Oxidative metabolism of cord blood neutrophils: relationship to content and degranulation of cytoplasmic granules.

Generation of oxygen metabolites is an important component of the neutrophil's armamentarium against microbes. Production of superoxide anion (O2-) and generation of hydroxyl radical (OH) were measured in neutrophils from cord blood of 12 vaginally delivered, term newborn infants and 12 adults after stimulation with phorbol myristate acetate (PMA) and opsonized zymosan. With either stimulus, generation of OH was relatively less than production of O2- for all infants studied. This discrepancy might be related to abnormal release or diminished cell content of a cofactor necessary for production of OH from O2-. Since both lactoferrin (LF) found in specific granules and myeloperoxidase (MPO) found in azurophilic granules have been shown to enhance OH generation, we compared degranulation of both granule types in response to PMA and opsonized zymosan and total neutrophil content of MPO, LF, and lysozyme in cord blood and adult neutrophils. Degranulation, even after pretreatment with cytochalasin B, was the same for newborn and adult neutrophils. Content of MPO was identical (adult, 204 +/- 24 A units, mean +/- SEM, n = 9; newborn, 201 +/- 21, n = 9) but lysozyme was mildly diminished (adults, 111 +/- 10 A units; newborn, 89 +/- 6, n = 9, p less than 0.05), and lactoferrin was moderately decreased (adult, 89.0 +/- 7.3 micrograms/mg cell protein, n = 11; newborn, 43.2 +/- 7.0, n = 11, p less than 0.005). Generation of OH in response to PMA and LF content were measured in seven cord blood-adult control pairs.(ABSTRACT TRUNCATED AT 250 WORDS)