CMV Vectors for Broad CD8+ T Cell Targeting
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Solution Overview
Problem
Current HIV/AIDS vaccines fail to effectively elicit CD8+ T cell responses that target vulnerable epitopes across diverse MHC-I haplotypes, leading to immune evasion by viruses like HIV and SIV, and have not achieved substantial modification of CD8+ T cell immunodominance hierarchies or establishment of protective responses in most individuals.
Innovation Solution
Development of recombinant cytomegalovirus (CMV) vectors that express HIV proteins, specifically lacking UL128 and UL130 proteins, to induce CD8+ T cell responses that target novel epitopes presented by both MHC-I and MHC-II, thereby generating broad and durable HIV-specific effector memory T cell responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional vaccines are used to elicit CD8+ T cell responses, then the vaccine structure is simple and easy to manufacture, but the T cell responses are narrow and fail to target vulnerable epitopes across diverse MHC-I haplotypes
Solution Approach 1:
The vaccine vector is segmented into modular components: a CMV backbone providing persistence and immune modulation, heterologous antigen genes encoding multiple epitopes, and optional MHC-binding peptides. This segmentation allows systematic expansion of epitope recognition breadth while maintaining manageable vector complexity through standardized modular units that can be combined针对不同MHC haplotypes and pathogens.
Solution Approach 2:
The CMV vector serves multiple functions simultaneously: it acts as a persistent expression system for continuous antigen presentation, provides immune modulatory properties through viral proteins, delivers heterologous antigens across diverse MHC haplotypes, and enables broad CD8+ T cell recognition. This multi-functionality resolves the contradiction by consolidating multiple capabilities into a single versatile platform rather than requiring separate simple vaccine components.
2Reliability
If CMV vectors expressing HIV proteins are used to generate broad CD8+ T cell responses, then the T cell response breadth increases 3-fold, but the vector design complexity increases due to need to control UL128 and UL130 expression
Solution Approach 1:
The harmful UL128 and UL130 proteins that suppress MHC-II restricted CD8+ T cell responses are extracted (removed or inactivated) from the CMV vector genome. This extraction eliminates the immunosuppressive effect while preserving the desired persistent expression and immune stimulation properties, thereby achieving durable virologic control without the complicating factor of these inhibitory proteins.
Solution Approach 2:
The expression levels and timing of viral proteins are precisely controlled by modifying promoter strength, adding regulatory elements, and adjusting gene dosage in the CMV vector. By changing these parametric properties of vector expression, the patent optimizes antigen presentation durability while managing the complexity of coordinating multiple viral protein expressions to achieve reliable long-term control.
3Productivity
If CMV vectors lacking UL128 and UL130 are used to induce MHC-II restricted responses, then the CD8+ T cell response targets novel epitopes with immediate virologic control, but the manufacturing precision requirements increase
Solution Approach 1:
The CMV vector is pre-designed with optimized promoter sequences, enhancer elements, and regulatory regions that ensure immediate and high-level antigen expression upon infection. This preliminary optimization of expression control elements guarantees rapid production of heterologous antigens and swift activation of CD8+ T cell responses, achieving immediate virologic control while establishing clear manufacturing specifications for vector production quality.
Data Source
AI summary
CMV vectors comprising a heterologous protein antigen, an active UL131 protein (or an ortholog thereof), and an active UL128 protein (or an ortholog thereof) but lacking an active UL130 protein (or an ortholog thereof) are provided. CMV vectors comprising a heterologous protein antigen, an active UL131 protein (or an ortholog thereof), and an active UL130 protein (or an ortholog thereof) but lacking an active UL128 protein are also provided. In addition, methods of using CMV vectors to generate an immune response characterized as having at least 10% of the CD8+ T cells directed against epitopes presented by MHC Class II are provided.