Immune responses to myelin basic protein in mycobacterial-induced suppression of experimental allergic encephalomyelitis

Abstract

Pretreatment of guinea pigs with complete Freund's adjuvant (CFA) 21 days prior to injection with myelin basic protein (BP) in CFA resulted in marked attenuation of clinical and pathologic manifestations of experimental allergic encephalomyelitis (EAE). Delayed hypersensitivity skin tests to homologous BP were likewise depressed in protected animals. The protected guinea pigs also demonstrated diminished in vitro reactivity to BP as assessed by BP-induced proliferative response of peritoneal exudate cells (PEC) and BP-induced inhibition of macrophage migration. Broad-based suppression of immunologic reactivity did not occur in these animals, as manifested by larger skin tests to PPD, a greater proliferative response to old tuberculin (OT), by PEC and peripheral blood lymphocytes (PBL), as well as marked PPD-induced inhibition of macrophage migration. Diminution of the degree of cell-mediated reactivity to BP may be one of the mechanisms by which prior treatment with CFA suppresses subsequent development of EAE.