Circularly Permuted LTB Protein Adjuvant With Lower Cytotoxicity

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Solution Overview

Problem

Traditional vaccine adjuvants face issues of insufficient stability and cytotoxicity, limiting their effectiveness in inducing robust immune responses against respiratory pathogens.

Innovation Solution

The development of recombinant proteins with circularly permuted B5 subunits of type II heat labile enterotoxin (LTB) variants, specifically designed to reduce GD1a binding affinity while maintaining TLR 2/1 activation, through structural modifications using a GSGS linker to disconnect critical residues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional vaccine adjuvants are used to enhance immune response, then immune stimulation is improved, but cytotoxicity increases and stability decreases

Engineering Contradiction:

Improveimmune response effectivenessVSAvoidcytotoxicity

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The LTB protein is divided into functional domains through circular permutation, separating the TLR2/1 activation function from the GD1a binding function. This segmentation allows selective modification of the GD1a binding region while preserving the immunostimulatory TLR activation capability, thereby reducing cytotoxicity while maintaining immune response effectiveness

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent modifies the molecular structure of LTB by introducing circular permutation at specific sites (disconnecting loops and reconnecting termini), which changes the spatial arrangement and binding parameters of the protein. This structural parameter change reduces GD1a binding affinity and associated cytotoxicity while maintaining TLR2/1 activation capability

Inventive Principle:

Principle #35Parameter changes

2Reliability

If traditional vaccine adjuvants are used to stimulate immune response, then immune activation is improved, but structural stability deteriorates

Engineering Contradiction:

Improveimmune activationVSAvoidprotein structural stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent performs preliminary structural optimization of the LTB protein through circular permutation before vaccine formulation. By pre-modifying the protein structure to enhance stability while maintaining immunostimulatory function, the adjuvant achieves both structural stability and effective immune activation without requiring post-formulation adjustments

Inventive Principle:

Principle #10Preliminary action

3Reliability

If LTB protein is used as adjuvant to enhance immune response, then antibody response is improved, but GD1a binding affinity increases causing cytotoxicity

Engineering Contradiction:

Improveantibody responseVSAvoidGD1a binding-mediated cytotoxicity

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts or removes the GD1a binding function from the LTB protein through circular permutation that disconnects the loops involved in GD1a interaction. This extraction eliminates the harmful cytotoxic effect while preserving the beneficial TLR2/1 activation and antibody response enhancement functions

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the potentially harmful GD1a binding activity into a beneficial or neutral property by modifying the protein structure through circular permutation. The modified LTB variant maintains immunostimulatory benefits while the reduced GD1a binding transforms the harmful cytotoxic effect into a safer profile suitable for vaccine adjuvant application

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS20260055147A1Recombinant protein and preparation process thereof, protein adjuvant for vaccine comprising recombinant protein, and use of recombinant protein for preventing respiratory disease

Publication Date: 2026.02.26 NATIONAL TSING HUA UNIVERSITY

AI summary

The present disclosure provides a recombinant protein and the preparation process thereof, a protein adjuvant for vaccines including the recombinant protein, and a use of the recombinant protein for preventing respiratory diseases. The recombinant protein of the present disclosure achieves the effect of preventing respiratory diseases through various efficacy experiments.