Table 1.
A summary and comparison of proposed immunomodulatory mechanisms of MSCs in studies reviewed herein
| Cell/mechanism | Immune effect | Proposed MOA | Model | Reference |
|---|---|---|---|---|
| Adaptive immunity | ||||
| CD4+/CD8+ suppression | ↓T-cell proliferation, ↑survival | IFN-γ priming/IDO metabolism | In vitro/vivo | 22,23 |
| CD4+/CD8+ death | ↑T-cell apoptosis? | IFN-γ priming/IDO metabolism | In vitro | 47 |
| T cell–Treg polarization | ↓Inflammation? | IFN-γ/cytokine/paracrine | In vitro | 48 |
| B-cell suppression | ↓B proliferation | IFN-γ/cytokine/paracrine | In vitro | 43,44 |
| Innate immunity | ||||
| Polarize M2 macrophages | ↓Inflammation | Monocyte/IFN-γ MSC priming | In vitro | 19,21,53 |
| Macrophage recruiting | ↑Tissue repair | Chemotaxis to damaged tissue | In vitro/vivo | 19,24,54 |
| Monocyte recruiting | ↑Tissue repair | Chemotaxis to damaged tissue | In vitro/vivo | 19,24,54 |
| Apoptotic MSCs | Immunosuppression | Phagocytic-induced suppression | In vitro/vivo | 55-57 |
IDO, indoleamine 2,3-dioxygenase; MOA, mechanism of action; Treg, regulatory T cell; ↑, increased; ↓, decreased.