An enzyme-assessed microplate-assay for neutrophil adherence. I. IgA-induced adherence of human PMNs.

The binding of PMNs to extracellular matrix and cells is crucial to PMN host defense. Adherence mechanisms and the many families of molecules involved are major areas of study. We present here details of an enzyme-assessed microtiter plate assay for neutrophil adherence. This assay uses low numbers of cells (50,000/well) and permits analysis of several hundred wells in a short period of time, by using an ELISA reader. With this assay we observed 5- to 10-fold increases in the number of adherent human PMNs in response to nanogram amounts of LPS or as little as 5.0 micrograms/ml of aggregated IgA. Although fluoride blocked the LPS-induced adherence response, IgA-induced cell binding was largely unaffected.