Figure 2.

Priming with ganglioside-treated bone-marrow-derived dendritic cells (BMDC) inhibits the development of effector T cells. (a) Naive CD4⁺ T cells from B6 AND TCR transgenic mice were primed with 5 μg/ml MCC peptide presented by either untreated BMDC or BMDC pre-treated with the indicated concentration of GM1 ganglioside as described in Fig. 1 in the presence of exogenous interleukin-2 (IL-2; neutral conditions). After 4 days the T cells were harvested and equal numbers (5 × 10^5/ml) were re-stimulated with MCC peptide presented by T-cell-depleted spleen cells as antigen-presenting cells. Two days later supernatant was collected and the indicated cytokines were assayed by ELISA as described in Fig. 1. (b) B6 AND T-cell receptor T cells were stimulated as in (a) except exogenous IL-4 and anti-interferon-γ (IFN-γ) antibody was added during the priming phase of the culture to induce T helper type 2 (Th2) development (Th2 skewing conditions) and GD1a (50 μm) was used to treat the BMDC. The level of IL-4 produced under neutral conditions is below the level of detection in the ELISA. *P < 0·005 for all groups compared with control. These results are representative of more than three independent experiments for each cytokine.