Seasonal colds are no fun by all means, but recent research indicates that the colds you’ve had in the past could have some COVID-19 security. The research, published at the University of Rochester Medical Center by infectious disease experts, also indicates that immunity to COVID-19 is expected to last a long time, perhaps even a lifetime.
The research, published in mBio, is the first to show that memory B cells, long-lived immune cells that recognize pathogens, produce antibodies to kill them, and recognize them for the future, are induced by the COVID-19-causing virus, SARS-CoV-2. These memory B cells will jump into action even quicker to kill the infection until it begins the next time the pathogen attempts to reach the body.
They could protect COVID-19 survivors from subsequent infections for a long time because memory B cells can live for decades, but further studies will have to prove that.
The study is also the first to record memory B cell cross-reactivity, indicating that B cells that once targeted cold-causing coronaviruses also tended to recognize SARS-CoV-2. The authors of the study claim that this may indicate that someone infected with a common coronavirus, almost anyone, will have some degree of previously established resistance to the virus.
The results of the study are based on a comparison of blood samples obtained six to 10 years ago from 26 individuals suffering from mild to moderate COVID-19 and 21 healthy donors whose samples were collected well before they may have been exposed to COVID-19. The study authors measured levels of memory B cells and antibodies from these samples that target particular parts of the Spike protein that occurs in all coronaviruses and is essential for helping to infect cells with viruses.
In each coronavirus, the Spike protein looks and behaves a little differently, but one of its elements, the subunit S2, remains pretty much the same across all the viruses. Memory B cells can’t understand the difference and strike between the Spike S2 subunits of the various coronaviruses. For beta-coronaviruses, a subclass that includes two cold-causing viruses as well as SARS, MERS, and SARS-CoV-2, the study found that this was valid.
The level of security offered by cross-reactive memory B cells and how it affects patient outcomes is what this study does not reveal.