title: Irreversible neutrophil aggregation. A mechanism of decreased newborn neutrophil chemotactic response.
abstract: To investigate the neutrophil-neutrophil interactions of the newborn for possible clues to the etiology of decreased newborn neutrophil (PMN) chemotaxis, the authors compared adult and newborn C5a-induced PMN aggregation and chemotaxis at various PMN concentrations. Using Craddock's technique of C5a-induced aggregation, the authors found that the newborn lacks the normal biphasic aggregation-deaggregation seen in the adult, suggesting irreversible aggregation similar to that seen when adult PMNs are pretreated with cytochalasin-B. Chemotaxis of adult and newborn PMNs was studied with a modified Gallin radiolabel technique. A linear correlation between PMN concentration and corrected chemotactic response was found with both adult (r2 = 0.93) and newborn (r2 = 0.90) PMNs in the range 0.1 X 10(6) to 20 X 10(6) PMNs/ml. Random migration was not augmented by increased PMN concentration. The augmentation of newborn PMN chemotaxis was less than that of the adult (adult slope = 2426; newborn slope = 983). Irreversible newborn PMN aggregation may be the underlying event producing decreased PMN chemotaxis and interfering with the normal chemotactic augmentation caused by increased PMN concentration.
mesh_terms: D002449:Cell Aggregation; D002465:Cell Movement; D002634:Chemotaxis, Leukocyte; D003182:Complement C5; D003571:Cytochalasin B / Q000494:pharmacology; D005312:Fetal Blood / Q000276:immunology*; D006801:Humans; D007231:Infant, Newborn; D009504:Neutrophils / Q000276:immunology*; D015054:Zymosan / Q000494:pharmacology
chemical_list: D003182:Complement C5; D003571:Cytochalasin B; D015054:Zymosan