Stabilized Procalcitonin Antigen for High-Affinity Antibody Production

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Solution Overview

Problem

The instability of the N-terminal fragment of procalcitonin antigen leads to a weak immune response when used for immunization, making it challenging to produce efficient antibodies for diagnosing bacterial and fungal infections.

Innovation Solution

Mutation of individual amino acids within the N-terminal fragment of procalcitonin, specifically between positions 19 to 40, to enhance stability and produce a recombinant protein that, when co-emulsified with an adjuvant, results in a more efficient antibody production, with the epitope identified as amino acids from positions 20 to 35.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pure human procalcitonin antigen is used for immunization, then the antibody can specifically bind to procalcitonin, but the unstable N-terminal fragment generates weak immune response

Engineering Contradiction:
Improvespecificity of antibody bindingVSAvoidimmune response strength
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies parameter changes by mutating specific amino acid residues in the N-terminal fragment of procalcitonin (positions 19-40) to improve the stability and immunogenicity of the antigen. This chemical/structural modification allows the antigen to maintain its specific binding capability while generating a stronger immune response, resolving the contradiction between specificity and productivity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a recombinant protein that copies the essential features of native procalcitonin while incorporating stabilized mutations. This synthetic copy retains the epitope structure needed for specific antibody binding but improves stability to enhance immune response, effectively resolving the contradiction between reliability and productivity.

Inventive Principle:
Principle #26Copying

2Reliability

If the N-terminal fragment of procalcitonin is used as antigen, then the antibody can recognize procalcitonin, but the fragment is easily degraded leading to weak immune response

Engineering Contradiction:
Improveantibody recognition capabilityVSAvoidstability of procalcitonin fragment
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent modifies the chemical structure of the N-terminal fragment by introducing mutations at specific positions (19-40) that enhance structural stability. This parameter change prevents degradation while maintaining the epitope structure needed for antibody recognition, simultaneously improving both reliability and stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary anti-action by pre-stabilizing the protein structure through mutation before immunization. This preventive measure counteracts the degradation that would otherwise occur during storage and handling, ensuring the antigen maintains its recognition capability throughout the immunization process.

Inventive Principle:
Principle #9Preliminary anti-action

3Stability of the object's composition

If mutations are introduced in amino acid positions 19-40 to improve stability, then the antigen stability increases, but the epitope structure must be preserved

Engineering Contradiction:
Improvestability of recombinant proteinVSAvoidepitope binding specificity
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies local quality by making targeted mutations only in specific regions (positions 19-40) that affect stability, while leaving the epitope region (positions 20-35) intact or minimally affected. This localized modification approach allows the protein to gain stability without compromising the epitope structure needed for specific antibody binding.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the procalcitonin sequence into functional regions: the stability-critical N-terminal fragment (positions 19-40) and the epitope region (positions 20-35). By treating these segments differently through targeted mutation, the patent independently optimizes stability and binding specificity without compromising either function.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3702370B1Monoclonal antibody of human procalcitonin, and application thereof
Publication Date: 2025.03.26 NANJING NORMAN BIOLOGICAL TECH
  • EP3702370B1 patent drawingFigure 1~2
  • EP3702370B1 patent drawingFigure 3~4
  • EP3702370B1 patent drawingFigure 5

AI summary

The present invention provides a monoclonal antibody that specifically binds to human-derived procalcitonin and application thereof. The present invention also provides a hybridoma cell line secreting the monoclonal antibody and having an accession number of CGMCC No. 10417.