Table 2.
Measurement of QC specifications
| Quality attribute | Measurement methods for CGT therapies | ||
|---|---|---|---|
| Cell-based (i.e., MSCs) [19] | Gene-based (i.e., AAV, LV) [30, 31] | Cell-based gene (i.e., CAR-T cell) [57, 58] | |
| Identity |
Morphology (microscopy) Immunophenotyping (FACS) Differentiation potential (respective staining method) |
Viral protein (ELISA) Vector genome copies (PCR) Specific viral proteins (western blot) or sequences (sequencing) |
% of T cells % of CAR-expressing T cells (FACS) |
| Viability | Cell counting (i.e., acridine orange, propidium iodide, or trypan blue) | NA | Cell counting (i.e., acridine orange, propidium iodide, or trypan blue) |
| Purity | Residual contaminants, such as FBS (ELISA) | Residual contaminants, such as host cell proteins or DNA (ELISA, qPCR) |
% of other immune cells (FACS) Residual contaminants, such as beads and feeder cells (FACS) |
| Potency | Secretion of paracrine factors (ELISA) |
Titer (qPCR) In vitro functional assay |
In vitro assay (i.e., cytotoxic T lymphocyte assay) |
| Endotoxin | Bacterial endotoxin test (i.e., LAL) | LAL | LAL |
| Adventitious agents | Adventitious assay (in vitro and in vivo) | Adventitious assay (in vitro and in vivo) | Adventitious assay (in vitro and in vivo) |
| Mycoplasma | Test for mycoplasma (NAT) | Test for mycoplasma | Test for mycoplasma (NAT) |
| Sterility | Sterility testing (bacteria and fungi) | Sterility testing (bacteria and fungi) | Sterility testing (bacteria and fungi) |
| Replication competence | NA | RCV assay | RCV assay |