Induction of cellular immunity by intradermal immunization with HTLV-1/HBc chimeric particle. Mice were immunized twice with recombinant HTLV-1/HBc chimeric particle, HTLV-1 peptide and HTLV-1 peptide + HBc particle. The number of IFN-□-producing cells was measured by ELISPOT assay. IFN-□ spots show the number of peptide-loaded target cells to peptide-unloaded target cells. *P<0.05, **P<0.01 vs PBS group. The experiments were performed in triplicate. Mean S.E. are shown in the results.