Effective induction of antigen-specific cytotoxic T lymphocyte responses requires delivery systems that enable both the intracellular delivery of peptide antigens to antigen-presenting cells and the intracellular release of antigen-derived species compatible with major histocompatibility complex (MHC) class I-mediated presentation. In this study, we synthesized three type of reduction-responsive self-assembling peptide, Cys-EG12, SS1-EG12, and SS2-EG12, which differ in the number and design of disulfide-containing linkages, and investigated how these structural differences affect nanofiber formation and antigen presentation. Thioflavin T assay, transmission electron microscopy, and circular dichroism measurements showed that EG12, SS1-EG12, and SS2-EG12 formed β-sheet-rich nanofibers, whereas Cys-EG12 formed particulate assemblies. Under reducing conditions, SS1-EG12 and SS2-EG12 nanofibers released epitope-containing fragments. Flow cytometry and confocal laser scanning microscopy confirmed cellular uptake of EG12, SS1-EG12, and SS2-EG12 nanofibers by JAWS II dendritic cells, although uptake of SS1-EG12 and SS2-EG12 was lower than that of EG12. Despite this lower uptake, JAWS II cells treated with SS2-EG12 nanofibers exhibited enhanced MHC class I-mediated antigen presentation compared with cells treated with EG12 and SS1-EG12 nanofibers. These findings suggest that designing disulfide linkages to enable the reductive release of epitope-containing species in a form more favorable for MHC class I-mediated presentation is an important strategy for antigen delivery systems based on self-assembling peptide nanofibers.
Waku et al. (2026) studied this question.