USE OF STREPTOKINASE AS A RECALL ANTIGEN FOR LYMPHOCYTE-PROLIFERATION TESTING INVITRO

The use of streptokinase (SK) as a recall antigen (Ag) for stimulation of human lymphocyte proliferation in vitro was evaluated. SK is a potent stimulant, inducing a greater response than three other Ags, tetanus toxoid, Candida albicans extract, or streptolysin. The optimum stimulatory concentration is 1000 U/ml, and peak stimulation occurs between days 6 and 8. Human cord-blood lymphocytes do not respond to SK, suggesting that it is an Ag and not a mitogen. The response rate in an adult population was 82%, higher than the rate of two other Ags tested (tetanus toxoid or Candida). These findings demonstrate the ability of SK to act as a potent recall Ag for human lymphocyte proliferation in vitro.