Biotin Functionalized Self-Assembled Peptide Nanofiber as an Adjuvant for Immunomodulatory Response.

The design and development of novel adjuvants, which enhance, accelerate, and prolong the immune responses triggered by antigens, hold great importance for targeting infectious diseases and cancer. Here, we designed a biotinylated peptide amphiphile (Biotin-PA) nanofiber, which serves as a noncovalent binding location for antigens. We showed that presenting the antigens on synthetic Biotin-PA nanofibers generated a higher immune response than the free antigens delivered with a CpG ODN (TLR9 agonist) adjuvant. Antigen attached Biotin-PA nanofibers triggered splenocytes to produce high levels of cytokines (IFN-γ, IL-12, TNF-α, and IL-6) and to exhibit a superior cross-presentation of the antigen. Both Biotin-PA nanofibers and CpG ODN induce a Th-1-biased IgG subclass response; however, delivering the antigen with Biotin-PA nanofibers induced significantly greater production of total IgG and subclasses of IgG compared to delivering the antigen with CpG ODN. Contrary to CpG ODN, Biotin-PA nanofibers also enhanced antigen-specific splenocyte proliferation and increased the proportion of the antigen-specific CD8(+) T cells. Given their biodegradability and biocompatibility, Biotin-PA nanofibers have a significant potential in immunoengineering applications as a biomaterial for the delivery of a diverse set of antigens derived from intracellular pathogens, emerging viral diseases such as COVID-19, or cancer cells to induce humoral and cellular immune responses against the antigens. This article is protected by copyright. All rights reserved.