Table 1.
Expression, function and main ligands of complement receptors.
| Receptor | Alternative name | Main ligands | Main leukocyte expression | Main functions |
|---|---|---|---|---|
| C3aR | / | C3a | Neutrophils Basophils Eosinophils Monocytes Mast cells Activated T-lymphocytes Tonsil-derived B-lymphocytes |
Chemotaxis of mast cells, eosinophils and monocytes/macrophages (Daffern et al., 1995; Hartmann et al., 1997; Zwirner et al., 1998) Induction of ROS production in neutrophils (Elsner et al., 1994) No (or inhibition of) chemotaxis of neutrophils (Daffern et al., 1995; Wu et al., 2013) Retention of hematopoietic stem cells in the bone marrow (Reca et al., 2003; Ratajczak et al., 2004) Leukocyte recruitment to the brain (Wu et al., 2016; Crider et al., 2018) Regeneration of skeletal muscle and hepatic tissue (Strey et al., 2003; Markiewski et al., 2004; Zhang et al., 2017) |
| C5aR | C5aR1 | C5a | Neutrophils Monocytes/macrophages Dendritic cells T-lymphocytes B-lymphocytes Mast cells |
Chemotaxis of neutrophils, monocytes, dendritic cells, T- and B-lymphocytes (Morgan et al., 1993; Sozzani et al., 1995; Nataf et al., 1999; Ottonello et al., 1999) Degranulation of neutrophils (Morgan et al., 1993) Induction of ROS production in neutrophils (Sacks et al., 1978) Cytokine production in monocytes (Morgan et al., 1993) Mast cell histamine release (Johnson et al., 1975; Füreder et al., 1995) Liver regeneration (Mastellos et al., 2001; Daveau et al., 2004; Marshall et al., 2014) |
| C5L2 | C5aR2 | C5a | Immature dendritic cells Granulocytes (Myeloid immune cells) T cell subsets |
Immune suppressing and immune activating functions due to regulation of C5aR activation and signaling (Li et al., 2019) |
| CR1 | CD35 C3b/C4b receptor |
C1q C3b C4b iC3b MBL |
Erythrocytes Monocytes/macrophages Granulocytes B-lymphocytes CD4+ T-lymphocytes FDCs Glomerular podocytes |
Immune regulatory role (Iida and Nussenzweig, 1981; Masaki et al., 1992) Immune-complex clearance (Cornacoff et al., 1983) Phagocytosis (Fällman et al., 1993) |
| CRIg | VSIG4/B7 family- related protein Z39Ig |
C3b C3c iC3b |
Tissue-resident macrophages MDDCs | Complement-mediated phagocytosis (Wiesmann et al., 2006) Immune regulatory role (Vogt et al., 2006; Munawara et al., 2019) |
| CR2 | CD21 | iC3b C3dg C3d gp350/220 (EBV) CD23 Interferon-alpha |
B-lymphocytes FDCs T-lymphocytes Epithelial cells |
Lowering B-lymphocyte activation threshold (Carter and Fearon, 1992) Retention of C3-opsonized antigens (Reynes et al., 1985) Promotion of B-lymphocyte class switching and IgE production (Aubry et al., 1992) EBV cell entry (Tanner et al., 1987) |
| CR3 | Mac-1 CD11b/CD18 Integrin αMβ2 |
ICAM-1 ICAM-2 Fibrinogen iC3b Collagen Factor X NIF |
Neutrophils Monocytes/macrophages Dendritic cells NK cells Activated lymphocytes |
Leukocyte extravasation (Dustin and Springer, 1988; Meerschaert and Furie, 1995; Ding et al., 1999; Phillipson et al., 2006) Phagocytosis (Beller et al., 1982) |
| CR4 | p150,95 CD11c/CD18 Integrin αXβ2 |
ICAM-1 ICAM-2 Fibrinogen iC3b Collagen Factor X NIF |
Neutrophils Monocytes/macrophages Dendritic cells NK cells Activated lymphocytes |
Adhesion to fibrinogen (Sándor et al., 2016) Phagocytosis (Keizer et al., 1987) |
EBV, Epstein-Barr virus; FDCs, follicular dendritic cells; ICAM, intercellular adhesion molecule; Mac-1, macrophage-1 antigen; MBL, mannose-binding lectin; MDDCs, monocyte-derived dendritic cells; NIF, neutrophil inhibitory factor; NK, natural killer; ROS, reactive oxygen species; VSIG4, V-set and Ig domain 4.