How ‘killer’ T cells could boost COVID immunity in face of new variants

 

In the race against emerging coronavirus variants, researchers are looking beyond antibodies for clues to lasting protection from COVID-19.

Concerns about coronavirus variants that might be partially resistant to antibody defences have spurred renewed interest in other immune responses that protect against viruses. In particular, scientists are hopeful that T cells — a group of immune cells that can target and destroy virus-infected cells — could provide some immunity to COVID-19, even if antibodies become less effective at fighting the disease.

Researchers are now picking apart the available data, looking for signs that T cells could help to maintain lasting immunity.

“We know the antibodies are likely less effective, but maybe the T cells can save us,” says Daina Graybosch, a biotechnology analyst at investment bank SVB Leerink in New York City. “It makes sense biologically. We don’t have the data, but we can hope.”

Coronavirus vaccine development has largely focused on antibodies, and for good reason, says immunologist Alessandro Sette at the La Jolla Institute for Immunology in California. Antibodies — particularly those that bind to crucial viral proteins and block infection — can hold the key to ‘sterilizing immunity’, which not only reduces the severity of an illness, but prevents infection altogether.

That level of protection is considered the gold standard, but typically it requires large numbers of antibodies, says Sette. “That is great if that can be achieved, but it’s not necessarily always the case,” he says.

 

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