Peptide-Based Multiepitopic Vaccine Platforms via Click Reactions

Abstract

Multimeric antigen display and high overall valency are increasingly regarded as strategic goals for potent and broadly efficacious synthetic vaccines with potential market prospects. Herein, a modular and versatile approach to multifunctional peptide-based vaccine platforms at multimilligram scale in reasonable yields is reported. Preparation of chemoselectively modified peptide building blocks of medium-to-large size, conjugation of these subunits, and final assembly were achieved by a combination of Michael-type thiol–ene addition and copper­(I)-mediated alkyne–azide cycloaddition. The size and structural complexity of the building blocks required exploration of a further level of orthogonality, namely furan/maleimide Diels–Alder chemistry. After process optimization, a finely tuned, stepwise click approach has emerged as a workable, on-demand strategy to create macromolecular therapeutic vaccine assemblies.

Designing Functionally Versatile, Highly Immunogenic Peptide-Based Multiepitopic Vaccines against Foot-and-Mouth Disease Virus

“…A further step into chemically well-defined, single molecule vaccine platforms displaying a high number of relevant peptide motifs arranged in a dendrimeric fashion was devised by tail-to-tail fusion of two B 2 T maleimide subunits via orthogonal chemical ligation by copper(I)-catalyzed azide–alkyne 1,3-cycloaddition (CuAAC), leading to a novel B 2 T-TB 2 multivalent platform [ 37 ] ( Figure 1 C). Our synthesis strategy involved preparation of functionalized peptide building blocks based on the B 2 T(mal) predecessor but with site-specific modifications such as an extra C-terminal functionalization of the T-cell epitope with either azide- or alkyne-containing non-canonical amino acids to enable final subunit assembly.…”

“…In this study we have assessed the close relationship between dendrimer architecture and biological response in a realistic infectious disease scenario by means of in vivo animal studies with multi-epitope peptide vaccines against FMDV. We have also reported on the main aspects [discussed in further detail in [37]] of the refinement of our synthetic methodologies and their biological impact. Specifically, dendrimers bearing same B-and T-cell epitopes from FMDV O UKG/11/2001 (an isolate belonging to FMDV/Type O/PanAsia-1 topotype responsible for the pandemic in Asia, extended to parts of Africa and Europe in 1998-2001), in different arrangements and made by diverse conjugation approaches, were explored in search of an improved FMDV vaccine candidate.…”

“…For B 2 T-TB 2 (click) synthesis, tail-to-tail fusion of two units of B 2 T(mal) peptide was accomplished by further functionalization of T epitope at the C-terminal with either an azide-or an alkyne-containing non-canonical amino acid and those end groups finally reacting via CuAAC. Additional details on the synthesis are available in refs [30,37]. The final products were purified to near homogeneity by HPLC and characterized by MS.…”

“…Our synthesis strategy involved preparation of functionalized peptide building blocks based on the B 2 T(mal) predecessor but with site-specific modifications such as an extra C-terminal functionalization of the T-cell epitope with either azide-or alkyne-containing non-canonical amino acids to enable final subunit assembly. Full details on the stepwise click chemistry-based approach, including the solving of various adverse issues encountered during process optimization due to size and structural complexity of the building blocks have been extensively reported [37].…”

Applications of Thiol-Ene Chemistry for Peptide Science

“…The use of dehydroalanine (Dha) in a peptide sequence provides an ideal target for Michael addition, and has been demonstrated as a handle for peptide modification (Zhu and van Der Donk, 2001;Bernardes et al, 2008). Furthermore, the alkene of the maleimide moiety has been utilized as a target for peptide modification in formation of the thiosuccinimide bond (Elduque et al, 2014;Forner et al, 2020). However, this review will focus exclusively on radical-mediated thiol-ene chemistry.…”