2,3,5-Triphenyl tetrazolium chloride (TTC) reduction as exponential growth phase marker for mammalian cells in culture and for myeloma hybridization experiments.

Triphenyl tetrazolium chloride in vitro reduction by cells produces a red formazan pellet which can be extracted and measured. We have shown that such reduction is associated with animal cell growth, and particularly with the specific growth rate, so the measurement of Triphenyl tetrazolium chloride reduction is proposed as a physiological marker of the exponential growth of cultured cells. Further application of this technique is shown using this Redox reaction for estimating plasmacytoma fusion potential for hybridoma cell line production.