Abstract
Neutrophils rely on active reorganization of the cytoskeleton during movement, and functional deficiencies in the cytoskeletal elements may result in impaired neutrophil-mediated host defense. We have compared and quantitated actin polymerization in neonatal (≤48 h old) and adult bovine peripheral-blood polymorphonuclear leukocytes (PMN) using fluorescence flow cytometry. Baseline filamentous actin (F-actin) content of neonatal and adult PMN at time zero differed slightly but were not statistically different (p > 0.05). F-actin content of recombinant human C5a (10-7 M)-stimulated neonatal PMN increased rapidly within 10 s of stimulation to 59.0% over baseline, then declined. F-actin in adult recombinant human C5a-stimulated PMN continued to increase for 30 s and was elevated 87.3% over baseline before subsequently declining. When stimulated with zymosan-activated bovine serum (10%), neonatal (120.7% increase) and adult PMN (115.1% increase) had similar profiles with no significant differences, and both groups reached peak F-actin levels at 30 s after stimulation. Neonatal PMN stimulated with platelet-activating factor (10-6 M) attained peak F-actin values at 10 s (72.0% increase over baseline), but actin rapidly depolymerized by 30 s poststimulation (reduced to 29.0% increase). Adult PMN stimulated by platelet-activating factor also attained peak values by 10 s (97.6% increase over baseline), but in contrast to neonatal PMN the F-actin remained elevated at 30 s in the adult PMN (still increased 79.5%; p <0.0.5 compared to neonatal Factin). Our results suggest that stimulus-specific variation may exist between responses of neonatal and adult bovine PMN to different agonists, but actin polymerization is rapid and PMN were stimulus-responsive in both age groups.
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Bochsler, P., Neilsen, N. & Slauson, D. Comparative Actin Polymerization in Neonatal and Adult Bovine Neutrophils In Vitro. Pediatr Res 32, 509–513 (1992). https://doi.org/10.1203/00006450-199211000-00002
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DOI: https://doi.org/10.1203/00006450-199211000-00002