Detection of the lethal effects of T-2 mycotoxin on cells using a rapid colorimetric viability assay

A colorimetric method of determining cell viabilities in cultured cells is described. The system is based on the ability of mitochondrial enzymes in live but not dead cells to chemically reduce a tetrazolium salt (MTT) into a colored formazan dye which can be detected at 570 nm using a multiwell scanning spectrophotometer. 48 h Chinese hamster ovary (CHO) cell cultures are used in the assay and the amount of colored product formed is directly proportional to cell number over a range of 0.39-12.5 X 10(4) cells/ml. The cytotoxic effects of T-2 mycotoxin can also be detected colorimetrically using this method. The toxin dose which inhibits formazan formation (50% endpoint = 14-16 ng/ml) is very comparable to that which inhibits cell viability (17 ng/ml), or protein and DNA synthesis (10 ng/ml). This system also works well with mitogen-stimulated primary lymphocyte cultures but these cells exhibit a much more sensitive response to T-2 effects having a 50% inhibition endpoint of 2 ng/ml. The assay is rapid to perform and gives a high degree of precision and could serve as a valid alternative to viability assays currently in use.