MHC-I antigen cross-presentation (B3Z assay) by EL4 lymphoma cells for Ap-containing AcDEX NPs and PLGA NPs. In vitro CTL activation study of B3Z T cells co-cultured with EL4 cells treated with free Ap, Ap-AcDEX1 NPs, Ap-AcDEX2 NPs, Ap-AcDEX3 NPs, Ap-PLGA NPs or Ap mixed with empty AcDEX2 NPs. The error bars show the standard error of the mean (s.e.m.) of three replicates. *p < 0.05, ***p < 0.001. The p values are analyzed by two-way ANOVA (Bonferroni post-test) with GraphPad Prism.