B.C. study investigates role of T cells in fighting COVID-19

I’ve given a lot for my career over the years. This time, I’m giving my blood to understand more about how our immune systems fight the coronavirus that has upended our lives.

I volunteered to have my blood tested for T cells as part of a local study on COVID-19 immunity being done by Vancouver research company Immunity Diagnostics.

T cells are a type of white blood cell that finds and destroys virus-infected cells. Immunity Diagnostics has been measuring T cell response in Metro Vancouver residents who have received their first doses of COVID-19 vaccines.

Studies around the world have shown that those who have a good T cell response did not get seriously ill when exposed to the virus.

As the world races to vaccinate as many people as possible, there are still questions about how long the immunity will last and how well the vaccines will work against new variants. That’s where T cells come in.

“Antibodies tend to decrease over time,” said Immunity Diagnostics founder Ismael Samudio. “Two to three boosters for everyone around the world is not sustainable. If we’re lucky, we may be able to have a long-lasting T cell response. If not, we have to figure out how to make vaccines with a long-lasting T cell response.”

Six weeks after my first dose of AstraZeneca, I rolled up my sleeve again to test how well my T cells would launch into virus fighting mode.

The T cell response was measured after blood samples were exposed to the spike protein of the SARS-CoV-2 virus that causes COVID-19. After a few days, I received the positive test results.

I was one of 80 per cent of Astrazeneca first dose recipients who showed a strong T cell response. Finally, some good news for our cohort.

As for Pfizer recipients, after one dose, only 20 per cent mounted a strong increase in T cells. Samudio says he was surprised by that, but points to a Pfizer study that indicates two doses are needed to get a comparable T cell response.

My results showed not only do I have a great response to the vaccine, I am one of 40 per cent of Lower Mainland residents tested who have been exposed to the virus or a similar coronavirus in the past – perhaps the common cold.

It looks like a good chunk of the population has some pre-existing immunity.

“That probably bodes well,” Samudio says. “The fact you have those T cells means you have a leg up, a head start.”

Samudio plans to get more samples from volunteers after their second dose and then publish his findings later this year. He says it’s too early to know how much T cell response gives us the protection we need, but he wants to be ready.

“I hope we don't get caught again unprepared for the next one,” he says.