On the suitability of the MTT-assay for the evaluation of mitogenic lymphocyte blastogenesis in swine.

Using swine peripheral blood lymphocytes, we examined the suitability of a colorimetric tetrazolium (MTT) reduction test for the evaluation of mitogenic lymphoblastogenesis in comparison to radiolabelling methods. In our study, we did not find a correlation between the 3H-thymidine- or 14C-thymidine uptake into DNA and the mitochondrial MTT cleavage activity, comparable to that formerly demonstrated for mouse cytotoxic T cells and for sheep peripheral blood lymphocytes. With the MTT assay, mitogen-driven lymphocyte activation was scarcely assessable, whereas a clear mitogenic response could be observed using radiolabelling methods. The results show that the MTT cleavage activity reflects quite a different state of cellular function than the DNA synthesis and that the evaluation of this activity is not suited to determining lymphocyte activation in swine as a measure of mitogenic response.