Abstract for CytoTox 96^® Non-Radioactive Cytotoxicity Assay

Part# TB163
Printed in USA. Revised 3/09.
Instructions for Use of Product G1780.

The CytoTox 96^® Non-Radioactive Cytotoxicity Assay is a colorimetric alternative to ⁵¹Cr release cytotoxicity assays. The CytoTox 96^® Assay quantitatively measures lactate dehydrogenase (LDH), a stable cytosolic enzyme that is released upon cell lysis, in much the same way as ⁵¹Cr is released in radioactive assays. Released LDH in culture supernatants is measured with a 30-minute coupled enzymatic assay, which results in the conversion of a tetrazolium salt (INT) into a red formazan product. The amount of color formed is proportional to the number of lysed cells. Visible wavelength absorbance data are collected using a standard 96-well plate reader. Methods for determining LDH using tetrazolium salts in conjunction with diaphorase or alternate electron acceptors have been used for several years. Variations on this technology have been reported for measuring natural cytotoxicity and have been demonstrated to be identical (within experimental error) to values determined in parallel ⁵¹Cr release assays.