Nucleic Acid Constructs for CD4 and CD8 Epitope Presentation
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Solution Overview
Problem
Current antigen-specific therapies for autoimmune disorders face challenges in eliciting a broad tolerogenic response and effectively targeting pathogenic T cells, as they often rely on symptomatic approaches that increase susceptibility to infections and have limited success in modulating immune responses to multiple disease-driving T cells.
Innovation Solution
The development of nucleic acid constructs that differentially target CD4 and CD8 epitopes to appropriate intracellular processing machinery via MHC class I or II pathways, with the option to co-express inhibitory ligands or cytokines to induce tolerance, and the use of polycationic molecules for enhanced uptake and processing in non-professional antigen-presenting cells like stromal cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antigen-specific therapy targets multiple disease-driving T cells, then immune tolerance is improved, but device complexity increases due to need for multiple epitope pathways
Solution Approach 1:
The nucleic acid construct is segmented into distinct functional domains: an N-terminal MHC class II targeting sequence for CD4+ T cell epitope presentation, a central protease cleavage site for processing, and a C-terminal MHC class I targeting sequence for CD8+ T cell epitope presentation. This segmentation allows independent optimization of each pathway while maintaining overall construct functionality, resolving the contradiction between targeting multiple T cell types and managing construct complexity.
Solution Approach 2:
The single nucleic acid construct serves multiple functions simultaneously: it encodes epitopes for both MHC class I and MHC class II pathways, includes self-processing protease cleavage sites, and provides targeting sequences for both CD4+ and CD8+ T cell activation. This multi-functionality eliminates the need for separate constructs for each T cell pathway, reducing overall system complexity while achieving broad immune tolerance.
2Measurement precision
If epitopes are differentially targeted to MHC class I and II pathways, then presentation precision is improved, but manufacturing precision requirements increase
Solution Approach 1:
The construct incorporates pre-designed protease cleavage sites at specific positions between the MHC class II and MHC class I epitope regions. These cleavage sites are engineered to be recognized by ubiquitous proteases present in antigen-presenting cells, ensuring automatic and precise separation of epitopes during natural cellular processing. This preliminary design of processing sites eliminates the need for complex external manipulation to achieve precise epitope differentiation.
Solution Approach 2:
The nucleic acid construct contains self-processing elements in the form of protease cleavage sites that are automatically recognized and processed by endogenous proteases within antigen-presenting cells. This self-service mechanism ensures precise epitope separation and routing to appropriate MHC pathways without requiring external intervention or complex manufacturing controls, thereby achieving high presentation precision with manageable manufacturing requirements.
Data Source
AI summary
The invention relates to constructs, cells and methods for modulating the immune system that optimize presentation of CD4 and CD8 epitopes to antigen-presenting cells and transfection into cells. Epitopes to either self antigens or non-self antigens can be used to optimize either a tolerance or immunogenicity to those epitopes, respectively. Certain new constructs encode one or more dominant, disease-driving epitopes (CD4) targeted for MHCII processing within the endosomes of a cell and one or more epitopes (CD8) targeted for MHCI processing within the cytosol of the cell, to produce the maximum antigen/epitope presentation in the immune system, and further include an MHCII activator sequence. Alternatively, the new constructs encode CD4 and CD8 epitopes operably linked to a secretion signal.