Production of interleukin 2 in serum-free medium.

The production of interleukin 2 by rat splenocytes, stimulated with Con A in serum-free medium, was studied. Under optimal conditions the stimulation in serum-containing and serum-free media resulted in identical interleukin 2 titers. The addition of phorbol myristate acetate prior or simultaneously with Con A did not augment interleukin 2 production. In contrast, preincubation of lymphocytes in serum-free medium for 24-36 hrs brought about a 8-10-fold increase of interleukin 2 titer. The interleukin 2 titer 4 hrs after the induction of preincubated lymphocytes with Con A was about 20% of maximal activity. The possible mechanism of early interleukin 2 production is under discussion.