|
| IgM
| IgG
| IgA |
| Types of antibody (mode of reaction)
| mainly complete
| mainly incomplete
| both types |
| Source of antigenic stimulus
| usually non-red cell stimulated ("naturally occurring")
| usually red cell stimulated (immune)
| usually red cell stimulated (immune) |
| Complement fixation
| yes (good)
| yes (some)
| no |
| Can cause HDN (can cross the placenta)
| no
| yes
| no |
| Inactivated by 2-mercaptoethanol (2-ME) or dithiothreitol (DTT)
| yes
| no
| variable |
| Inactivated by heating to 56° for 3 hours
| yes
| no
| no |
| Approximate molecular weight in daltons [1 dalton = 1.66 x 10-24 g]
| 1,000,000
| 150,000
| 150,000 |
| Sedimentation coefficients (in Svedberg units)
| 19S
| 7S
| 90% 7S
10%-17S |
| Present in external secretions
| no
| no
| yes |
| Concentration in serum (g/L)
| 0.4 - 2.3
| 6.0 - 15.0
| 0.4 - 3.3 |
| Half life (days)
| 5
| 25
| 6 |
| Subclasses (H-chain)
| (mu)
| 4 (gamma)
| 2 (alpha) |
