Objective:To compare the optimal experimental condition and different sensitivity in murine lymphocyte proliferation response as measured by thiazolyl blue(MTT)and cell counting kit-8(CCK-8)assays.Method: Spleen lymphocytes were isolated from mice,and subsequently lymphocyte proliferative activities were compared with different culture intervals,dosages,and cell counts,respectively.Results:For 2×10~5 lymphocytes reaction system,the best incubation time of MTT was 71 hours,and the best reaction dose was 15μl.For CCK-8 assay, the best incubation time of CCK-8 was 72 hours,and reaction dose was 10 pi.In addition,by comparing the proliferative activities measured by the two different methods for the same cell culture system,it was shown that the sensitivity of CCK-8 assay was much higher than that of MTT assay.Conclusion:CCK-8 assay appears to be a better method for measurement of lymphocyte proliferation response in mice.