Chemotactic responses of various differentiational stages of neutrophils from human cord and adult blood.

Chemotactic response and responsiveness, that is, the ability to respond to various concentrations of the chemoattractant zymosan-activated serum was measured for cord and adult blood neutrophils. Chemotactic response of neutrophils from adult blood was two to seven times greater than that of neutrophils from cord blood. In addition, neutrophils from cord blood showed poor response to concentrations of 25% chemoattractant or less, compared to those from adults, which responded to concentrations of 10%. Further, it was found that approximately 30% of neutrophils in cord blood were the band form compared to only 9% in adult. Based upon this, a simple method was devised to assay mean migrating distance of various differentiational stages of neutrophils incorporating both distance and magnitude of their responses. The results of these assays showed that all differentiational stages of cord blood neutrophils have a mean migrating distance less than those of adults. In addition, the band form from both cord and adult blood had a mean migrating distance less than the polymorphonuclear form. Adherence studies revealed that all differentiational stages of neutrophils adhered in a similar manner, and no difference was detected between cells from cord and adult blood. Assays to test the ability of cord blood to produce chemotactic activity when activated revealed 50% less activity than that obtained from adult serum which further decreased with dilution of attractant. These data suggest that both the cellular and humoral systems involved in chemotactic responses are less in cord blood compared to adult blood.