Table 1.
Advantages and disadvantages of new technologies for CAR-NK production
| Advantages | Disadvantages | |
|---|---|---|
| NK cell type | ||
| NK-92 | • Easy to expand and to engineer; • Homogenous product; • Low in vivo persistence. |
• Safety risk; • Requires irradiation; • No CD16 expression. |
| Peripheral Blood | • Easy to obtain; • Does not require irradiation; • Highly cytotoxic. |
• Difficult expansion; • Low transduction; efficiency; • Sensitive to freeze/thaw cycles; • Non homogenous. |
| Cord blood | • Ease of collection; • Fewer T cells; • Presence of unique NK progenitors; • High proliferation capacity. |
• Difficult expansion; • Non homogenous product; • Immature cells. |
| iPSC | • Yields more cells; • Easy to engineer; • Homogenous product. |
• Longer production period; • Immature phenotype; • Low in vivo persistence; • Potentially immunogenic; • Potentially tumorigenic. |
| NK expansion methods | ||
| Cytokines combination | • Promotes differentiation of memory-like natural killer cells. | • Requires high initial number of cells; • High cost; • Increases the chance of Treg activation. |
| Synthetic beads/antibodies | • Easy handling; • Easy to scale up. |
• Low to moderate expansion; • Expensive. |
| Feeder cells | • Efficient activation and high expansion. | • Complex co-culture system. |
| Membrane particles | • High expansion rates. | • Laborious process of fabrication and characterization; • Risk of residual stimulatory cell material in the final product |
| Gene delivery | ||
| Retroviruses | • Permanent modification of cells. | • Requires actively dividing cells; • Random integration profile (Risk of insertional mutagenesis); • Potential of replication competent retrovirus (RCR); • High manufacturing cost of GMP-grade vectors. |
| Lentiviruses | • Transduction of non-dividing cells; • Permanent modification of cells. |
• Random integration profile (risk of insertional mutagenesis); • Potential of replication competent retrovirus (RCL); • High manufacturing cost of GMP-grade vectors. |
| Transposons | • Cost-effective; • Easier to produce on a large scale; • Large insert capacity; • Stable transgene expression. |
• High cell death rates; • Low integration rate; • Risk of insertional mutagenesis. |
| CRISPR/Cas 9 technology | • Site-specific integration of gene of interest; • Permanent expression of CAR |
• Possible off-target effects; • Low delivery efficiency; • Licensing restrictions |
| mRNA | • Low risk of insertional mutagenesis; • High efficiency of genetic material delivery. |
• Inherently labile; • Short period of expression. |
| Episomes | • Stable expression; • Cost-effective; • Low risk of insertional mutagenesis; • Safety profile compared to viral methods. |
• A good delivery method is still needed. |