Fig. 2

Antigen presentation of cancer vaccines. Peptide vaccines: Synthetic long peptides (SLPs) and adjuvants, such as Toll-like receptor (TLR) agonists, are injected to stimulate an immune response. Antigen-presenting cells (APCs) take up SLPs, process them via cross-presentation pathways, and present peptide‒MHC complexes to T cells. Adjuvants activate APCs, increasing the expression of costimulatory markers such as CD80/86 and promoting their migration to lymph nodes, where they prime and activate T cells. mRNA vaccines: mRNA vaccines encoding tumor antigens are internalized by dendritic cells (DCs) via endocytosis or macropinocytosis, followed by endosomal escape and cytosolic release of mRNA facilitated by ionizable lipids. Within the cytoplasm, mRNAs are translated into antigens, which are subsequently processed into epitopes and presented on the cell surface through interactions with MHC molecules. During this process, the mRNA vaccine might activate innate immune pathways, including TLR7, MDA5, or RIG-1, thereby stimulating innate immune responses. These antigen-presenting DCs then prime antigen-specific T cells, which differentiate into either memory T cells or effector T cells, thereby inducing tumor cell death