Additional file 1: Figure S1. of Effect of a synbiotic on the response to seasonal influenza vaccination is strongly influenced by degree of immunosenescence

Effect of B. longum + Gl-OS on levels of vaccine-specific IgA, IgG1, IgD and IgM. Data are optical density units (OD450nm) ± 2 SEM, change from baseline (week 4) for n = 54–58 subjects per group, 2 (week 6) and 4 (week 8) weeks after vaccination. ☐ Maltodextrin, (gray square) B. longum + Gl-OS. Data were analysed using a Linear Mixed Model (LMM) with fixed factors of time, age and treatment. For IgA (plot A), there was a significant effect of age (p < 0.001) and time (p < 0.001) and a significant age*time interaction (p < 0.001). Data split by cohort showed a significant effect of time in both the young (p < 0.01) and older (p < 0.001) cohorts. For IgG1 (plot B), there were significant effects of time (p < 0.001) and age (p < 0.001). Data split by cohort showed a significant effect of time (p < 0.001) and a trend for a treatment effect (p = 0.03) in the older cohort, and a significant effect of time (p < 0.001) in the young cohort. For IgD (plot C), there were significant effects of age (p < 0.001) and time (p < 0.001) for the combined cohorts and a significant effect of time in both the young (p < 0.001) and older cohorts (p < 0.001) when considered separately. For IgM (plot D), there was a significant effect of time (p < 0.001), but no effect of age or treatment. (DOCX 52 kb)