Lymphoblastic transformation assay of sheep peripheral blood lymphocytes: a new rapid and easy-to-read technique.

A new micro-method was used to evaluate in vitro sensitivity of ovine peripheral blood lymphocytes (PBL) to different non specific mitogens (pHA, Con A, PWM) and to investigate the interest of a colorimetric assay for measurement of transformed lymphocytes. The results showed that sheep PBL in flat-bottomed microplates responded optimally at a cell density of 8 X 10(6) cells/ml to PHA (2.5 micrograms/ml), Con A (5 micrograms/ml) and PWM (5 micrograms/ml). The colorimetric assay using a tetrazolium salt (MTT), for measuring the transformed lymphocytes, is very well correlated with the classical method of [3H]thymidine incorporation. This new revelation technique of the mitogenic response improve the technical value of the assay, which is more rapid and easy-to-read, without diminishing the biological value.