However, the lack of response to the E329–34315-mer observed in BALB/c mice immunized with DNA seemed to be partially because the same cells were able to respond to the minimum epitope within that sequence, as seen against the 9-mer E330–338. Our results also expanded the C57Bl/6 (H2b) epitope mapping for the envelope protein of the YF virus. Sequences E1–15 and E233–247 were previously described as containing CD8 and CD4 epitopes, respectively,however, we were able to identify several new epitopes, six for CD4 and four for CD8