Table 1
From the following article
Isotype selection in antibody engineering
Jochen G Salfeld
Nature Biotechnology 25, 1369 - 1372 (2007)
doi:10.1038/nbt1207-1369
Table 1. Key features of the four IgG isotypes
| IgG1 | IgG2 | IgG3 | IgG4 | |
|---|---|---|---|---|
aHomodimers of IgG2 are tetravalent for a given antigen, but heterodimers are also expected. | ||||
bFrom ref. 2. | ||||
cFrom ref. 22. | ||||
dFrom ref. 23. | ||||
eFrom ref. 2. | ||||
fDiscussed in ref. 12. | ||||
| Functional form in vivo | Monomeric bivalent | Dimeric tetravalenta | Monomeric bivalent | Half-Ig monovalent |
| Biological role in host response | Protein antigens | Carbohydrate antigens | Protein antigens | Response to chronic stimulation, anti-inflammatory |
| Percentage of all IgG in humansb | 60% | 25% | 10% | 5% |
| Half-life (range in days)c | 36.3  9.2 (17.6–56.2) | 37.1 13.9 (22.9–62.5) | 28.6 10.4 (13.0–50.2) | 15.6 4.5 (7.1–24.7) |
| Allotypesd | 4 | 1 | 13 | 0 |
| FcRne | + | + | + | + |
| Hinge length (number of amino acids) | 15 | 12 | 62 | 12 |
| Potential (actual) inter-heavy chain disulfide bonds in hinge region | 2 (2) | 4 (4?f) | 11 (11) | 2 (2) |
| Effector functions | ||||
| C1e | ++ | – | +++ | – |
| FcgRIe | +++ | – | +++ | ++ |
| FcgRIIe | + | | + | ? |
| FcgRIIIa/be | + | – | + | |