Table 1. Effect of gut microbiota on autoimmune diseases.

Disease	Animal model	Manipulation method of microbiota (signal)	Effects in GF animal	Reference
IBD	IL-2−/−	GF	less severity	64
	TCRαβ−/−	GF	no disease	66
	IL-10−/−	GF	no disease	65
	Helicobacter hepaticus-induced colitis in Rag−/−	introducing B. fragilis	less severity	73
	DSS-induced colitis	introducing Clostridium	less severity	43
RA	IL-1Rn−/−	GF	no disease	84
	IL-1Rn−/−	introducing Lactobacillus bifidus to ex-GF IL-1Rn−/− mice	restores disease	84
	TLR2−/−IL-1Rn−/−	n/a	increased severity	84
	TLR4−/−-IL-1Rn−/−	n/a	less severity	84
	K/BxN	GF	less severity	16
	K/BxN	introducing SFB to ex-GF K/BxN	restores disease	16
T1D	NOD	GF	severe disease to no difference*	88–90,92,93
	NOD female	SFB natural colonization	protection by SFB	91
	NOD male	SFB natural colonization	no difference	91
	MyD88−/−NOD	GF	severe disease	90
	MyD88−/−NOD	n/a	no disease	90
Multiple sclerosis	EAE	GF	less severity	95
	EAE	introducing SFB to GF EAE	restores disease	95
	EAE	introducing B. fragilis	less severity	96
	Established EAE	introducing 3 strains of Lactobacillus	therapeutic effect	99
APECED	AIRE−/−	GF	no difference	101
	MyD88−/−Aire−/−	n/a	no difference	101
Systemic lupus erythematosus	MRL/1pr	GF	no difference	102
Autoimmune gastritis	AID−/−	GF	no difference	103

^*The discrepancy of difference in disease severity between GF and SPF NOD mice is likely due to the variability of microbiota composition among different SPF facilities.