Table 1.
Distribution of Human and Mouse Fcγ receptors, their variants on effector cell subsets and antibody binding selectivity
| FcγR | Motif | Variantsa | Distributionb | Subclass selectivityc | Effector functiond |
|---|---|---|---|---|---|
| Human FcγR | |||||
| FcγRI (CD64) | ITAM | NA | Monocyte, Macrophages, Neutrophils (inducible), Dendritic cells (inducible) | IgG1, IgG3, IgG4, mIgG2a,**mIgG2b | ADCP |
| FcγRIIA (CD32A) | - | H131, R131 | Monocytes, Macrophages, Neutrophils, Dendritic cells | IgG1, IgG2, IgG3, IgG4 | ADCP |
| FcγRIIB (CD32B) | ITIM | I232, T232 | B cells, Dendritic cells, Monocytes, Macrophages | IgG1, IgG3, IgG4 | Immune inhibition |
| FcγRIIC (CD32C) | - | Q57, * | NK cells (inducible), Neutrophils, Monocytes | IgG1, IgG2, IgG3, IgG4 | ADCC |
| FcγRIIIA (CD16) | ITAM | V158, F158 | NK cells, Macrophages, Neutrophils, NK cells, Dendritic cells | IgG1, IgG2, IgG3, IgG4 | ADCC |
| FcγRIIIB (CD16B) | GPI anchor | **NA1(R36N65D82V106) NA2(S36S65N82I106), SH |
Neutrophils | IgG1, IgG3 | Immune inhibition |
| FcRn | NA | Endothelial cells, epithelial cells | IgG1, IgG2, IgG3, IgG4 | Antibody recycling & transport | |
| Mouse FcγR | |||||
| FcγRI (CD64) | ITAM | NA | DC, Monocytes, Macrophages | mIgG2a, mIgG2b | ADCP |
| FcγRIIB (CD32B) | ITIM | NA | B cells, DC, Neutrophils, Monocytes, Macrophages | mIgG1,mIgG2a, mIgG2b, IgG1 | Immune inhibition |
| FcγRIII | ITAM | NA | NK, DC, Monocytes, Macrophages, Neutrophils | mIgG1,mIgG2a, mIgG2b | ADCC |
| FcγRIV | ITAM | NA | DC, Monocytes, Macrophages, Neutrophils | mIgG2a, mIgG2b, IgG1 | ADCP |
| FcRn | NA | NA | Endothelial cells, epithelial cells | mIgG1,mIgG2a, mIgG2b, IgG3 | Antibody recycling & transport |
Notes: a. Data for the existence of FcγR variants is adapted from 79-82. b. FcγR distribution on different effector cells is compiled from 83-86. c. Antibody selectivity data is compiled from 85, 87, 88. d. Effector function data is compiled from 84-86. * Stop codon, *** NA1 and 2-neutrophil specific antigen 1 and 2, **m= denotes for mouse antibodies. NA, not available; ITAM, immunotyrosine based activation motif; ITIM, immunotyrosine based inhibitory motif; DC, dendritic cells; NK, natural Killer; ADCC, antibody dependent cell cytotoxicity; ADCP, antibody Dependent cell phagocytosis