USE OF A SIMPLE LIGHT ABSORBENCY ASSAY TO MEASURE LYMPHOCYTE-PROLIFERATION

The proliferative response of human lymphocytes to stimuli such as for eign histocompatibility antigens or mitogens is generally assessed by measuring the amount of tritiated thymidine which the cells incorporat e in culture. In this paper, the possibility of assessing lymphocyte p roliferation and viability by an empirical assay, using measurement of light absorbance on a ELISA reader in the yellow wave length (450 nm/ air-550 fun/air), has been studied. The correlation of these measureme nts with a colormetric viability assay using MTS/PMS, with tritiated t hymidine incorporation and with trypan blue exclusion viability counti ng, was determined. The results showed that the light absorbance assay correlate well with cell proliferation during 48-120 hours culture pe riod and with cell viability after a 72 hours culture period. The MTS/ PMS colormetric assay as well as trypan blue exclusion cell counting c onfirmed that the light absorbance assay was not merely caused by dead cells. This data confirm that the light absorbance assay is sufficien tly sensitive to low levels of proliferation to allow detection of suc h responses at least as effectively as thymidine incorporation. The li ght absorbance assay procedure avoids the expense, time and hazards as sociated with scintillation counting, and is simple to perform without the necessity for reagents and preparative steps required by other as says.