A Method for Assessing thein vitroChemotactic Response of Neutrophils Utilizing51FR-Labeled Hliman Leukocytes

A method is described for the quantitation of the in vitro chemo-tactic response of human neutrophilic polymorphonuclear leukocytes utilizing modified Boyden chambers, a layer of two micropore filters, and 51Cr-labeled leukocytes. Either human C5a or human kallikrein in the stimulus compartment resulted in migration of labeled neutrophils through the top micropore filter and into the second filter with maximum chemotaxis after 5-6 hrs of incubation at 37°C, measured by counting the 51Cr rzdioactivity in the second filter. The value of the 6 hr chemotactic response was directly proportional to the concentration of chemotactic factor and was reproducible within ±20% of the mean with duplicate OK triplicate chambers at each concentration of chemotactic factor. The development of an objective method for assessing chemotaxis is critical to studies of the relationship of rate of leukocyte migration to dose of chemotactic factors, and ultimately for the evaluation of intrinsic leukocyte responsiveness in various clinical circumstances.