Suppression of Experimental Allergic Encephalomyelitis in Lewis Rats by Administration of Gangliosides

Gangliosides (GA) are known to suppress T cell responses to mitogens and alloantigens. GA treatment (more than 50 mg/kg/rat subcutaneously every 12 hr) significantly suppressed clinical signs and histologic lesions of both actively induced and cell-transferred experimental allergic encephalomyelitis (EAE) in Lewis rats in a dose-dependent manner: P < 0.01, in actively induced EAE; P < 0.001 (100 mg/kg) or P < 0.005 (50 mg/kg), in cell-transferred EAE. Lymph node cells from guinea pig myelin basic protein (GPMBP)-sensitized rats were stimulated in vitro with the specific sensitizing antigen, GPMBP, or with Con A. Purified bovine brain GA significantly suppressed GPMBP-induced proliferation in a dose-dependent manner (P < 0.01). GA treatment during sensitization phase (from Day—5 to Day 4) did not suppress actively induced EAE. There were no significant differences in T cell subsets of peripheral blood or spleen cells between GA-treated rats and controls by flow cytometry analysis. Taken together, these findings indicate that GA primarily act on the immune effector phase of EAE.