Self-Assembled Protein Nanoparticle for Stable Antigen Presentation
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Solution Overview
Problem
The development of self-assembled protein nanoparticles (SAPNs) based on the hepatitis B virus core antigen faces challenges such as reduced effectiveness in individuals already exposed to the virus and disruption of self-assembly properties due to foreign epitope insertion, and there is a need for a hydrophobic patch-free SAPN that can stimulate long-duration antibody responses.
Innovation Solution
A recombinant protein composed of an amphipathic helical peptide from the M2 protein of type A influenza virus and a superfolder green fluorescent protein (sfGFP) with a target peptide insertion site between beta sheet 8 and 9, which forms hydrophobic patch-free SAPNs capable of spontaneous assembly and high thermal stability, allowing for efficient antigen presentation and immune response stimulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HBcAg is used as the basis for SAPN, then self-assembly capability is achieved, but effectiveness is reduced in individuals already exposed to the virus
Solution Approach 1:
The HBcAg protein is divided into functional segments: the self-assembly domain (residues 1-149) is separated from the C-terminal domain. Foreign epitopes are inserted into the assembly domain rather than replacing the entire protein, allowing self-assembly capability to be preserved while introducing new antigenic targets for exposed individuals.
Solution Approach 2:
The patent combines the self-assembly capability of HBcAg with foreign epitopes from other pathogens. This merging creates a chimeric SAPN that maintains the structural integrity and self-assembly properties of HBcAg while incorporating new antigenic determinants that can elicit immune responses in individuals already exposed to HBV.
2Adaptability or versatility
If foreign epitopes are inserted into HBcAg to expand antigenicity, then adaptability improves, but self-assembly property is disrupted
Solution Approach 1:
Foreign epitopes are inserted at specific local regions within the HBcAg assembly domain where they are least likely to interfere with the overall self-assembly mechanism. The insertion sites are carefully selected to maintain the alpha-helical structure and interdimer contact interfaces that are critical for SAPN formation.
Solution Approach 2:
The self-assembly domain of HBcAg is engineered in advance with predetermined insertion sites for foreign epitopes. This preliminary design ensures that the protein maintains its ability to self-assemble while incorporating multiple foreign antigens, allowing subsequent expression and assembly to proceed without disruption.
3Quantity of substance
If conventional SAPNs are used, then antigen presentation is achieved, but hydrophobic patches cause aggregation and reduced stability
Solution Approach 1:
The patent identifies hydrophobic patches on conventional SAPNs as problematic for stability and aggregation resistance. By engineering the HBcAg-based SAPN to eliminate these hydrophobic patches through rational design and epitope insertion strategies, the invention converts a harmful feature into a beneficial one, achieving both stable nanoparticle formation and effective antigen presentation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The recombinant protein nanoparticles induce long-lasting antibody responses and high affinity antibodies, maintaining stability and activity even at elevated temperatures, and do not interact with bacterial membranes, making them suitable for vaccine applications.
Implementation Method 1
spontaneous assembly
Implementation Method 2
hydrophobic patch free
Implementation Method 3
high thermal stability
Data Source
AI summary
Self-assembled protein nanoparticle (SAPN) are excellent antigen due to its ability to simultaneously present multiple epitopes to B cell and generate much stronger B cell receptor signaling than single epitope. Most of the SAPN are derived from capsid protein of virus or bacterial phage, which suffer from low particle stability, existing antibody against capsid protein and structural intolerant to peptide insertion. In this invention, we have created a SAPN using non-viral protein that is both thermal stable and tolerate to target peptide insertions. The assembling subunit of this SAPN is a fusion protein between two components: first, a polymerization module composed of an amphipathic helical peptide modified from M2 protein of type A influenza virus and second, a target peptide presentation module that composed of a superfolder green fluorescent protein (sfGFP) with a peptide insertion site on a specific loop of sfGFP. This particle is able to incorporate target peptide through genetic recombination and presented the target protein in the surface of nanoparticle to stimulate the production of high affinity antibody against target peptide without using adjuvant.