Structure-Dependent Innate Immune Compatibility of Sup35 G7-Derived Self-Assembling Peptide Nanomaterials in an...

Self-assembling peptide nanomaterials are increasingly investigated as modular platforms for vaccine delivery and immune modulation. However, their structure-dependent interactions with immune cells remain insufficiently defined, limiting their early evaluation as peptide nanomaterial. This study evaluated the physicochemical properties and immunological effects of three Sup35 G7-derived self-assembling peptide nanomaterials, G7, G7d, and G7d(PEG)HER2, with particular attention to innate immune compatibility and macrophage responses.

The morphology and surface charge of the peptides were characterized by transmission electron microscopy and zeta-potential analysis. Their cytocompatibility was assessed in THP-1 macrophages, Jurkat T cells, and IM-9 B cells. Transcriptomic and proteomic analyses were integrated to identify immune-cell-specific molecular responses. Cellular uptake, apoptosis, cytokine secretion, and intracellular reactive oxygen species production were further examined in macrophages. In vivo immunization in BALB/c mice was conducted to assess systemic immunoglobulin responses.

G7 and G7d assembled into large crystalline aggregates with limited dispersibility, whereas PEGylated G7d(PEG)HER2 formed more uniform nanofibers. All three materials showed positive zeta potentials and relatively low cytotoxicity across the tested immune cell models. Among these cells, macrophages displayed the strongest molecular responses. Integrated transcriptomic and proteomic analyses revealed coordinated alterations mainly involving metabolic remodeling, redox homeostasis, proteasome activity, and mitochondrial-associated pathways, rather than predominant activation of classical pro-inflammatory signaling. Ultrastructural analysis confirmed intracellular uptake of assembled peptides and mitochondrial morphological changes without detectable apoptosis. Cytokine profiling showed reduced secretion of multiple cytokines and chemokines, while G7 induced higher intracellular reactive oxygen species than G7d and G7d(PEG)HER2. In vivo, G7d administration was associated with increased serum IgG levels, whereas G7 showed a moderate effect and G7d(PEG)HER2 exhibited minimal changes; IgM levels remained unchanged.

Sup35 G7 based self-assembling peptides exhibit low acute toxicity but induce structure-dependent modulation of macrophage function. Differences in assembly morphology and surface modification may influence systemic humoral responses. These findings support the importance of physicochemical design in evaluating immune compatibility of peptide nanomaterial scaffolds.