Stem Cell-Derived Dendritic Cells for Epitope Identification
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Solution Overview
Problem
Current methods for predicting epitope sequences that induce immunogenicity are limited by the variability of MHC molecule allotypes and the difficulty in isolating stable antigen-presenting cells, leading to inconsistent results and challenges in determining which peptides are responsible for immunogenicity in patients.
Innovation Solution
An in vitro method for producing dendritic cells from stem cells or progenitor cells, which express specific MHC molecules, allowing for the stable production of antigen-presenting cells with diverse MHC allotypes, enabling more accurate prediction of immunogenicity and identification of epitope sequences using serum-free differentiation and MHC-associated peptide proteomics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If primary cells (PBMCs) are used to produce dendritic cells, then antigen presentation can be performed, but the variability of MHC molecule allotypes and difficulty in isolating stable antigen-presenting cells lead to inconsistent results
Solution Approach 1:
The patent uses stem cells as a reproducible source to generate dendritic cells with specific MHC allotypes. Instead of relying on variable primary cells, the invention creates standardized cell lines that can be copied and expanded, ensuring consistent antigen presentation results while maintaining the ability to study diverse MHC allotypes through controlled differentiation of stem cells with known genetic backgrounds.
2Productivity
If serum-containing medium is used for differentiation, then cell growth is supported, but serum-derived peptides contaminate the system and interfere with epitope identification
Solution Approach 1:
The patent removes serum from the differentiation medium, extracting the contaminating factor while maintaining essential growth support through defined serum-free components. This elimination of serum prevents peptide contamination from serum proteins, ensuring that identified epitopes genuinely originate from the target antigen rather than medium contaminants.
Solution Approach 2:
The invention changes the chemical composition parameters of the culture medium from serum-containing to serum-free, using precisely defined components that support cell differentiation without introducing contaminating peptides. This parameter change maintains productivity while dramatically improving the precision of epitope identification by eliminating a major source of background noise.
3Measurement precision
If MHC-associated peptide proteomics is performed without standardized antigen-presenting cells, then peptide sequences can be identified, but the variability in MHC allotypes makes it difficult to determine causative epitopes
Solution Approach 1:
The patent segments the study of MHC allotypes into distinct, controlled groups by using stem cells with known genetic backgrounds. This segmentation allows systematic comparison of specific MHC allotypes (e.g., HLA-DR, HLA-DQ, HLA-DP) and their associated peptides, making it possible to identify causative epitopes by controlling which MHC allotypes are present in each experimental group.
Data Source
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AI summary
In one aspect, the present invention provides, for example, an improved method for identifying an epitope on a protein, comprising the following steps: (A) contacting a major histocompatibility complex (MHC molecule)-expressing cell differentiated from a stem cell or a progenitor cell derived therefrom with a target protein; (B) isolating a complex of a peptide contained in the target protein and the MHC molecule from the MHC molecule-expressing cell; and (C) eluting the peptide from the complex and identifying the peptide.