Real-time monitoring of eosinophil detachment and cell death were assessed by measuring electrical impedance using the xCELLigence Real-Time Cell Analyzer (ACEA Biosciences, San Diego CA) as previously described (26 (link), 27 (link)). Briefly, media was placed in 96-well gold electrode coated plates (E-plates, ACEA Biosciences), allowed to equilibrate and a background reading was obtained. Eosinophils were then seeded at 1 × 106 cells/100 μl and allowed to settle for ~5 hours. SP-A was added at various concentrations and changes in electrical impedance were measured over time. Impedance measurements, presented as a normalized “Cell Index,” are calculated as detailed (26 (link), 27 (link)). Under these conditions, a loss of Cell Index is associated with eosinophil detachment and cytotoxicity. Individual traces of cytotoxicity over time were averages of 2 – 3 technical replicates; standard deviations were eliminated for clarity. Quantification of cytoxicity was accomplished by measuring the area under the curve (AUC) after normalization of cell index. Graphical AUC measurements include baseline correction for untreated cells to best display changes.