Suppressor cells generated in mice late after thermal injury.

A second suppressive state (S-SupS) in interferon (IFN) response was demonstrated when mice with third-degree burns of approximately 30% of the body surface area (TI-mice) were stimulated in vivo by Staphylococcal enterotoxin A, a gamma IFN inducer. The first suppressive state in IFN production, appearing 3 to 7 days after thermal injury, was mediated by the generation of splenic suppressor macrophages. The S-SupS was demonstrated approximately 3 weeks post thermal injury. It persisted for almost 3 weeks and gradually disappeared by 7 weeks. Spleen cells from mice during the S-SupS produced less IFN in vitro than normal mouse splenic mononuclear cells (MNC) when stimulated with concanavalin A (Con A). Splenic MNC of mice during the S-SupS inhibited IFN production when they were co-cultured with normal mouse splenic MNC in the presence of Con A. Since this suppressor cell activity could not be removed from TI-mice splenic MNC by carbonyl iron treatment, or by a technique of adherence to a plastic surface, it is suggested that two different cell populations which are capable of suppressing the IFN response of TI-mice exist at different time periods following burn injury.