The primary objectives of this project are to completely investigate the biochemical and functional properties of neutrophils obtained from human infants, to identify any abnormal properties and to define the mechanisms responsible for any abnormalities. The hypothesis being pursued tests the ideas that the concentration of reactive forms of oxygen is excessive in neonatal neutrophils, and that neutrophil dysfunction is a consequence of autooxidation. A variety of studies are being performed to compare the metabolic and functional characteristics of neutrophils obtained from newborn infants with cells obtained from their mothers and controls. In addition, enzymes responsible for the detoxification of oxygen are being measured in neutrophils obtained from these subjects. Finally, evidence is being sought to document oxidative/peroxidative damage to these cells. It is hoped that information gained from these studies will help to define the physiology of oxidative metabolism in neonatal neutrophils and may provide the basis for clinical trials with investigational therapy designed to improve the ability of infants to resist or to combat infections.