Regulation of experimental allergic encephalomyelitis. Part 4. Further characterization of postrecovery suppressor cells.

Suppressor cells that regulate experimental allergic encephalomyelitis (EAE) are present in lymph nodes of Lewis rats that have recovered from the disease, as demonstrated by adoptive transfer of suppression for at least 108 days following challenge of donor rats with myelin basic protein (BP) in complete Freund's adjuvant (CFA). These suppressor lymph node cells (LNC) inhibit the occurrence of active, but not passive EAE in recipients, suggesting that they function early in the inductive phase of the response to BP. The suppressor cells are nylon-adherent, and suppression can be partially abrogated by depletion of B cells with anti-immunoglobulin (ig) and complement (C). Serum from recovered donors has, at best, only a modest suppressive effect when transfused into syngeneic recipients. These findings suggest that the B cells do not mediate suppression on EAE via production of blocking antibody, but may function directly, perhaps by triggering T cells to become suppressor cells.