Figure 6.

The effects of 1-methyl-d-l-tryptophan (1-MT) on the induction of an hepatitis B virus surface antigen (HBsAg) -specific immune response. (a) Wild-type (WT) mice received 1-MT orally at a dose of either 0 or 5 mg/ml in drinking water 2 days before the immunization to 7 days after the immunization. Splenocytes from these mice were isolated 7 days after the immunization. These cells were stimulated ex vivo with the HBsAg S_28–39 peptide and monitored for interferon-γ-secreting cells by means of an ELISPOT assay. The results are shown as mean ± SEM (four or five mice/group) for three independent experiments. (b) Induction of HBsAg-specific CD8⁺ T cells was assessed by means of flow cytometric analysis using fluorescent dimeric H-2L^d-HBsAg S_28–39 complexes (DimerX). FACS profiles are shown for WT mice and for 1-MT-treated WT mice after the inoculation with HBsAg and α-galactosylceramide (α-GalCer). (c) Quantitative data on the frequency of dimeric H-2L^d-HBsAg-positive cell populations (mean ± SEM, n = 4). *Statistically significant differences.