Abstract

A tetrazolium salt has been used to develop a quantitative colorimetric assay for mammalian cell survival and proliferation. The assay detects living, but not dead cells and the signal generated is dependent on the degree of activation of the cells. This method can therefore be used to measure cytotoxicity, proliferation or activation. The results can be read on a multiwell scanning spectrophotometer (ELISA reader) and show a high degree of precision. No washing steps are used in the assay. The main adavantages of the colorimetric assay are its rapidly and precision, and the lack of any radioisotope. We have used the assay to measure proliferative lymphokines, mitogen stimulations and complement-mediated lysis.

Introduction

Many biological assays require the measurement of surviving and/or proliferating mammalian cells. This can be achieved by several methods, e.g., counting cells that include/exclude a dye, measuring released 5aCr-labeled protein after cell lysis, and measuring incorporation of radioactive nucleotides ([3H]thymidine or [lZSI]iododeoxyuridine) during cell proliferation. The radioactive method can be partially automated and can handle moderately large numbers of samples, but even with these methods, it is difficult to process thousands of assay points per day. In our current research we assay many samples of various lymphokines that induce cell proliferation, and so we required a rapid and quantitative assay capable of handling large numbers of samples.