title: Comparative actin polymerization in neonatal and adult bovine neutrophils in vitro.
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 (< or = 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 F-actin).(ABSTRACT TRUNCATED AT 250 WORDS)
authors: Department of Pathobiology, College of Veterinary Medicine, University of Tennessee, Knoxville 37901.
authors: P N
authors: PN
authors: Bochsler
authors: N R
authors: NR
authors: Neilsen
authors: D O
authors: DO
authors: Slauson
mesh_terms: D000199:Actins / Q000097:blood*; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D002417:Cattle; D007107:Immune System / Q000254:growth & development; D066298:In Vitro Techniques; D007700:Kinetics; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism*
chemical_list: D000199:Actins