Defined asymmetric circular Tandem Repeat Protein (cTRP) scaffold for precise multivalent protein presentation

Engineered nanoparticle scaffold to present multiple distinct proteins in defined positions around a toroidal ring, boosting cross-reactive antibody discovery, multi-valent subunit vaccine design, and multi-enzyme substrate channeling.

Background

Protein nanoparticle scaffolds are powerful tools for enhancing immunogenicity and vaccine efficacy through the multivalent presentation of antigens. Compared to larger virus-like particle (VLP) platforms, the self-assembling circular tandem repeat protein (cTRP) scaffold offers a compact and precisely tunable architecture. Its valency can be systematically controlled by altering the number of repeated protomer units, enabling fine control over antigen density and spatial orientation. The cTRP platform has been functionally validated for the display of T cell agonists (PMID: 32203491), advanced as a strong Epstein–Barr virus (EBV) vaccine candidate (PMID: 35705092), and shown to be compatible with mRNA-based delivery (PMID: 38926438). Building on this foundation, we have further advanced the cTRP technology by redesigning protomer–protomer interfaces to achieve positional definition around the toroidal ring, thereby enabling site-specific incorporation and modular assembly of functional elements.

Technology

This technology is a modular protein nanoparticle scaffold that enables precise, stoichiometrically defined co-display of multiple distinct proteins within a single toroidal assembly. Protomers built from tandem α-helical repeat units self-assemble and are then covalently locked into defined hetero-oligomeric rings by strategically positioned inter-protomer disulfide bonds, enforcing fixed 1:1:1:1 composition and positional specificity. Antigens, ligands, or enzymes can be genetically fused to protomer termini to achieve multivalent, spatially ordered presentation for multi-species protein immunogens, candidate vaccine designs, T cell activation reagents, enzymatic substrate channeling, or multispecific targeting.

The technology has been utilized in multiple antibody discovery campaigns in human transgenic rodents, where the designs have driven strong cross-reactive immune responses resulting in the successful isolation of hundreds of cross-reactive mAbs against clinically relevant targets, demonstrating the utility of this platform for eliciting challenging specificities and generating candidates suitable for therapeutic advancement.

Benefits

  • Precisely controlled multivalent display of distinct proteins in defined stoichiometries
  • Enhanced cross-reactive immunogenicity
  • Versatile platform for multivalent vaccine development and cross-protective antibody generation
  • Facilitates defined substrate channeling in multi-enzyme biosynthetic pathways

Applications

  • Multi-species cross-reactive antibody discovery
  • Multi-valent subunit vaccine development
  • Multi-specific cell targeting
  • Multi-enzyme substrate channeling