Characterization of Nonmotile Neutrophil Subpopulations in Neonates and Adults

Abstract

ABSTRACT. Previous studies have demonstrated that polymorphonuclear leukocytes (PMN) are not a homogeneous population of cells but differ significantly in their structure and function. P M N move a t varying rates, and a fraction estimated from 20 to 70% do not move a t all in response to chemotactic stimuli. To characterize this P M N subpopulation better, we studied P M N motility in neonates and adults using a polycarbonate micropore filter chemotactic assay and the 31D8 MAb. Most P M N strongly bind 31D8 MAb (31D8 "bright"), but a minority (31D8 "dull") weakly bind the antibody and in this respect are similar to immature P M N precursors. The 31D8 "dull" P M N have impaired function compared with 31D8 "bright" PMN. In the present study, a P M N subpopulation that failed to migrate using the micropore filter assay accounted for 58 f 7% of adult P M N and was similar to the migrating subpopulation in regard to viability and phagocytic function. The nonmotile subpopulation had a higher percentage of bands (5 f 3% versus I f 2%, p < 0.01) and decreased binding of 31D8 MAb compared with the motile subpopulation. Neonates had a larger nonmigrating P M N subpopulation and 31D8 "dull" P M N subpopulation than those of adults (76 + 3% versus 58 f 7%, p = 0.04 and 26 f 11% versus 8 5 2%, p < 0.01, respectively). These data indicate that although P M N appear morphologically a s a homogeneous population of cells, there exists a viable, nonmotile P M N subpopulation that may be less mature than the motile P M N subpopulation. They also indicate that impaired neonatal P M N motility may be attributable in part to an increased size of the nonmotile P M N subpopulation. of PMN structure and function have confirmed that PMN are a heterogeneous group of cells (3-10). It has previously been shown that PMN from adults differ in their ability to move and that a percentage d o not move at all in response to chemotactic stimuli (1, 3-6). Estimates of the size of the poorly motile PMN subpopulation have varied, and the characteristics of this PMN subpopulation have not been well described. T o further characterize PMN chemotactic subpopulations, we studied PMN motility in healthy adults and in newborn infants using a polycarbonatc filter chemotactic assay and two cell surface MAb (31D8 and Mo-I) binding assays. The 31D8 MAb binds PMN heterogeneously and is associated with PMN motility (9-10). Mo-l binds to a cell surface glycoprotein which helps mediate PMN adherence (I 1 -13). A poorly motile PMN subpopulation was identified in adults and neonates and was found to be larger in neonates. Poorly motile PMN were noted to be viable cells that have similar phagocytic function but decreased binding of 3 1 D8 and Mo-l MAb compared with motile PMN. MATERIALS A N D M E T H O D SStudy popllkulion. Blood was obtained from the fetal side of placentas (neonatal cord blood) within 5 min of birth. Placentas were obtained from healthy women who had delivered vaginally or by repeat cesarian section who had local anesthesia, no complications of pr...

Neutrophil Production and Function in Newborn Infants

“…That is to say, neonates have a larger population of inactive phagocytic cells which can be detected through functional studies but which are not related to morphological immaturity ). This was supported by studies which showed neonates to have a larger population of non-motile cells in chemotaxis assays (Krause et al, 1986b(Krause et al, , 1989) and a higher percentage of cells that do not produce an oxidative respiratory burst when stimulated (Gessler et al, 1996;Drossou et al, 1997). However, this does not explain why the inactive cells are different.…”

Comparative Differences and Combined Effects of Interleukin-8, Leukotriene B4, and Platelet-Activating Factor on Neutrophil Chemotaxis of the Newborn

“…Furthermore, the increase in chemotaxis observed with the combined submaxima1 dose was still 36% of the level observed for adult neutrophils under the same conditions. Explanations for limited chemotaxis in the newborn have included a large subpopulation of immobile cells (21) with decreased actin polymerization (22,23), decreased membrane fluidity or deformability ( l l ) , and decreased interferon-y-induced calcium entry (24). Although we found an appreciable difference in chemotaxis between the two age groups, our study suggests that motile neutrophil subpopulations may be greater than previously considered for the newborn if more than one chemoattractant is used at submaximal doses or a single but maximal chemoattractant dose is used.…”

Heterogeneity in phagocytic and oxidative burst activities of neutrophils and neonatal calves

“…Cells that bind to these monoclonals with high affinity have greater chemotactic activity, and are present in lesser numbers in neonates than in adults (Krause et al 1989). …”

“…Host susceptibility to infection may be influenced by a marked reduction in numbers, or a substantial decrease or the absence of phagocytic and bactericidal activities of neutrophils (Ganz et al 1986;Lehrer et al 1988;Sawyer et al 1989). Previous studies have indicated that neutrophils from human and bovine newborns exhibit varying degrees of functional impairment of phagocytosis and oxidative burst activities compared to neutrophils from adults (Krause et al 1989;Clifford et al 1989;Holden et al 1989;Smith et al 1990). Further study of the variation in phagocytic and oxidative burst activities of neutrophils is important for better understanding of early calfhood morbidity and mortality attributable to infectious disease.…”