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Biomaterials

A Supramolecular Peptide Nanofiber Active Immunotherapy against IL-22 Binding Protein for Intestinal Regeneration in Inflammatory Bowel Disease

(C-98) A Supramolecular Peptide Nanofiber Active Immunotherapy against IL-22 Binding Protein for Intestinal Regeneration in Inflammatory Bowel Disease

Thursday, October 12, 2023

9:30 AM – 10:30 AM PDT

Location: Exhibit Hall - Row C - Poster # 98

Presenting Author(s)

Deleah Pettie (she/her/hers)

Graduate Student
Duke University
Durham, North Carolina, United States

Co-Author(s)

Yaoying Wu

Assistant Professor of Biomedical and Chemical Engineering
Syracuse University, New York, United States

Primary Investigator(s)

Joel Collier

Professor of Biomedical Engineering
Duke University, North Carolina, United States

Introduction:: Current treatments for Inflammatory Bowel Disease (IBD) consist of anti-inflammatory drugs, immunosuppressants, and biologics against inflammatory cytokines. These treatments cause increased risk of infection due to immune suppression, only focus on treating inflammation, and do not promote intestinal epithelial regeneration. As an alternative, active immunotherapies are receiving increased interest and aim at reducing inflammation and promoting intestinal healing within broad populations. An active immunotherapy made from engineered immunogens can generate antibodies that help anti-inflammatory responses and promote intestinal regeneration. Supramolecular assemblies of proteins and peptides combined with B- and T-cell epitopes can form nanomaterials that raise antibody responses. Coil29 is an alpha helical peptide platform that oligomerizes into supramolecular nanofiber immunogens. This work describes the design of an active immunotherapy using Coil29 against Interleukin-22 binding protein (IL-22BP), a critical mediator in IBD. IL-22BP is a regulator of IL-22 which promotes cellular proliferation and inhibition of apoptosis. The central hypothesis is that antibody responses against IL-22BP can promote IL-22 regeneration of the intestinal epithelial layer in a chronic colitis mouse model.

Materials and Methods::

Kolaskar Tongaonkar antigenicity testing was used to predict B-cell epitopes within mouse IL-22 binding protein, and these peptides were synthesized in tandem with Coil29 self-assembling peptides to make immunogens. Four predicted IL-22 binding protein epitopes with a linker were synthesized onto Coil29. Peptides were synthesized using Fmoc solid phase peptide synthesis using a CEM Liberty Blue peptide synthesizer. Peptides were purified by HPLC and molecular weights were confirmed with MALDI. IL-22 binding protein Coil29 peptides were co-assembled in a 1:1 ratio with unmodified Coil29. The peptides were heated in acetate buffer pH 4 to 95 ℃ and cooled, then suspended in PBS. Nanofiber formulations were assessed for fibrilization using Atomic Force Microscopy.

To test immunogenicity,female C57BL/6 mice (n=5 per group) were subcutaneously immunized with 100 mL of 2 mM peptide and boosted twice (0, 3, 5 weeks). A control group was also subcutaneously immunized with Coil29 lacking any IL-22BP epitopes. Sera were collected at weeks 0, 2, 4, and 6, and probed against biotinylated IL-22BP epitopes and whole IL-22 binding protein via indirect ELISA.

Results, Conclusions, and Discussions:: Coil29 peptides bearing four different IL-22BP epitope candidates (IL-22BP-A, B, C, D) formed nanofibers with expected morphologies by AFM (Figure 1), so these progressed into a mouse study to assess immunogenicity. Mice immunized with IL-22BP Coil29 candidates began to exhibit significant increases in anti-IL-22BP antibody responses (titer and AUC) by about week 4 and steadily increased thereafter (Figure 2). Mice immunized with unmodified Coil29 maintained baseline titers and AUC. Mouse serum was also assessed for antibody responses against whole IL-22 binding protein. The IgG titer and AUC responses against IL-22BP were close to baseline for weeks 0 and 2 with a slight increase for weeks 4 and 6 for mice immunized with IL-22BP epitope Coil29. These studies showed that predicted IL-22BP epitopes can be synthesized onto supramolecular peptide platform Coil29 and form nanofiber structures that raise IgG antibodies against the predicted epitopes and slight increase in IgG responses against IL-22 binding protein in mice. Future studies will be performed to optimize the IL-22BP Coil29 nanofibers to promote higher quality antibody responses against the whole IL-22 binding protein. This could be accomplished by exploring different adjuvants and routes of delivery to promote the desired antibody responses and increase production of CD4+ T cells with anti-inflammatory phenotypes. Once the nanofiber formulations are optimized, future studies will be performed to assess the intestinal regenerative properties of the active immunotherapy in a colitis mouse model. If successful, this work will be a proof-of-concept for an active immunotherapy that both reduces inflammation and promotes tissue regeneration in IBD. This work is innovative due to the use of modular supramolecular nanofibers that enable immunization against multiple targets within one formulation.

Acknowledgements (Optional): : This research has been supported by a grant from the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health under award number R21EB033687

References (Optional): :