Engineered PD-L1 Variants with Enhanced PD-1 Affinity for Sepsis Treatment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current treatments for sepsis, particularly focusing on modulating PD-1 signaling, fail to effectively prevent organ failure due to autoimmune activation of cytotoxic T-cells during massive infections, leading to organ damage and death.
Innovation Solution
A PD-L1 polypeptide with specific amino acid substitutions at positions V54, Y56, Q63, Q66, V68, A69, P76, I115, A121, D122, Y123, K124, and R125, designed to enhance affinity for PD-1, thereby preventing autoimmune activation of cytotoxic T-cells and reducing inflammatory responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Fc-fusion proteins of extracellular PD-L1 are used for treatment, then organ failure during sepsis may be prevented, but the affinity for PD-1 is insufficient requiring high concentrations
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of PD-L1 to alter its binding affinity parameters. Specifically, mutations at positions 54, 56, 63, 66, 68, 69, and 76 change the physical-chemical properties of the binding interface, enabling stronger interaction with PD-1 at lower concentrations, thus resolving the contradiction between therapeutic efficacy and required substance quantity
2Reliability
If neutralizing antibodies against TNFα are used to block hyper-inflammation, then immune stimulation is limited and patients survive the hyper-inflammatory phase, but the hypo-inflammatory phase is enhanced causing multi-organ-dysfunction syndrome and death
Solution Approach 1:
The patent applies local quality by creating PD-L1 variants with enhanced binding affinity specifically at the PD-1 interaction interface while maintaining the natural distribution and function of endogenous PD-L1 in other tissues. This localized enhancement allows precise modulation of T-cell activation without causing systemic immunosuppression, thereby preventing both hyper-inflammation and the harmful hypo-inflammatory phase
3Reliability
If PD-L1 with wildtype affinity is used, then binding to PD-1 occurs but high concentrations are needed to achieve therapeutic effect, increasing the risk of off-target effects
Solution Approach 1:
The patent changes the binding affinity parameter of PD-L1 through site-directed mutagenesis at the PD-1 interaction interface. The mutated PD-L1 variants exhibit increased affinity (lower Kd values) for PD-1, allowing therapeutic effects to be achieved at lower concentrations, thereby maintaining binding specificity while reducing the risk of off-target effects associated with high-dose administration
Data Source
AI summary
The present invention relates to a PD-L1 polypeptide comprising at least a first amino acid sequence at least 70% identical to SEQ ID NO:8, and at least a second sequence at least 70% identical to SEQ ID NO: 10, wherein the polypeptide carries amino acid substitutions at least at the amino acid positions Y56 and P76, wherein the amino acid positions are based on the murine PD-L1 amino acid sequence (SEQ ID NO:6). The present invention also relates to a polynucleotide encoding the aforesaid PD-L1 polypeptide, and to host cells, methods, and uses related thereto.