Gamma interferon production by different populations of human splenic lymphocytes

The treatment of cultures of human splenic lymphocytes with Staphylococcal enterotoxin A (SEA) resulted in the production of human gamma interferon (HuIFN-gamma). Separation of lymphocyte populations to give preparations enriched in T or B lymphocytes after removal of macrophages demonstrated that maximum IFN titers were detected when T lymphocytes were incubated with macrophages for a period of three days. The levels of IFN-gamma varied from donor to donor but the kinetics of induction were quite similar in all cases. Concentrations of 0.5-1.0 microgram/ml SEA gave optimal induction of IFN and the addition of thymosin alpha-1 at 10 micrograms/ml to the culture medium enhanced IFN-gamma production.