Defining epitope coverage requirements for T cell-based HIV vaccines: theoretical considerations and practical...

Area of Science:

• Immunology
• Virology
• Vaccine Development

Background:

• Human Immunodeficiency Virus (HIV) exhibits significant genetic diversity and plasticity, posing challenges for vaccine development.
• Candidate T cell-based vaccines require rigorous assessment of their potential to cover diverse HIV strains.

Purpose of the Study:

• To develop and utilize a model for assessing the potential HIV strain coverage of T cell-based vaccine candidates.
• To explore vaccine coverage requirements based on T cell epitope breadth and depth.

Main Methods:

• An N-mer identity algorithm was employed to represent T cell epitopes.
• Analyses of epitope breadth (number of epitopes) and depth (variant coverage) were integrated to model vaccine coverage.

Main Results:

• Considering multiple epitope generation provides a more nuanced assessment of vaccine strain coverage.
• Epitope breadth requirements for vaccine coverage are manageable, even for natural sequence-based vaccines.
• Increasing vaccine valency (number of epitope variants) significantly reduces epitope requirements for coverage.
• Multiple-hit models increase epitope breadth requirements, potentially limiting low-valency natural sequence-based vaccines.

Conclusions:

• A calculable metric for minimum epitope count to achieve desired coverage can be derived by comparing vaccine sequences against incoming virus datasets.
• Proposed analyses can guide early-stage planning and execution of vaccine trials to evaluate theoretical and empirical suitability.