With the COVID-19 disease pandemic still a global threat, researchers from around the world are frantically trying to develop a vaccine, while epidemiologists are trying to predict how the pandemic will continue over time. What is not yet known is if the human immune system can produce a lasting response to SARS-CoV-2.
A group of researchers from the labs of Alessandro Sette, Dr. Biol. Sci. and Shane Crotty, Ph.D., at La Jolla Institute for Immunology have been able to provide the first cellular immunology data, which will help shape social distancing guidelines. The study is published in the online edition of the journal, Cell. It describes a strong immune response to SARS-CoV-2 based on a group of 20 adults who recovered from the disease. This finding means that an effective vaccine is possible.
Says Sette, "If we had seen only marginal immune responses, we would have been concerned. But what we see is a very robust T cell response against the spike protein, which is the target of most ongoing COVID-19 efforts, as well as other viral proteins. These findings are really good news for vaccine development."
Sette and his team ran a previous study that used bioinformatics tools to predict which parts of the SARS-CoV-2 virus can activate T cells. Then, in the current study, they tested to see if T cells taken from patients who recovered from COVID-19 could recognize the fragments from the virus. "We specifically chose to study people who had a normal disease course and didn't require hospitalization to provide a solid benchmark for what a normal immune response looks like, since the virus can do some very unusual things in some people," says Sette.
The scientists found that all the COVID-19 patients had a “helper” T cell response, which aids in the production of antibodies. Almost all of them also produced “killer” T cells, which destroy the cells infected by the virus. Says Crotty, "Our data show that the virus induces what you would expect from a typical, successful antiviral response.”
As Sette explains, "We have a solid starting foundation to now ask whether there's a difference in the type of immune response in people who have severe outcomes and require hospitalization versus people who can recover at home or are even asymptomatic. But not only that, we now have an important tool to determine whether the immune response in people who have received an experimental vaccine resembles what you would expect to see in a protective immune response to COVID-19, as opposed to an insufficient or detrimental response."