Discovery of Precise T Cell Targets in COVID-19 Convalescent Patients to Help Develop Vaccines and Diagnostics

Scientists have identified the precise targets of T cells isolated from COVID-19 convalescent patients, thereby paving the way for the development of next-generation vaccines and T cell-based diagnostics.

The targets were identified by TScan Therapeutics (Waltham, MA, USA), a biopharmaceutical company focused on the development of T cell receptor (TCR)-engineered T cell therapies in oncology, using its high-throughput TCR target discovery platform. Leveraging its core T cell target identification technology, TScan mapped the memory CD8+ T cell responses of convalescent COVID-19 patients, with a focus on the six most prevalent HLA types. For each HLA type, patient T cells largely recognized the same three to eight immunodominant epitopes. Importantly, a majority of the identified T cell targets were not found in the spike protein of the virus, the target of most vaccines currently in development. Additionally, these immunodominant targets were not found in other coronaviruses, limiting the likelihood that prior coronavirus infections may confer immunity to COVID-19.


The findings have been submitted for scientific review and publication with the goal of guiding COVID-19 vaccine development that may confer broad, durable immunity by eliciting a robust T cell response. These discoveries may also enable the development of reliable T cell-based diagnostic tests to determine longer-term immunity and inform the development of therapeutic agents.

“When the pandemic began, we realized very quickly that our platform technology was well suited to rapidly identify the dominant T cell targets for COVID-19. We are hopeful these data will aid in the progress of developing vaccines with durable protection, as well as therapeutics and diagnostics,” said David Southwell, Chief Executive Officer at TScan. “In a matter of three months we were able to collect patient samples and effectively leverage our platform technology to make these important discoveries. We are in discussions with diagnostic, therapeutic and vaccine developers to advance these discoveries into solutions that help bring an end to this pandemic.”

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TScan Therapeutics