Protection against experimental necrotizing enterocolitis by maternal milk. I. Role of milk leukocytes.

A rat model of necrotizing enterocolitis of the neonate in which maternal milk had been protective was studied to determine what components of the milk afforded protection and by what mechanism. Frozen and thrawed rat milk was not protective, but formula supplemented with rat milk cells was. It was concluded that the cells provided protection. The cells, which are principally mononuclear phagocytes, can phagocytize and kill the Klebsiella pneumoniae strain used in the animal model. Animals with necrotizing enterolitis had peritonitis and bacteremia caused by this bacillus.