Figure 2.

SFVeE6,7 tattoo injections induce strong T cell responses. Mice were tattooed or intramuscularly immunized with 5 × 10⁶ i.u. of SFVeE6,7 and boosted 14 days later using the same or alternative delivery route. Ten days after the booster immunization animals were sacrificed. Freshly isolated (a) and 7-day in vitro restimulated spleen cells (b) were stained with MHC class I tetramers and anti-CD8 antibodies and analyzed by flow cytometry. The percentages of tetramer-positive cells within the CD8 T cells are shown. Activity of restimulated spleen and inguinal lymph node cells were analyzed in regular (c); only spleen cells) and micro CTL assay (d; both spleen and lymph node cells). The frequencies of IFNγ-producing cells, both in the spleens and inguinal lymph nodes, were determined using Elispot assay. Results are expressed as number of IFNγ-producing cells per 10⁶ splenocytes (e) or per 10⁶ lymph node cells (f). Each dot represents an individual mouse; a–d—data from a representative experiment out of four (three mice/group); e—pooled data from four experiments; f—data from one experiment. E:T ratio—effector:target ratio. * p < 0.05 as compared with the im group.