Effect of high doses of radiation on human neutrophil chemotaxis, phagocytosis and morphology.

Human neutrophils were exposed to varying amounts of ionizing radiation up to 1,000,000 rad and evaluated as to their ability to respond to chemotactic stimuli and phagocytize and kill bacteria. Striking morphologic and functional resistance to radiation was apparent. At doses up to 5,000 rad there was little or no impairment of chemotaxis. As the dosage increased to 50,000 rad, chemotaxis decreased to approximately 50% of nonirradiated control values. At very high doses of radiation (250,000 to 1,000,000 rad) neutrophils failed to respond significantly to chemotactic stimuli. Effects of radiation as measured by phagocytosis and the degree of ultrastructural change paralleled the chemotaxis results.