In a new study, researchers have uncovered how a crucial component of the immune system responds to the spike protein of COVID-19 virus —important information for future validation of vaccine candidates.
The research was conducted by a team from the Peter Doherty Institute for Infection and Immunity (Doherty Institute).
Coronavirus particles have a corona (crown) of proteins that resemble spikes, which enable the virus to attach and enter cells in humans.
The spike protein is crucial in inducing neutralizing antibodies to protect from re-infection.
Neutralizing antibodies not only bind to the viral spike protein but prevent it from being able to attach to and enter human cells.
Generating a strong neutralizing antibody response is an important goal for SARS-CoV-2 vaccines.
The spike protein is the target for most of the current COVID-19 vaccine human clinical trials.
In the study, the team tested how the immune system, particularly B and T cells, respond to the spike.
B cells are responsible for producing the antibodies that recognize SARS-CoV-2, while T cells play an important role in supporting the development of the B cell response.
The team looked at people who had recovered from COVID-19 who had mostly experienced mild or no symptoms, as that kind of immune response mimics what a vaccine might induce.
They found that those who showed strong neutralizing antibody activity had a robust B cell response, but most surprisingly, they also found that a particular subset of T cells, called T-follicular helper cells, was a great predictor of an effective immune response.
The research team hopes the ‘immune parameters’ they’ve identified can be applied to clinical vaccine trials to assess whether or not a vaccine might induce a strong or weak neutralizing antibody response.
They say that they have biomarkers or predictors of what elicits a good or poor immune response to COVID-19, and they can look at the vaccine candidates and see what will offer the best protection.
In addition to COVID-19, the researchers also looked at circulating coronaviruses that cause the common cold in an effort to understand what would predict the neutralizing response to SARS-CoV-2.
These findings were consistent with what was described in the immune responses of other people who had recovered from COVID-19.
One author of the study is the University of Melbourne Dr. Jennifer Juno, a postdoctoral researcher at the Doherty Institute.
The study is published in Nature Medicine.
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