Fig. 2. Identification of DENV-derived epitopes recognized by CD4⁺ T cells.

IFNγ ELISPOT was performed using CD4⁺ T cells isolated from DRB1*0101 transgenic IFN-α/βR^−/− (black bars) and IFN-α/βR^+/+ (white bars) mice. Mice were infected retro-orbitally with 1×10¹⁰ GE of DENV2. Seven days post-infection, CD4⁺ T cells were purified and tested against a panel of DENV2 predicted peptides. The data are expressed as mean number of SFC/10⁶ CD4⁺ T cells of two independent experiments. Error bars represent SEM. Responses against peptides were considered positive if the stimulation index (SI) exceeded double the mean negative control wells (effector cells plus APCs without peptide) and net spots were above the threshold of 20 SFCs/10⁶ CD4⁺ T cells in two individual experiments. Asterisks indicate peptides, which were able to elicit a significant IFNγ response, according to the criteria described above.