Cord blood polymorphonuclear leukocyte chemotaxis. Differential response to formyl peptide and endotoxin-activated serum.

The chemotactic responses of cord blood polymorphonuclear leukocytes (PMN) to two different chemotactic factors, N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys (F-peptide) and the endotoxin-activated serum (EAS), were compared with that obtained with adult PMN. Cord blood PMN chemotactic response to F-peptide was normal, while the response to EAS was decreased (57%). The number of receptor sites for F-peptide on the membranes of cord blood PMN was also found to be normal (120,000 receptors/cell). The differential chemotactic response of cord blood PMN may suggest a poorly developed receptor system for the EAS, in which complement-derived peptides are the major chemoattractants.