(a) Chemical structures of polypeptides with side chains of different lengths. P1 induced (b) ER stress and (c) mtDNA release in BMDMs more strongly than did P3 (mid-length) and PS (short length) (n=3, mean±SD), ordinary one-way ANOVA. P1 improved (d) phagocytosis of EO771 breast cancer cells and (e) cross-presentation of the model antigen SIINFEKL-H2Kb to a greater extent than did P3 and P1 (n=3, mean±SD), ordinary one-way ANOVA. (f) Expression of genes for pro-inflammatory cytokines was affected by the length of side chains in the polypeptides (n=3, mean±SD), ordinary one-way ANOVA.