Figure 3

Cytolytic DNA immunisation enhances antigen presentation to CD8⁺ T cells in a time-dependent manner in vivo. (A) C57BL/6.SJL mice were immunised via the ID route with 100 μg of NS3-12del PRF (n = 7), OVA-12del D483A PRF (n = 14) or OVA-12del PRF (n = 14) prior to i.v. transfer of 30 μM CFSE-labelled C57BL/6 OT-I cells (5 × 10⁶ cells/recipient) 7 days later. 15 days after the i.v. transfer, proliferation of OT-I CD8⁺ cells was measured in the CLN and spleens of recipient mice. As a positive control, one day after the adoptive transfer of OT-I cells into naïve recipient mice (n = 2), 20 μg SIINFEKL peptide + 5 μg of LPS were injected ID per mouse prior to analysis 14 days later. Representative dot plots gated on CD8⁺ CD45.2⁺ T cell receptor (TCR) Vβ5.1/5.2⁺ are shown. The numbers in the gates indicate the percentage of lymphocytes that are single cells (doublet discriminated), CD8⁺ CD45.2⁺ TCR Vβ5.1/5.2⁺ with reduced levels of CFSE. (B) Mean + SEM of the percentages indicated in A (left panel) and the mean + SEM of the absolute number of CD8⁺ CD45.2⁺ TCR Vβ5.1/5.2⁺ CFSElo cells (right panel). Pooled data from two independent experiments are shown. The Kruskal-Wallis H test was used to determine the statistical significance of the data.