Liposome-associated ganglioside antigens (ganglioside GM1 or bovine brain gangliosides) were prepared to facilitate the potential protective efficacy for Trypanosoma brucei . Mice were immunized with liposome-associated ganglioside GM1 or bovine brain gangliosides intraperitoneally (i.p.). After immunization, significantly higher antigen-specific IgG and IgM antibodies were detected in sera than in the nonimmunized control group. When sera from immunized mice were analyzed for isotype distribution, antigen-specific IgG1, IgG2a, and IgG3 antibody responses were also noted. After immunization, mice were challenged i.p. with 1 × 10 2 cells of T. brucei . Sixty percentage of liposome-associated ganglioside GM1–immunized mice survived the infection, and all the mice immunized with bovine brain gangliosides–containing liposomes survived. However, all control mice died within 7 days after infection. These data demonstrate that liposomes containing ganglioside antigens have the potential usefulness for the induction of a protective immune response against T. brucei infection and suggest the possibility of developing vaccines that may ultimately be used for the prevention of trypanosomiasis.

Gangliosides were isolated from Trypanosoma brucei and analyzed by thin-layer chromatography (TLC) and TLC immunostaining test. Four species of gangliosides, designated as G-1, G-2, G-3, and G-4, were separated by TLC. G-1 ganglioside had the same TLC migration rate as GM3. In contrast, G-2, G-3, and G-4 gangliosides migrated a little slower than GM1, GD1a, and GD1b, respectively. To characterize the molecular species of gangliosides from T. brucei , G-1, G-2, G-3, and G-4 gangliosides were purified and analyzed by TLC immunostaining test with monoclonal antibodies against gangliosides. G-1 ganglioside showed the reactivity to the monoclonal antibody against ganglioside GM3. G-2 was recognized by the anti-GM1 monoclonal antibody. G-3 showed reaction with the monoclonal antibody to GD1a. G-4 had the reactivity to anti-GD1b monoclonal antibody. Using 4 kinds of monoclonal antibodies, we also studied the expression of GM3, GM1, GD1a, and GD1b in T. brucei parasites. GM3, GM1, GD1a, and GD1b were detected on the cell surface of T. brucei . These results suggest that G-1, G-2, G-3, and G-4 gangliosides are GM3 (NeuAcα2-3Galβ1-4Glcβ1-1Cer), GM1 (Galβ1-3GalNAcβ1-4[NeuAcα2-3]Galβ1-4Glcβ1-1Cer), GD1a (NeuAcα2-3Galβ1-3GalNAcβ1-4[NeuAcα2-3]Galβ1-4Glcβ1-1Cer), and GD1b (Galβ1-3GalNAcβ1-4[NeuAcα2-8NeuAcα2- 3]Galβ1-4Glcβ1-1Cer), respectively, and also that they are expressed on the cell surface of T. brucei .