Engineered Single-Domain CD4 Antibody Domains for HIV-1 gp120 Binding

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Solution Overview

Problem

Current anti-HIV therapies lack effectiveness and new molecular targets are needed to inhibit HIV-1 entry into host cells.

Innovation Solution

Engineered antibody domains (eAds) and single-domain CD4 polypeptides, along with fusion proteins combining these with various partners, are developed to target HIV-1 gp120, enhancing stability and potency through specific amino acid sequences and linkers, thereby inhibiting HIV infection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If recombinant solubly expressed CD4 (sCD4) containing all four extracellular domains is used to inhibit HIV-1 entry, then the binding affinity to gp120 is improved, but the molecular size and structural complexity increase

Engineering Contradiction:

Improvebinding affinityVSAvoidmolecular complexity

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The patent divides the four-domain CD4 structure into separate single-domain units (D1, D2, D3, D4) that can function independently or in combination. This segmentation allows the use of smaller, simpler domain configurations (e.g., D1D2 or D1 alone) that retain sufficient binding affinity while reducing molecular complexity compared to the full four-domain construct.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extracts and utilizes only the essential domains (D1 or D1D2) required for gp120 binding, discarding the non-essential D3 and D4 domains. This extraction maintains the core functional capability of HIV entry inhibition while significantly reducing the molecular size and complexity of the therapeutic agent.

Inventive Principle:

Principle #2Taking out (Extraction)

2Manufacturing precision

If engineered antibody domains with specific amino acid sequences are developed to target HIV-1 gp120, then the binding specificity is improved, but the development complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvebinding specificityVSAvoidmanufacturing ease

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent employs systematic amino acid sequence optimization within defined variable regions (VL and VH) of the antibody domains. By focusing mutations and engineering efforts on specific parameter regions (the complementarity determining regions) rather than the entire protein structure, the patent achieves high binding specificity while maintaining relatively simple manufacturing processes.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The engineered antibody domains are designed with framework regions that can be standardized and reused across different specificities. The patent creates a modular system where the variable regions provide target-specific binding while the constant framework regions provide structural stability and can be manufactured using standardized protocols, thereby improving ease of manufacture.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If fusion proteins combining engineered antibody domains with fusion partners are created, then the stability and tissue penetration are improved, but the protein structure complexity increases

Engineering Contradiction:

Improveprotein stabilityVSAvoidprotein structure

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent merges the engineered antibody domains with stable fusion partner proteins (such as albumin or Fc regions) to create fusion proteins that inherit the stability and long circulation half-life of the partners. This merging approach improves protein stability and pharmacokinetic properties while maintaining a relatively simple overall structure that can be produced using standard recombinant expression systems.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses flexible linker peptides as intermediaries to connect the antibody domain to the fusion partner. These linkers serve as flexible connectors that allow both domains to maintain their functional conformations while being part of a larger fusion protein, thereby improving stability without requiring complex structural integration.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

These engineered domains and fusion proteins demonstrate improved binding affinity and specificity, leading to potent neutralization of HIV-1 across multiple clades, with enhanced stability and tissue penetration, offering a promising new approach to inhibit HIV infection.

Implementation Method 1

Methodology Applied

Scientific EffectAntibody-antigen binding:

Data Source

PatentEP3957651A1High-affinity fully functional soluble single-domain human CD4, antibodies, and related fusion proteins

Publication Date: 2022.02.23 THE GOVERNMENT OF THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY DEPARTMENT OF HEALTH & HUMAN SERVICES

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AI summary

The invention provides engineered antibody domains (eAds), a polypeptide comprising a single-domain CD4, as well as a fusion protein comprising the same. Nucleic acids encoding eAd and/or polypeptide or the fusion protein thereof, as well as compositions or cells comprising the eAd, polypeptide, fusion protein, or nucleic acid also are provided.