Self-Assembly of Block Heterochiral Peptides into Helical Tapes.

Patterned substitution of d-amino acids into the primary sequences of self-assembling peptides influences molecular-level packing and supramolecular morphology. We report that block heterochiral analogs of the model amphipathic peptide KFE8 (Ac-FKFEFKFE-NH), composed of two FKFE repeat motifs with opposite chirality, assemble into helical tapes with dimensions greatly exceeding those of their fibrillar homochiral counterparts. At sufficient concentrations, these tapes form hydrogels with reduced storage moduli but retain the shear-thinning behavior and consistent mechanical recovery of the homochiral analogs.

Nanoscale Peptide Self-assemblies Boost BCG-primed Cellular Immunity Against Mycobacterium tuberculosis.

Bacillus Calmette-Guerin (BCG) is the only vaccine against TB and has limited protection efficacy, which wanes past adolescence. Multifunctional CD8+ T cells (IFN-γ+/TNF-α+/IL-2+) are associated with lower reactivation risk and enhanced control of active Mtb infection. Since boosting with BCG is contraindicated, booster vaccines that augment T cell immunity in the lungs of BCG-vaccinated individuals are urgently needed.

Supramolecular Peptide Nanofibers Engage Mechanisms of Autophagy in Antigen-Presenting Cells.

Supramolecular peptide nanofibers are attractive for applications in vaccine development due to their ability to induce strong immune responses without added adjuvants or associated inflammation. Here, we report that self-assembling peptide nanofibers bearing CD4+ or CD8+ T cell epitopes are processed through mechanisms of autophagy in antigen-presenting cells (APCs). Using standard in vitro antigen presentation assays, we confirmed loss and gain of the adjuvant function using pharmacological modulators of autophagy and APCs deficient in multiple autophagy proteins.