitro | In vitro | (25) | |
| PBMC | 1,036 (total cells) (19 days) | ~30% NK ~40% T cells |
Upregulated: NKG2A, LILR-B1, NKG2D, NKp30, NKp44, and NKp46 | In vitro cytotoxicity increases during culture | Clinical | (66) | |
| PBMC in a bioreactor, flasks, and plates | 77—bioreactor 530—bags 770—flasks (20 days) |
38%—bioreactor 31%—bags 44%—flasks |
Bioreactor compared to flasks: higher expression of CD11b, NKG2D, and NKp44 | Bioreactor compared to flasks: higher cytotoxicity | In vitro | (67) | |
| OKT-3 + IL-2 + Alemtuzumab | PBMC in plates, flasks, and bags | 646 (14 days) 1,537 (18 days) |
60% NK 37% T cells <0.1% B cells |
Upregulated: 2B4, NKG2D, NKp30, NKp44, KIR2DL1, LIR-1, and CD16 Downregulated: CCR7 |
Increased cytotoxicity In vitro and in vivo |
Clinical | (68) |
| OKT-3 + IL-2 + IL-15 | PBMC or CD56+ + CD56− (1:1) in flasks and bioreactor (Cellbag) | PBMC: 112 1:1 Mix: 89 (21 days) |
With PBMC: 34% With “1:1 Mix”: 92% |
Upregulated: NKp30, NKp44, DNAM-1, NKG2D, and CD11a | Increased activity against neuroblastoma cell lines in vitro and in vivo | Preclinical model | (69) |
| aCD16 mAb + OK432 + IL-2 | PBMC in flasks and bags | 637–5,712 (day 21) | 79% NK 8.4% T cells (day 21) |
Upregulated: NKG2D, NKp44, and CD69 Downregulated: CD16 (transient) |
Increased cytotoxicity against tumor cell lines and primary cancer cells in vitro ADCC activity |
In vitro | (70) |