POLYMORPHONUCLEAR LEUKOCYTE HETEROGENEITY IN NEONATES AND ADULTS

  • 1 July 1986
    • journal article
    • research article
    • Vol. 68  (1) , 200-204
Abstract
We have used a mouse monoclonal antibody (31D8) to determine whether differences in neutrophil (PMN) subpopulations might help explain decreased PMN chemotaxis in neonates compared with that of adults. 31D8 has been shown to bind heterogeneously to adult PMNs. Approximately 80% of the PMNs that strongly bind 31D8 (31D8 "bright") are the same cells that depolarize and migrate chemotactically when stimulated with the chemoattractant N-formyl-methionylleucylphenylalanine, while the 20% that weakly bind 31D8 fail to similarly respond. All neonatal PMNs bound 31D8 heterogeneously. There was a smaller population of 31D8 "bright" cells in neonates at birth (76% .+-. 6%, n=45) compared with that of neonates at three of 15 days of age (82% .+-. 5%, n=10, P < 0.002) and both were smaller than that of adults (88% .+-. 4%, n=45, P < 0.001 and P < 0.001). Neonatal cord PMNs, which traversed a micropore filter in a modified Boyden chemotaxis chamber in the presence of a chemoattractant had an increased percentage of 31D8 "bright" cells (89% .+-. 7%) than did PMNs which remained above the filter (82% .+-. 7%, n=10, P=0.034). PMN chemotaxis was less in neonates at birth (32.7 .+-. 4.5 .mu.m) than at three to six days of age (36.8 .+-. 11.3 .mu.m) and both were decreased compared with that of adults (69.1 .+-. 12.4 .mu.m, P < 0.001 and P < 0.001). These findings indicate that decreased PMN chemotaxis in neonates may be due in part to a smaller PMN subpopulation of highly motile cells.