CD34 Nanobodies for Stem Cell Targeting and Gene Delivery
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Solution Overview
Problem
Existing antibodies for targeting CD34 are large and costly, making them inefficient for certain applications, and no nanobodies specific to CD34 have been available.
Innovation Solution
Development of single domain antibodies, or nanobodies, with specific CDR sequences capable of binding to human CD34, which are smaller, more stable, and easier to produce, allowing for efficient targeting and detection of CD34-expressing cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If classical antibodies are used to target CD34, then high specificity and affinity are achieved, but the size is large and production cost is high
Solution Approach 1:
The patent extracts only the essential antigen-binding domain (variable domain) from the complete antibody molecule, discarding the Fc region and other non-essential parts. This creates a nanobody that retains CD34 binding specificity while reducing molecular weight from approximately 150 kDa to about 15 kDa, directly resolving the contradiction between binding reliability and size.
2Reliability
If classical antibodies are used to target CD34, then high specificity and affinity are achieved, but production cost is high
Solution Approach 1:
By extracting only the variable domain encoding the antigen-binding site, the patent creates a much smaller genetic sequence that is easier and cheaper to synthesize, clone, and express. The nanobody requires fewer resources for production while maintaining identical binding specificity to the parent antibody, directly addressing the cost contradiction.
Solution Approach 2:
The nanobody represents a simplified, more economical alternative to full-length antibodies. The reduced structural complexity allows for cheaper production through bacterial expression systems, making the binding function accessible at lower cost while maintaining the essential specificity requirement.
3Ease of manufacture
If nanobodies are used instead of classical antibodies, then size is reduced and production is easier, but no specific nanobodies to CD34 were available
Solution Approach 1:
The patent employs preliminary immunization of camelids with CD34 antigen to generate nanobodies with inherent binding capability before any application. This pre-selection ensures that the resulting nanobodies possess proven CD34 specificity, eliminating the risk of using unvalidated nanobody sequences and directly addressing the availability contradiction.
Solution Approach 2:
The patent changes the biological system parameter from mammalian antibodies to camelid nanobodies, which naturally produce single-domain antibodies. This parameter change enables the production of CD34-specific nanobodies with the desired small size and ease of manufacture while maintaining binding reliability through the unique properties of camelid immune system-derived antibodies.
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 nanobodies exhibit high specificity and affinity to human CD34, enabling effective detection and targeting of CD34-expressing cells, facilitating applications such as gene transfer and imaging with improved tissue penetration and reduced immunogenicity.
Implementation Method 1
single domain antibodies or nanobodies which due to their small size can be more easily produced and which can better infiltrate tissues are known in the art
Data Source
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AI summary
The present invention relates to single domain antibodies - also designated nanobodies - to CD34 as well as nucleic acids encoding them and pharmaceutical compositions comprising them. Specific nanobodies capable of binding to human CD34 on cells, e.g., on hematopoietic stem cells, are provided. These are useful for targeting agents, e.g., gene transfer moieties such as lipid nanoparticles (LNP), to the cells in vitro or in vivo, for example in the context of genetic engineering of CD34+ cells. The nanobodies are also useful for diagnostic or for imaging applications.