A sensitive method for the determination of cytolytic activity

A new method is described for the determination of the cytolytic activity of extremely low levels of stable as well as very labile cytotoxins. The method involves the application of the cytotoxin to a column of immunobilized erythrocytes or other suitable cells and a continuous monitoring of the column eluate for the presence of hemoglobin or other cell constituents. The cytotoxic activity of horseradish peroxidase at concentrations as low as 10^?12, m can be measured with this technique. The column hemolytic assay is compared with a static (batch) hemolytic assay with respect to sensitivity and reproducibility. Furthermore, a method is described to determine the true rates of lysis, i.e., the number of cells lysed per minute.