Human scFv Antibody Targeting CD99 for Ewing Sarcoma

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Solution Overview

Problem

Current treatments for Ewing sarcoma, particularly metastatic or recurrent cases, have limited effectiveness due to drug resistance and adverse effects from xenogenic antibodies, necessitating a more targeted and specific therapeutic approach.

Innovation Solution

Development of a human single-chain variable fragment (scFv) antibody specifically binding to the CD99 protein, produced through phage display technology, which is human-derived, minimizes immune responses, and selectively targets Ewing sarcoma cells without affecting normal tissues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional chemotherapy drugs are used to treat Ewing sarcoma, then tumour cells can be attacked, but the tumour develops multiple resistance to the drugs

Engineering Contradiction:
Improvetreatment effectivenessVSAvoiddrug resistance development
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent segments the antibody structure into a single-chain variable fragment (scFv) that contains only the antigen-binding variable regions of heavy and light chains, connected by a linker peptide. This segmentation eliminates the constant regions that are responsible for immune system recognition and resistance development, while preserving the specific binding capability to CD99 on Ewing sarcoma cells.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts and isolates only the essential functional component (variable regions VH and VL) from the complete antibody structure, discarding the constant regions that cause immune resistance. This extraction creates a minimized therapeutic agent that maintains tumour-targeting capability while avoiding the resistance problems associated with conventional chemotherapy and full-length antibodies.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If xenogenic monoclonal antibodies are used for therapy, then tumour targeting is achieved, but adverse immune responses occur

Engineering Contradiction:
Improvetumour targeting capabilityVSAvoidimmune response to xenogenic antibodies
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by humanizing the antibody fragment - the scFv is derived from human immunoglobulin variable regions, giving it human molecular characteristics at the critical antigen-binding interface. This local humanization allows the fragment to evade immune recognition while maintaining high specificity for CD99 on Ewing sarcoma cells, resolving the contradiction between tumour targeting and immune acceptance.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If conventional antibody structures are used, then high specificity is achieved, but molecular mass is large causing slower clearance

Engineering Contradiction:
Improveantigen binding specificityVSAvoidmolecular mass
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The invention extracts only the variable regions (VH and VL) that contain the antigen-binding specificity, eliminating the heavy constant regions that contribute to molecular mass. The resulting scFv has significantly reduced molecular weight while preserving the precise CD99 recognition capability, achieving faster clearance and improved pharmacokinetics without sacrificing binding specificity.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If full-length monoclonal antibodies are administered, then therapeutic effect is achieved, but toxicity and side effects increase

Engineering Contradiction:
Improvetherapeutic effectVSAvoidtoxicity and side effects
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the complete antibody into a minimal functional unit (scFv) that retains only the antigen-binding variable regions. This segmentation reduces the molecular complexity and eliminates regions that may contribute to off-target effects and toxicity, while preserving the specific therapeutic action against CD99-expressing Ewing sarcoma cells.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts and removes the constant regions and Fc portions from the full-length antibody, keeping only the essential variable regions that provide specificity. This extraction creates a safer therapeutic agent with reduced immunogenicity and lower risk of adverse reactions, while maintaining effective tumour targeting.

Inventive Principle:
Principle #2Taking out (Extraction)

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 scFv antibody effectively recognizes and binds to CD99 on Ewing sarcoma cells, offering a specific and safe therapeutic option with reduced toxicity and improved treatment outcomes, potentially combined with conventional chemotherapy or radiotherapy.

Implementation Method 1

a single-chain variable fragment (scFv) able to recognize and bind CD99 human protein

Methodology Applied
Scientific EffectAntigen-antibody binding:

Data Source

PatentEP2499163B1Single-chain variable fragment (SCFV) able to recognize and bind CD99 human protein
Publication Date: 2015.01.07 INST ORTOPEDICO RIZZOLI
  • EP2499163B1 patent drawingFigure 1A~1D
  • EP2499163B1 patent drawingFigure 2A~2B
  • EP2499163B1 patent drawingFigure 3A~3B

AI summary

The present invention relates to a single-chain variable fragment (scFv) able to recognize an epitope of the extracellular domain of CD99 human protein. The single-chain variable fragment is able to recognize and specifically and selectively bind said epitope expressed on Ewing sarcoma cells. The fragment can thus be used for the diagnosis and treatment of Ewing sarcoma.