Table 1. Comparison of the different properties of IgG and IgY.

	IgG	IgE	IgY
Species	Mammals	Mammals	Birds, reptiles, amphibians and lungfish
Molecular weight (kDa)	150	200	180
Isoelectric point (pI)	6.4–9.0	5.2–5.8	5.7–7.6
Concentration (mg/mL)	10–12 (serum)	10−4	8–10 (Serum) 15–25 (Egg Yolk)
Number of constant domains	4 (3 H and 1 L)	5 (4 H and 1 L)	5 (4 H and 1 L)
Hinge	Yes	No	No
Complement binding	Yes	No	No
Rheumatoid factor binding	Yes	No	No
Fc receptor binding	Yes	No	No
Mediates anaphylaxis	No	Yes	Yes
Binding to protein A/G	Yes	No	No