PD-1 Variant Engineering for High-Affinity PD-L1 Binding
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Solution Overview
Problem
Existing PD-1 proteins have low affinity for PD-L1, making it difficult for antibody therapeutic agents to effectively inhibit PD-1/PD-L1 binding in the tumor micro-environment, and there is a need for smaller proteins that can penetrate cancer tissue more easily.
Innovation Solution
Development of PD-1 variants with specific amino acid substitutions, such as F13I, M46I, C69T, and G100V, to increase binding affinity to PD-L1, along with aglycosylated variants to enhance stability and ease of production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional monoclonal antibodies are used to block PD-1/PD-L1 binding, then immune checkpoint inhibition is achieved, but the molecules are too large to penetrate cancer tissue effectively
Solution Approach 1:
The patent segments the large monoclonal antibody into a smaller single-domain antibody fragment (sdAb) that retains the ability to bind PD-1 or PD-L1. This segmentation reduces molecular size from the full antibody scale to a compact domain scale, enabling tissue penetration while preserving immune checkpoint inhibition function.
Solution Approach 2:
The patent extracts the essential binding domain from the complete monoclonal antibody structure. By isolating and optimizing the single domain responsible for PD-1/PD-L1 binding, the invention creates a minimized molecule that maintains therapeutic efficacy without the bulk of the full antibody.
2Weight of moving object
If PD-1 protein is used to inhibit PD-L1 binding, then the molecule is small enough to penetrate tissue, but the binding affinity to PD-L1 is insufficient
Solution Approach 1:
The patent applies parameter changes by systematically mutating amino acid residues in the PD-1 single-domain antibody. Through rational design and directed evolution, specific residues are modified to enhance binding affinity to PD-L1, transforming the weak binder into a high-affinity inhibitor while maintaining the small molecular size.
Solution Approach 2:
The patent employs feedback mechanisms through iterative rounds of binding assays and structural analysis. Binding data from initial PD-1 variants informs subsequent mutation decisions, creating a feedback loop that progressively optimizes affinity for PD-L1 while preserving the compact molecular structure.
Data Source
AI summary
The present disclosure relates to PD-1 variants having minimal mutations for enhancing binding ability to PD-L1. The PD-1 variants of the present disclosure have fewer mutations than existing PD-1 and PD-1 variants and have significantly increased binding ability to PD-L1 compared to the existing variants, thereby solving the problem of immunogenicity. In addition, since these variants are very small-sized proteins as compared to existing antibody therapeutic agents, PD-1/PD-L1 binding of tumors and immune cells in a tumor micro-environment can be effectively inhibited, and since the problem of low binding ability of PD-L1 to existing PD-1 has been solved, the therapeutic effect thereof as a therapeutic agent can be significantly improved. These variants can also be used as an imaging agent for detecting the expression level of PD-L1.