Gaurav Gaiha, MD, DPhil, a member of the Ragon Institute of MGH, MIT and Harvard, studies HIV, one of the fastest-mutating viruses known to humankind. But HIV’s ability to mutate isn’t unique among RNA viruses — most viruses develop mutations, or changes in their genetic code, over time. If a virus is disease-causing, the right mutation can allow the virus to escape the immune response by changing the viral pieces the immune system uses to recognize the virus as a threat, pieces scientists call epitopes.
To combat HIV’s high rate of mutation, Gaiha and Elizabeth Rossin, MD, PhD, a Retina Fellow at Massachusetts Eye and Ear, a member of Mass General Brigham, developed an approach known as structure-based network analysis. With this, they can identify viral pieces that are constrained, or restricted, from mutation. Changes in mutationally constrained epitopes are rare, as they can cause the virus to lose its ability to infect and replicate, essentially rendering it unable to propagate itself.
When the pandemic began, Gaiha immediately recognized an opportunity to apply the principles of HIV structure-based network analysis to SARS-CoV-2, the virus that causes COVID-19. He and his team reasoned that the virus would likely mutate, potentially in ways that would allow it to escape both natural and vaccine-induced immunity. Using this approach, the team identified mutationally constrained SARS-CoV-2 epitopes that can be recognized by immune cells known as T cells. These epitopes could then be used in a vaccine to train T cells, providing protective immunity. Recently published in Cell, this work highlights the possibility of a T cell vaccine which could offer broad protection against new and emerging variants of SARS-CoV-2 and other SARS-like coronaviruses.
From the earliest stages of the COVID-19 pandemic, the team knew it was imperative to prepare against potential future mutations. Other labs already had published the protein structures (blueprints) of roughly 40% of the SARS-CoV-2 virus, and studies indicated that patients with a robust T cell response, specifically a CD8+ T cell response, were more likely to survive COVID-19 infection.
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Cell Reports. Pre-proof Research Paper (PDF file):
