Table 1.

Intestinal immunologic defects in germ-free mice

Intestinal organ development	Site	Phenotype in Germfree mice
Small Intestine	Peyers Patches	fewer, less cellular
	Lamina propria	thinner, less cellular
	Germinal centers	fewer plasma cells
	Isolated lymphoid follicles	smaller, less cellular
Mesenteric Lymph nodes	Germinal centers	smaller, less cellular
		fewer plasma cells

Cellular Defects	Cell Type	Phenotype in Germfree mice
Intestinal epithelial lymphocytes	CD8+ T cells	fewer, reduced cytotoxicity
Lamina propria lymphocytes	CD4+ T cells	proportional decrease in number
		decreased Th17 cells (Small intestine)
		increased Th17 cells (Colon)
Mesenteric lymph nodes	CD4+CD25+ T cells	reduced expression of Foxp3
		reduced suppressive capacity

Molecular immune deficiencies	Molecule	Phenotype in Germfree mice
Paneth Cells	Angiogenin-4	reduced expression
	RegIIIγ	reduced expression
B cells	Secretory IgA	reduced production
Intestine	ATP	reduced
Intestinal epithelial cells	MHC class II	reduced expression
	TLR 9	reduced expression
	IL-25	elevated