Table 1.
Co-receptors of γδ T-cells – extracellular ligands and intracellular signaling pathways.
| Receptor | Ligands | Intracellular signaling initiators/adaptors | Downstream signaling pathway | Target molecules | Reference |
|---|---|---|---|---|---|
| CD28 | B7.1 (CD80) B7.2 (CD86) | PI3K ITK Grb2 | PI3K/AKT Grb2/MEK/ERK | IL-2, NF-κB, AP-1, Bcl-xL, NFAT | (42–45) |
| CD27 | CD70 | TRAF2 TRAF5 Siva | IKK/NF-κB JNK | NF-kB, Ca2+, cyclinD2, Bcl2a1, Bcl-xL | (46–49) |
| CD30 | CD30L | TRAF2 TRAF5 | TRAF/IKK/IkB Ca2+ | NF-κB, IL-4, IFNγ, IL-8, CC chemokines | (46, 50, 51) |
| 4-1BB (CD137) | CD137L | TRAF2 | NF-κB, IFNγ | (52 –54) | |
| IL-2R IL-15R | IL-2 IL-15 | Jak1 Jak3 | PI3K/AKT Jak/STAT4/STAT5 MEK/ERK STAT1 | IFNγ, TNF-α, T-bet, eomesodermin | (55–58) |
| IL-7R | IL-7 | Jak1 Jak3 | STAT3 | IL-17, SOCS3 | (59) |
| IL-21R | IL-21 | Jak1 Jak3 | STAT3 | CXCL13, CXCR5 | (60) |
| NKG2D | MIC(A–B) | DAP10 | PI3K/AKT | NF-κB, RelB, Bcl-xL, Bcl-2 | (32, 46, 61–63) |
| ULBP (1–6) | Grb2/VAV1/SOS1 | ||||
| H60 | PKCθ/Ca2+ | ||||
| MULT1 | |||||
| RAE1 | |||||
| NKp30 | B7-H6 BAT3 | CD3ζ | cAMP/PKA | CC chemokines: CCL3, CCL4, CCL5 | (64–67) |
| NKp44 | NKp44L | DAP12 | Zap70/Syk | (64, 68–70) | |
| DNAM-1 (CD226) | Nectin-like-5 Nectin-2 | PKC LFA-1 Fyn | SLP-76/VAV1/ERK | (71, 72) | |
| PD-1 | PD-L1 (B7-H1) PD-L2 (B7-DC) | SHP-1 SHP-2 | CK2/PTEN/PI3K/AKT MEK/ERK | GSK-3, Bcl-xL Smad3, Cdc25A, IFNγ, IL-2 | (73–76) |
| BTLA | HVEM | SHP-1 | Zap70/ERK | IL-17, TNF, IL-2 | (77–79) |
| SHP-2 |