Anti-4-1BB Nanobodies for Ligand Blocking and Fc Crosslinking
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Solution Overview
Problem
Existing cancer therapies lack effective and targeted activation of 4-1BB signaling for enhanced immune response against tumors, and existing antibodies either activate signaling independently or fail to effectively block the 4-1BB ligand interaction.
Innovation Solution
Development of anti-4-1BB nanobodies with specific CDR sequences that bind to human 4-1BB, blocking its ligand interaction and requiring Fc crosslinking for activation, suitable for inclusion in bispecific or trispecific antibodies to activate 4-1BB signaling in the presence of a target antigen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing antibodies are used to activate 4-1BB signaling, then immune response is enhanced, but the antibodies either activate signaling independently or fail to effectively block the 4-1BB ligand interaction
Solution Approach 1:
The patent divides the antibody function into separate components: one nanobody (e.g., VV02-1LP-263) specifically blocks the 4-1BB ligand interaction, while another nanobody (e.g., VV02-1SP(1)-73) provides Fc crosslinking for activation. This segmentation allows independent optimization of blocking and activation functions, resolving the contradiction between reliable blocking and controlled activation.
Solution Approach 2:
The patent introduces Fc crosslinking as an intermediary mechanism that mediates between the blocking nanobody and the activation requirement. The Fc region serves as a mediator that, when crosslinked, transmits the activation signal to the blocked 4-1BB receptor, enabling controlled activation only when both blocking and crosslinking conditions are met.
2Reliability
If full-length antibodies are used, then binding affinity is achieved, but molecular weight is large (150-160 kDa) limiting suitability for certain protein fragments
Solution Approach 1:
The patent extracts only the essential functional elements from full-length antibodies - specifically the variable domains (VHH fragments) that provide binding affinity - and discards the unnecessary constant regions and heavy chains. This extraction results in nanobodies with molecular weight of only 12-15 kDa that maintain binding affinity while being suitable for inclusion in protein fragments and other applications.
3Ease of operation
If nanobodies are designed for Fc crosslinking activation, then targeted activation is achieved, but the mechanism becomes more complex requiring crosslinking conditions
Solution Approach 1:
The patent designs the nanobody system to serve multiple functions: the same Fc region that provides structural stability also enables crosslinking activation, and the nanobody can function as both a blocking agent and an activation trigger under different conditions. This multi-functionality reduces the need for separate activation mechanisms, simplifying the overall system despite the added crosslinking requirement.
Data Source
AI summary
Provided are anti-4-1BB nanobodies and bispecific or multispecific antibodies that incorporate the nanobodies. Methods of using the antibodies for treating and diagnosing diseases such as cancer are also provided.