Are T cells more important than antibodies in fight against coronavirus?

A new study published in the journal Cell has emphasised the critical nature of T cells over antibodies while fighting off the novel coronavirus.

For the study, researchers at the La Jolla Institute for Immunology collected blood samples from 50 Covid-19 patients.

They analysed all three branches of the adaptive immune system — B cells that produce antibodies; CD4+ T cells (helper T cells); and CD8+ T cells (cytotoxic T cells and killer T cells). The cohort included cases across a range of Covid-19 disease severities.

The researchers found that broad and coordinated adaptive immune responses among the three branches of the immune system were associated with lesser Covid-19 disease severity.

Also read: Covid-19: Higher viral loads likely to increase risk of death among hospitalised patients, says study

Their study noted that CD4+ and CD8+ T cells are key to the control and clearance of acute infection and can help elicit high-quality neutralising antibodies.

Co-author and post-doctoral researcher Carolyn Moderbacher, said in the study: “When we looked at a combination of all of our data across all 111 measured parameters, we found that, in general, people who mounted a broader and well-coordinated adaptive response tended to do better.”

She added: “A strong SARS-CoV-2 specific T cell response, in particular, was predictive of milder disease. Individuals whose immune response was less coordinated tended to have poorer outcomes.”

The researchers said in their study that the low number of naïve T cells was also associated with severe Covid-19 disease in the cohort.

Researchers explained that as people grow old, the reservoir of naïve T cells dwindles, and as fewer cells are available for activation, it can become increasingly difficult to respond to new pathogens.

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Senior author Shane Crotty, professor at the La Jolla Institute Centre for Infectious Disease and Vaccine Research, said in a statement: People over the age of 65 were much more likely to have poor T cell responses and a poorly coordinated immune response, and thus have much more severe or fatal Covid-19.”

“Thus, these findings indicate it is plausible T cells are more important in natural SARS-CoV-2 infection, and antibodies more important in a Covid-19 vaccine, although it is also plausible that T cell responses against this virus are important in both cases," Crotty added.

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