Modulation of experimental allergic encephalomyelitis (EAE): suppression of active reinduction of EAE in rats recovered from passively transferred disease.

Lewis rats that have recovered from EAE induced by the passive transfer of in vitro activated lymphocytes sensitized to myelin basic protein showed suppression upon subsequent active reinduction of EAE. This suppression was manifested during the early convalescent stage (up to 30 days after the primary cell transfer) and seemed to be acquired partly idiotype-specifically and partly idiotype-nonspecifically. The convalescent rats were fully susceptible to the transfer of sufficient numbers of effector cells, and they could induce pre-effector cells in response to the encephalitogen in vivo as effectively as in naive rats. This suppression was not transferred to naive rats by lymphoid cells from the convalescent rats. The mechanism of this suppression was thought to be a defect in expansion and/or differentiation of pre-effector cells to effector cells in the convalescent rats.