Table II.
Main molecules secreted and expressed by basophils.
| Mediators | Role | Main membrane receptors | Ligands | Main membrane receptors | Ligands |
|---|---|---|---|---|---|
| Histamine PAF (highly expressed) Granzyme B β-hexosaminidase Chondroitin sulphate Elastase Lysophospholipase Tryptase B LTC4 |
These compounds are released during basophil activation and degranulation (exocytosis through degranulation). They are immune mediators (histamine and PAF), vaso-active amines and endothelial interacting substances. | Receptors for chemokines | Complement receptors | ||
| CCR1 | MIP-1α | CD11b (Mac-1) | CD54, iC3b | ||
| CCR2 | MCP-1 | CD11c | Fibrinogen | ||
| CD193 (CCR3) | Eotaxin | C3bi, C3d, C3g | |||
| CD195 (CCR5) | CD21 | EBV, C3d, C3g | |||
| CXCR1 | IL-8 | CD35 | C3b, C4b | ||
| CXCR2 | GRO-α | CD46 | C3b, C4b | ||
| CD170 (CXCR4) | SDF-1 | CD55 | C4b/2a, C3b/Bb | ||
| CRTH2 | PGD2 | CD59 | C5b-8, C5b-9, CD2 | ||
| CD88 | C5a | ||||
|
Main cytokines IL-4 (highly expressed) IL-13 IL-3 IL-5 IL-6 IL-25 |
Main cytokines are IL-4 (which drives to Th2 and B-cell maturation, IgE production), IL-13 which promotes allergy inflammation, IL-5, which is a chemoattractant for eosinophils, IL-6 and IL-25 as immune modulators. (for other information see text) | Receptors for cytokines | |||
| CD25 | IL-2 | Immunoglobulin receptors | |||
| CD116 | GM-CSF | ||||
| CD123/CD131 | IL-3 | LIR | |||
| CD124 | IL-4 | FcɛRI | |||
| CD125 | IL-5 | FcγRIIA, FcγRIIB | |||
| CD128 | IL-8 | ||||
| IL-18R | IL-18 | Selectins and integrins | P- and L- selectins | ||
| IL-25R | IL-25 (IL-17E) | CD15s (Lex) | MADCAM, CD34 | ||
| IL-33R | IL-33 | CD62L | P- and L- selectins | ||
|
Growth factors GM-CSF TLSP VEGF |
TLSP is the main growth factor, together with IL-4, for Th0 (naïve) maturation to Th2. GM-CSF and IL-3 are basophil growth factors and survival cytokines, VEGF (mostly produced by mast cells) contributes to endothelial tissue repair and growth during the inflammatory response | CD162 | ICAM-1, 2 and 3 | ||
| Toll-like receptors | CD11a (LFA-1) | (CD54) | |||
| TLR-2 | PDG | ICAMs | |||
| TLR-4 | LPS | CD18 | Laminin, collagen | ||
| TLR-9, TLR-10 | CD29 | Hyaluronic acid | |||
| CD44 | Laminin, collagen | ||||
| Other receptors | VLA-1 | Fibronectin, VCAM-1 | |||
| HLA class I | VLA-4 | ||||
| HLA class II (low expr.) | |||||
| CD40 | CD40L | ||||
|
Chemokines MIP-5 Eotaxin, RANTES IL-8, MPC-1 Leptin CCL22 (MDC) MIP-1α, MIP-1β CCL3 CCL5 |
Most of the chemokines attract neutrophils and monocytes towards the site of inflammation | CD40L | CD40 | ||
| Basophilin, 212H6 | Unknown Substance P, NGF | ||||
| Somatostatin | Unknown Substance P, NGF | ||||
| Substance P, NGF-R |