Neutrophil migration under agarose: quantitation and variables.

Several variables have been evaluated for the in-vitro measurement of neutrophil migration under agarose. Commonly used anticoagulants do not alter migration. Cells may be collected in heparin, sodium citrate, or EDTA. Neither hypotonic or ammonium chloride lysis of erythrocytes affects chemotactic activity. Saponin, however, decreased both leukocytic viability and migration. Passage of neutrophils through a Hypaque-Ficoll density gradient improved migration scores, presumably by removing contaminating material and cells. Both lymphocyte and erythrocyte contamination decreased test scores. Platelets did not have a detrimental effect on neutrophil migration. Fresh serum was the most potent chemotactic agent. This was followed, in order, by zymosan-activated serum, N-formyl-L-methionyl-L-phenylalanine, casein, and Escherichia coli supernatant. A scoring method that combines features of both counting leukocytes and measuring the migration distance has been devised. The technic has a coefficient of variation of 9.2%. Scores for the normal adult population show a gaussian distribution.