[Changes in the expression of HLA-antigens on lymphocytes after certain types of treatment]

The microlymphocytotoxic test was used for typing HLA-A and HLA-B antigens of peripheral blood lymphocytes in normal subjects. Cultivation of lymphocytes for 72 hours signifies that distinct reaction with the cells is produced by a greater number of HLA-antisera, with the specificity of direct and cross reactions being unchanged. Addition of mitogens to the cultural medium further increases the number of reacting antisera. The treatment of lymphocytes with cyclophosphan (an activated form) in doses not leading to the dealth of the cells but inhibiting cells proliferation completely eliminates the above effect. Stimulation of such cultures with mitogens did not entail the increased number of positive reactions. Possible mechanisms of the phenomenon under consideration are discussed.