MOESM2 of Prime-pull vaccination with a plant-derived virus-like particle influenza vaccine elicits a broad immune response and protects aged mice from death and frailty after challenge

Additional file 2: Figure S1. Flow cytometry-gating strategy for splenocytes. Aged (18–22 months) BALB/c mice were immunized twice with H1-VLP, split-virion vaccine or naïve. Three weeks post-boost (6–24 mice/group), splenocytes were collected and stimulated ex vivo for 18 h with H1-VLP.