Paneth cells and antibacterial host defense in neonatal small intestine.

Paneth cells are specialized epithelia in the small bowel that secrete antimicrobial proteins. Paneth cells are vital to the innate immunity of the small bowel in adult mammals, but their role during neonatal infection of the small bowel is not well established. Dithizone selectively damages Paneth cells, and when dithizone-treated newborn rats are infected enterally with Escherichia coli, the numbers of E. coli cells in their jejunal and ileal lavage fluid are significantly increased compared to controls. The data support that Paneth cells are necessary for neonatal antibacterial defense.