Importance of polymorphonuclear leucocytes in protection of mice against Escherichia coli.

Bacterial growth and lethality of Escherichia coli infection of mice were enhanced by X-irradiation but not by treatment with carrageenan. Since carrageenan depletes macrophages but not polymorphonuclear leucocytes, it is concluded that protection against E. coli, at least in the early phases, depends mainly on polymorphonuclear leucocytes.