Comparison of MTT colorimetric assay and tritiated thymidine uptake for lymphocyte proliferation assays using chicken splenocytes.

The MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) colorimetric assay was compared with the conventional tritiated thymidine deoxyriboside (3H-TdR) incorporation for assay of lymphocyte blastogenesis using mononuclear cells isolated from the spleens of specific-pathogen-free chickens. The study was undertaken in an effort to simplify methods for assessing avian lymphocyte proliferation, specifically for evaluating response to mitogens or for indirect measurement of T-cell growth factors. The results from stimulated cells in both assay methods were significantly different from results from the control cells, and the MTT assay results regressed in a significant linear manner on counts from 3H-TdR incorporation. On this basis, the MTT assay is a valid test for evaluation of lymphocyte proliferation of chicken splenocytes.