Could ‘Helper’ T Cells Pave the Way for COVID-19 Immunity?

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A study published last month in the journal Cell suggests that some people may have immune systems that are better prepared to fight the novel coronavirus than others. Researchers found that certain individuals who have never been exposed to COVID-19 appear to have “helper” T cells that are capable of recognizing and responding to the virus.

The scientists believe that the likeliest explanation is cross-reactivity. This occurs when helper T cells are developed in response to a different virus, but react similarly to previously unknown pathogens. This also suggests that those T cells may be left over in individuals’ previous exposure to a different coronavirus, likely one that causes the common cold.

“Vaccine development against acute viral infections classically focuses on vaccine-elicited recapitulation of the type of protective immune response elicited by natural infection,” wrote the authors of the report. “Such foundational knowledge is currently missing for COVID-19, including how the balance and the phenotypes of responding cells vary as a function of disease course and severity. Such knowledge can guide selection of vaccine strategies most likely to elicit protective immunity against SARS-CoV-2. Furthermore, knowledge of the T cell responses to COVID-19 can guide selection of appropriate immunological endpoints for COVID-19 candidate vaccine clinical trials, which are already starting.”

The hunt for a COVID-19 vaccine has heated up in recent months, with Cambridge-based Moderna, Inc. leading the way with breaking news back on May 18. The clinical stage biotechnology company announced positive results from a Phase 1 study looking at the effectiveness of mRNA-1273, its vaccine candidate against novel coronavirus.

Overall, the mRNA-1273 was well tolerated and evaluated as safe in experimentation. Based on the Phase I data, a Phase II study will be amended to study two dose levels: 50 µg and 100 µg. The goal will be to select a dose for pivotal trials.

“With today’s positive interim Phase 1 data and the positive data in the mouse challenge model, the Moderna team continues to focus on moving as fast as safely possible to start our pivotal Phase 3 study in July and, if successful, file a BLA,” said Stéphane Bancel, Chief Executive Officer at Moderna, at the time of the Phase 1 data announcement. “We are investing to scale up manufacturing so we can maximize the number of doses we can produce to help protect as many people as we can from SARS-CoV-2.”

AstraZeneca also announced new initiatives in the fight against COVID-19 back on May 21. The company stated that it is working on several agreements to ensure that there is broad and equitable supply of a future vaccine globally at no profit during the pandemic. In addition, AstraZeneca shared that it had received $1 billion from the U.S. Biomedical Advanced Research and Development Authority for the development, production and delivery of a vaccine, beginning in the fall.

The company’s recombinant adenovirus vaccine, known as AZD1222, is being studied in more than 1,000 healthy volunteers in a number of different trial centers across southern England. AstraZeneca finalized its license agreement with Oxford University for the vaccine in May as well.

“This pandemic is a global tragedy and it is a challenge for all of humanity,” said Pascal Soriot, Chief Executive Officer, AstraZeneca. “We need to defeat the virus together or it will continue to inflict huge personal suffering and leave long-lasting economic and social scars in every country around the world.”

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