Synthetic Long Peptide Linkers for CD4/CD8 Cancer Vaccines
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Solution Overview
Problem
Existing cancer vaccines face limitations in inducing long-term survival due to anergic CD8 T cells from lack of CD4 T cell help, and there is a need for an optimal linker design in synthetic long peptides (SLPs) to enhance T cell activation.
Innovation Solution
Designing SLPs with a specific linker sequence (Xaa1-LSV-Xaa5-Xaa6) that allows efficient processing by antigen-presenting cells, linking CD4 class II and CD8 class I peptides, avoiding neo-antigen formation, and promoting effective T cell activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If minimal CTL epitopes (9-10 amino acids) are used as immunogens, then the vaccine structure is simple and easy to manufacture, but the induction of effector T cells is limited and clinical efficacy is disappointing
Solution Approach 1:
The patent combines multiple epitopes (CD8+ CTL epitopes and CD4+ T helper epitopes) into a single synthetic long peptide construct. This merging allows the vaccine to simultaneously stimulate both cytotoxic T cells and helper T cells, resolving the contradiction by creating a more effective immunogen that overcomes the limitations of minimal epitopes while maintaining manufacturing simplicity.
Solution Approach 2:
The synthetic long peptide is designed as a composite structure containing multiple functional domains: CD8+ epitopes for cytotoxic T cell activation, CD4+ epitopes for helper T cell activation, and linker regions for proper presentation. This composite design enables the vaccine to elicit comprehensive immune responses, improving clinical efficacy without compromising ease of manufacture.
2Adaptability or versatility
If full length recombinant proteins are used as immunogens, then a wide range of epitopes are covered, but intracellular processing efficiency is reduced compared to synthetic long peptides
Solution Approach 1:
The patent segments the full-length antigen into specific epitopic regions and reconstructs them as synthetic long peptides with optimized sequences and linkers. This segmentation allows selective inclusion of immunologically relevant epitopes while removing non-essential regions, thereby improving intracellular processing efficiency and antigen presentation while maintaining broad epitope coverage.
Solution Approach 2:
The patent optimizes parameters of the immunogen including peptide length, amino acid sequence, and linker composition to enhance processing by antigen-presenting cells. By changing these parameters from the native full-length protein structure to a tailored synthetic long peptide format, the vaccine achieves superior intracellular processing efficiency while preserving comprehensive epitope representation.
3Device complexity
If synthetic long peptides are designed without optimized linkers, then the design process is simpler, but T cell activation efficiency is reduced
Solution Approach 1:
The patent introduces specifically designed linker sequences as intermediary elements between CD8+ and CD4+ epitopes. These linkers serve as mediators that facilitate proper folding, stability, and presentation of the composite epitopes to T cells. The linkers contain specific amino acid motifs that enhance processing by proteases in antigen-presenting cells, thereby improving T cell activation efficiency without significantly increasing design complexity.
Data Source
AI summary
The present invention relates to the prevention and treatment of disease like cancer. The inventors have previously characterized MELOE-1 antigen as an IRES dependent, melanoma specific translation product from a lncRNA mainly transcribed in the melanocytic lineage. MELOE-1 contains numerous class II epitopes and one HLA-A*0201-restricted CD8 epitope eliciting a frequent repertoire of high avidity T cells. They designed various synthetic long peptide (SLPs) comprising a CD4 epitope coupled to the CD8 epitope by a serie of linkers of 4 to 6 aa and studied the efficacy of T cell clone activation by SLP-loaded DC in vitro. Particularly, they evaluated the ability of a few selected SLPs to stimulate specific T cells proliferation of PBL from healthy donors in vitro and finally, they explored the vaccination potential of their best SLP candidate in vivo in an HLA*A0201/HLA-DRB0101 transgenic mouse. Thus, the present invention relates a SLP comprising a CD4 class II peptide linked to a CD8 class I peptide by a specific linker and its use in the treatment of disease like cancers.