<正>Objective:With the regular mixed lymphocytes culture （MLC） to detect the allograft rejection

the reactivity of the activated lymphocytes （primed lymphocytes） of a recipient shows sometimes increase and sometimes decrease against the antigens from the donor

which is inconsistent with the clinical results. In order to establish a convenient method for testing the specificity of the activated lymphocytes in vitro

so as to know the rejection occurred or not by testing the existence of the specific activated lymphocytes against donor’s HLA antigens in the recipient’s peripheral blood. Methods: Anti-IL-2 neutralizing monoclonal antibody （anti-IL-2 N-mAb） and immunosuppressors were introduced in this test system in the presence of specific stimulators and activated lymphocytes. Results: When the activated lymphocytes were chosen from the one-way MLC 4 d to undergo re-stimulation by specific stimulators

the activity of activated lymphocytes in the treatment group was suppressed significantly compared with that in the control group. The result of this test method is consistent with the biopsy in the clinical diagnosis of rejection. Conclusion:It suggests that the activated lymphocytes can be inactivated by specific antigens in certain conditions. This can be a useful tool to define the specificity of the activated lymphocytes.