Table 1.
Characteristics of different types of stem cells
| ESC | iPSC | SSC |
|---|---|---|
| Derived from inner cell mass of blastocyst | Derived from somatic cells | Isolated from postnatal adult tissue |
| Allogenic material | Autologous or allogenic material | Autologous or allogenic material |
| Pluripotent | Pluripotent | Multipotent |
| Can differentiate in cell types of all three germ lineages | Can differentiate in cell types of all three germ lineages | Can differentiate in limited cell types depending on the tissue of origin |
| Ability to form chimeras | Ability to form chimeras (maybe more difficult than for ESCs) | Cannot form chimeras |
| Self-renewal | Self-renewal | Limited self-renewal |
| Require many steps to drive differentiation into the desired cell type | Require many steps to manufacture (e.g. genetic modification) and to drive differentiation into the desired cell type | Difficult to maintain in cell culture for long periods |
| High degree of proliferation once isolated | High degree of proliferation | Ease of access, yield and purification varies, depending on the source tissue |
| Indefinite growth | Indefinite growth | Limited lifespan (population doublings) |
| Production of endless number of cells | Production of endless number of cells | Production of limited number of cells |
| Chromosome length is maintained across serial passage | Chromosomes tend to shorten with ageing | Chromosomes tend to shorten with ageing |
| Significant teratoma risk | Significant teratoma risk | No teratoma risk |
| Serious ethical issues | No ethical issues | No ethical issues |
| Immuno-priviliged. Low level of MHC I and II (also in ESC-derived cells) | Not immuno-priviliged when derived from adult cells. Normal level of MHC I and II molecules. | MSC have low immunogenicity and are immunomodulatory. Not known for other somatic SC. |
| Cell lines will be allogenic | Less chance immune rejection in case of HLA-matching | In case of autologous use, less chance of immune rejection, but immunogenicity in allogenic and non-homologous applications remains unpredictable |
| Donor history may be unknown for 'old' cell lines (i.e. initially not intended for clinical application) | Targeted disease may still be present in stem cell in case of autologous use | Targeted disease may still be present in stem cell in case of autologous use |