Mobilities of cord blood granulocytes were studied using the agarose plate method and Boyden's chamber method. In the agarose plate, granulocytes of cord blood were shown to have moderately decreased responses in chemotaxis and chemokinesis induced by Escherichia coli-derived chemotactic factor and/or zymosan-activated serum, whereas they were shown to have a normal capacity of random mobility. Although their distance and index of chemotaxis or chemokinesis in the agarose plate were significantly less than those of adult granulocytes, response rate in both types of mobility were evidently higher compared with those in patients with chemotactic defect. Furthermore, there is a difference between chemotactic responses of cord blood granulocytes to E. coli-derived chemotactic factor and to zymosan-activated serum in the agarose plate method. Using the latter, a more distinguishable difference between chemotactic responses of cord blood granulocytes and adult granulocytes was shown.Speculation
The impaired chemotactic function of the cord blood granulocyte may be due to developmental immaturity in chemokinetic and/or chemotactic response, and the degree of impairment may be moderate.