Table 1.

Characteristics of T helper subsets.

	Th1 cells	Th2 cells
Inducing stimuli	IL-12, IFN-γ, IL-18, IL-27, PRR signalling	IL-4
Transcription factors	STAT4, STAT1, T-bet, NFκB	STAT6, GATA3
Cytokines produced	IFN-γ, IL-2, TNF, lymphotoxin α	IL-4, IL-5, IL-13 (IL-10 in mice)
Chemokine receptor expression	CXCR3, CCR5, CCR1	CCR3, CCR4, CCR8
Antibody isotypes	Human: IgG1, IgG3, IgG2	Human: IgG4, IgE
	Mouse: IgG2a, IgG3, IgG2b	Mouse: IgG1, IgE
Effector response	Cell-mediated immunity, macrophage activation, antibody-mediated cellular cytotoxicity	Activation of eosinophils, allergy