Analysis of selected variables in the under-agarose assay for chemotactic responses of canine neutrophils.

Chemotaxis under agarose was evaluated to establish an assay system and to characterize chemotactic responses of canine neutrophils. A method for the measurement of canine neutrophil chemotaxis was established, with optimal responses obtained with agarose containing 10% pooled canine serum, a concentration of 5 x 10(5) cells/well, zymosan-activated serum (ZAS), or autologous serum or plasma as the chemoattractants, and a 120-minute incubation period. Canine neutrophils responded well to ZAS, heat-inactivated ZAS, autologous serum and plasma, and heat-inactivated pooled serum. Chemotactic activity was proportional to the concentration of serum used as the chemoattractant. Mean (+/- SD) random migration, chemotaxis, chemotactic index, and chemotactic differential of neutrophils from 9 healthy Greyhounds were 1.09 (+/- 0.23), 1.95 (+/- 0.38), 1.82 (+/- 0.31), and 0.86 (+/- 0.32) mm, respectively.