Modulation of experimental allergic encephalomyelitis with anti-T suppressor factor antibodies.

mAb reactive with T suppressor factors (TsF) were used to alter the course of myelin basic protein-induced experimental allergic encephalomyelitis in (SJL/J x PL/J)F1 mice. In vivo administration of mAb 14-12, reactive with effector TsF, exacerbated the clinical expression of encephalomyelitis as evidenced by prolonged periods of total limb paralysis in affected animals. This aggravation of disease signs is probably related to the inhibition of effector Ts function by mAb 14-12 thus allowing T cell autoreactivity to proceed unchecked. Disease course was influenced more favorably by i.v. administration of mAb 14-30 reactive with a subset of inducer TsF. Ten days of treatment with this mAb resulted in a reduction in the incidence and severity of disease, noted as the development of minimal limb weakness but no paralysis in the majority of affected animals. Adoptive transfer experiments revealed the presence of Ag-specific Ts in mAb 14-30-treated mice that inhibited recipient Lyt-1+ responses to myelin basic protein, the immunizing autoantigen. Suppression by transferred Ts was revealed only by treatment of the donor population with anti-Lyt-1.2 plus C, however, indicating a role for contrasuppressor activity in the regulation of autoimmune T cell function. Results are considered relevant to the potential for immunotherapeutic management of multiple sclerosis in man.