Modified Polypeptide Trimerization for CRP Binding
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Solution Overview
Problem
The therapeutic potential of monoclonal antibodies in treating diseases, particularly cancer, is limited by the ability of diseased cells to express membrane complement regulatory proteins (CRPs) like CD35, CD46, and CD59, which inhibit complement-dependent cytolysis (CDC) by blocking the complement cascade and preventing the assembly of the membrane attack complex (MAC).
Innovation Solution
A modified polypeptide with at least 90% sequence identity to the Ad35 fiber knob sequence, including specific amino acid substitutions, is used to trimerize and reduce the activity, amount, or density of CRPs on target cell surfaces, enhancing the susceptibility of cells to CDC by binding with high affinity to CRPs such as CD46, thereby sensitizing tumor cells to antibody-mediated therapies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If monoclonal antibodies are used to activate complement cascade for treating cancer, then tumor cell killing is improved, but the ability of diseased cells to block killing through CRP expression worsens the therapeutic potential
Solution Approach 1:
The patent uses a soluble CRP-binding protein as an intermediary substance that binds to CRPs on tumor cell surfaces, preventing CRPs from blocking complement activation. This intermediary protein blocks the harmful interaction between CRPs and complement components, thereby enabling effective tumor cell killing by monoclonal antibodies while overcoming the inhibitory effect of CRP expression.
Solution Approach 2:
The patent extracts or removes CRPs from the tumor cell surface by using soluble binding proteins that sequester these regulatory proteins. This extraction approach eliminates the harmful CRP activity on cell surfaces, allowing complement-dependent cytotoxicity to proceed effectively against tumor cells without being inhibited by CRP-mediated blocking.
2Reliability
If CRPs are expressed on target cell surfaces to block complement cascade, then cell survival is improved, but susceptibility to CDC is worsened
Solution Approach 1:
The soluble CRP-binding protein acts as an intermediary that interferes with the protective function of CRPs. By binding to CRPs on cell surfaces, the intermediary protein prevents CRPs from regulating complement activation, thereby reducing cell survival mechanisms and increasing susceptibility to complement-dependent cytotoxicity.
Solution Approach 2:
The patent applies preliminary anti-action by introducing soluble binding proteins that preemptively neutralize CRPs before complement activation can occur. This preliminary blocking of CRP function prevents the protective effect of these proteins, thereby enhancing the effectiveness of complement-mediated cell killing.
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 modified polypeptide effectively reduces the surface levels of CRPs, increasing the susceptibility of tumor cells to CDC and enhancing the efficacy of antibody therapies, as demonstrated by increased cell killing in both in vitro and in vivo models, leading to improved treatment outcomes for cancer and other conditions.
Implementation Method 1
A modified polypeptide with at least 90% sequence identity to the Ad35 fiber knob sequence, including specific amino acid substitutions, is used to trimerize and reduce the activity, amount, or density of CRPs on target cell surfaces
Implementation Method 2
binding with high affinity to CRPs such as CD46, thereby sensitizing tumor cells to antibody-mediated therapies
Data Source
Figure 1A
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Figure 1C
AI summary
This invention relates to agents capable of reducing the activity, amount or density of complement regulatory proteins (CRPs) on target cells. The invention also provides methods of identification of such agents, methods of making, and uses thereof.