Engineering a Rugged Nanoscaffold To Enhance Plug-and-Display Vaccination

Abstract

Nanoscale organization is crucial to stimulating an immune response. Using self-assembling proteins as multimerization platforms provides a safe and immunogenic system to vaccinate against otherwise weakly immunogenic antigens. Such multimerization platforms are generally based on icosahedral viruses and have led to vaccines given to millions of people. It is unclear whether synthetic protein nanoassemblies would show similar potency. Here we take the computationally designed porous dodecahedral i301 60-mer and rationally engineer this particle, giving a mutated i301 (mi3) with improved particle uniformity and stability. To simplify the conjugation of this nanoparticle, we employ a SpyCatcher fusion of mi3, such that an antigen of interest linked to the SpyTag peptide can spontaneously couple through isopeptide bond formation (Plug-and-Display). SpyCatcher-mi3 expressed solubly to high yields in Escherichia coli, giving more than 10-fold greater yield than a comparable phage-derived icosahedral nanoparticle, SpyCatcher-AP205. SpyCatcher-mi3 nanoparticles showed high stability to temperature, freeze–thaw, lyophilization, and storage over time. We demonstrate approximately 95% efficiency coupling to different transmission-blocking and blood-stage malaria antigens. Plasmodium falciparum CyRPA was conjugated to SpyCatcher-mi3 nanoparticles and elicited a high avidity antibody response, comparable to phage-derived virus-like particles despite their higher valency and RNA cargo. The simple production, precise derivatization, and exceptional ruggedness of this nanoscaffold should facilitate broad application for nanobiotechnology and vaccine development.

Immunization with virus-like particles conjugated to CIDRα1 domain of Plasmodium falciparum erythrocyte membrane protein 1 induces inhibitory antibodies

“…Recently, methods that enable coupling of complex antigens to pre-formed VLP have been developed, employing the SpyTag/SpyCatcher conjugation system [31,33,34]. Employed in mice, these VLP vaccines have induced high and stable IgG levels against microbial antigens, including malaria antigens [48][49][50][51].…”

Covalent Functionalization of Bioengineered Polyhydroxyalkanoate Spheres Directed by Specific Protein-Protein Interactions

“…A spontaneous covalent isopeptide bond forms between a lysine residue of the SpyCatcher domain (13 kDa) and an aspartic acid of its pairing peptide SpyTag (13 amino acid residues) in a sitespecific manner, without the need of additional reagents nor enzymes at broad ligation conditions (Reddington and Howarth, 2015). The advantageous properties of the SpyTag/SpyCatcher chemistry makes it an excellent protein ligation tool for surface functionalization of various organic and inorganic materials, such as virus-like particles (Brune et al, 2016(Brune et al, , 2017Bruun et al, 2018), protein-based scaffolds (Bae et al, 2018;Choi et al, 2018;Swartz and Chen, 2018;Zhang et al, 2018a), gold nanoparticles (Ma et al, 2018), silica (Zhang et al, 2018b,c), quantum dots (Ke et al, 2018;Brizendine et al, 2019), and crystalline graphene (Tyagi et al, 2018). We recently developed a modular PHA platform using SpyTag/SpyCatcher chemistry, where we successfully showed that purified SpyTagged proteins could ligate to SpyCatcher-coated PHA spheres in vitro with decent tunability (Wong and Rehm, 2018).…”

Development of target‐tunable P22 VLP‐based delivery nanoplatforms using bacterial superglue

“…We also demonstrated that those conjugates exhibited a range of different functions (Bae et al, ; Choi et al, ; Moon et al, ). The ST/SC protein ligation system has been applied for displaying various antigenic proteins and targeting ligands on VLPs and their effective immune response inductions and cell‐specific gene delivery were successfully demonstrated (Brune et al, , ; Bruun, Andersson, Draper, & Howarth, ; Janitzek et al, ; Kasa, Raneni, Chamoun‐Emanuelli, Wright, & Chen, ; Ke et al, ; Leneghan et al, ; Singh et al, ; Thrane et al, ).…”