Leukocyte migration agarose test for the assessment of human neutrophil chemotaxis. II. Variables in the attraction assay.

Optimal conditions for the attraction assay of human neutrophil leukocytes were studied, using the leukocyte migration agarose test (LMAT). Larger migration areas were obtained toward the attractant wells when they were filled with zymosan-activiated serum (ZAS) in advance than when both the attractant and the cells were added simultaneously. Chemotactic indices (CI; the ratio between the migration rate toward attractant and that toward the control substance) decreased when the number of applied neutrophil leukocytes increased, whereas migration differentials (MD; the difference between the migration rate toward attractant and that toward the control substance) were not markedly affected. Both the spontaneous and the directed migration rates, and CI and MD of neutrophil leukocytes obtained from the same donor on different days varied markedly. When tested repeatedly, however, the neutrophil leukocytes of different donors migrated on the average rather equally toward inactivated serum, as they also did toward ZAS, and the variation of the means of CI and MD was insignificant.