Abstract
A rapid colorimetric assay using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) was applied to evaluate equine lymphocyte blastogenic response to mitogens. The optimum concentrations of concanavalin A (Con A), phytohemagglutinin-P (PHA) and pokeweed mitogen (PWM) were 5 μg/ml, 2.5 μg/ml, and a 1:80 dilution, respectively, when lymphocytes were cultured at a concentration of 1 × 106 cells/ml for 5 days in a 96-well microplate. Significant correlations between the results obtained by the MTT assay and the 3H-thymidine incorporation assay were observed. The correlation coefficients were 0.727 (n=68), 0.692 (n=57), and 0.681 (n=44), when lymphocytes were stimulated with Con A, PHA, and PWM, respectively. The MTT assay may be simple and reliable for studying equine cellular immune functions and a suitable alternative to conventional assay systems using radioactive materials.
