Activation of human lymphocytes by antigen stimulation
Previous studies have indicated that certain monoclonal antibodies (mAbs) against human CD3 can activate T cells and induce the T cell proliferation. According to Schwinzer´s protocol [17], human peripheral blood lymphocytes (HPBLs) were stimulated by immobilized anti-human CD3 mAb (OKT3, IgG2a) (Thermo Fisher Scientific, USA). Briefly, each of 100 µL PBS with 2 μg/mL anti-CD3 mAb (stimulated group) or without antibodies (PBS, as negative control) were immobilized in a well of 96-well plates overnight. After removal of PBS buffer, 200 µL lymphocyte culture including 2×105 fresh isolated lymphocytes in RPMI-1640 growth medium (supplemented with 10% FBS, 100 μg/mL streptomycin and 100 UI/mL penicillin) were cultured directly in each well of the 96-well plate with or without immobilized antibody at 37°C in a humidified atmosphere with 5% CO2 for 72 h.