Table 1.

Summary of IgG subclass effector functions.

				Binding to FcγR alleles
	ADCC (NK)	Complement activation	Antigen recognized	FcγRI CD64	FcγRII CD32a-H	FcγRII CD32A-R	FcγRII CD32b	FcγRIII CD16a-V	FcγRIII CD16a-F	FcγRIII CD16b-NA1	FcγRIII CD16b-NA2
IgG1	+++	+++	T-dep protein	+++	++	+++	+	+++	++	+++	+++
IgG2	+	+b	Carbohydrate and T-dep protein	−	++	+	−	+	−	−	−
IgG3	+++	+++	T-dep protein	+++	++	+++	++	+++	+++	+++	+++
IgG4	a	−	T-dep protein	+++	+	+	±	++	−	−	−

^aADCC elicited by IgG4 depends on the glycosylation pattern of the Fc region.

^bComplement activation by IgG2 depends on the titer of antibody and the density of antigen.