Figure 3.

NA-specific T cell responses are detected early after immunization with MHC class II-targeted heterodimeric DNA vaccines

(A) BALB/c mice were vaccinated once i.m./EP with 5 μg of each A and B plasmids (10 μg total) encoding the indicated heterodimeric A/B vaccines (box). Draining lymph nodes (dLNs) and/or spleens were harvested as shown. (B–G) IFNγ-secreting spot-forming cells (SFCs) reactive to MHC class I-restricted (D^d, K^d) or MHC class II-restricted (I-E^d, I-A^d) peptides from NA^PR8 (B–D) or HA^PR8 (E–G) were measured by ELISpot on single-cell suspensions from dLNs on day 5 (B and E) or day 12 (C and F) or from spleens on day 12 (D and G). n = 6 mice/group; individual mice and mean ± SEM are indicated. ∗p ≤ 0.05, ∗∗p ≤ 0.01, ∗∗∗p ≤ 0.001; multiple-comparisons one-way ANOVA with Tukey’s correction.