Fig. 2

Endocytosis of LNP-mRNAs / EV-proteins for immune interaction. A Most of the internalized LNP-mRNAs will be shuttled to the lysosome and a small fraction will escape from the endosomes to release mRNA for protein translation. Some of the newly translated proteins could undergo degradation by the proteasome for MHC class I antigen presentation to CD8⁺ T cells Others could be displayed on the cell surface or secreted into the extracellular space. B The membrane-bound or secreted proteins when endocytosed by APCs will be processed in the lysosomes for MHC class II antigen presentation to CD4⁺ T cells. C Most of the internalized EV-proteins will be shuttled to the lysosome and a small fraction will escape from the endosomes to release protein for degradation by the proteasome and MHC class I antigen presentation to CD8⁺ T cells. D When EV-proteins are endocytosed by APCs, the poor endosomal escape enhances lysosomal processing of the proteins and facilitates MHC class II antigen presentation to CD4⁺ T cells. ER endoplasmic reticulum, TCR T cell receptor, APC antigen-presenting cell