RESUMO
T4 cells were isolated twice separately from peripheral blood of the same donor.After activation by lectin,the isolated cells were culturedwith the medium containing self-made IL-2 for a long period.The culturedcells were identified for OKT antigens by immuno-fluorescent technique onday 10 and 22 of the cultivation,and the appearance of both T4 and T8antigens on the same cell (double marker cell)could be detected in about60-80%of cultured cells.The double marker T cells decreased in numberand the percentage of single marker T cells,either T4 or T8 cells,increasedgradually along with the cultivation.The function of double marker T cellswere investigated and the suppressor activity of these cells on PWM indu-ced antibody production response by cooperation between B cells and fresh T4cells was found.These results suggest that human peripheral blood T4 andT8 cells are not terminaly differentiated cells,because T4 and T8 antigencan be coexpressed on the same cell during the earlier cultivation.Afterlong period of activation,T4 and T8 double marker cells may change intoeitherT4 or T8 cells.