Immunology experts recently released a paper suggesting that coronavirus immunity might be possible through a different genetic pattern of SARS, or the common cold. They claim that this possible immunity may last up to 17 years.
Coronavirus related symptoms that mimic the common cold, called betacoronavirus, may either have immunity or be infected by a milder form of the virus. Betacoronaviruses, specifically OC43 and HKU1, are the cause of common colds as well as severe chest infections, leaving the young and elderly in critical conditions.
The beta virus has similar genetic features with its SARS family, such as COVID-19 and Middle East Respiratory Syndrome (MERS). If an individual had been previously exposed to the common cold, the body develops memory T cells, which become a defense system when a similar infection enters the body, resulting in immunity.
T cells, a type of white blood cell, is a prominent part of the immune system, adjusting the body to respond to specific attacking pathogens. Because of their ability to create lasting shields against viruses, they are called 'memory cells.'
Professor Antonio Bertoletti, an immunologist from the Duke-NUS Medical School in Singapore, and his team have new findings on the function of T cells amidst the global pandemic. They discovered that patients who survived the SARS lung virus in 2003 had immune responses to COVID-19 antibodies.
Helper T Cells
'These findings demonstrate that virus-specific memory T cells induced by betacoronavirus infection are long-lasting, which supports the notion that COVID-19 patients would develop long-term T cell immunity,' said the team. 'Our findings also raise the intriguing possibility that infection with related viruses can also protect from or modify the pathology caused by SARS-Cov-2 [the strain of coronavirus that causes COVID-19].'
Four blood samples were taken from coronavirus patients who had recovered, 23 who has SARS, and 18 individuals who had exposed to neither deadly viruses.
What surprised Bertoletti's team was that 50% of unexposed patients had defensive T-cells which could defend their immune system against the betacoronaviruses SARS and COVID-19. Most likely, the scientists concluded, their immunity developed memory cells from obtaining common colds caused by betacoronavirus or other unknown pathogens.
In another study of T cell immunity, virologist Angela Rasmussen of Columbia University agrees with the Singaporean team. Alongside Shane Crotty and Alessandro Sette, immunologists at the La Jolla Institute for Immunology, bioinformatic tools were used to predict which viral protein fragments would trigger the strongest T cell responses.
Ten recovered patients were exposed to the immune cells where their 'helper T cells...recognized the SARS-CoV-2 spike protein.' 'The immune system sees this virus and mounts an effective immune response,' said Sette. Rasmussen said, 'these papers are really helpful because they start to define the T cell component of the immune response.'
New insight on adaptive immunity against coronavirus antibodies is the key to developing a 'vaccine design and evaluation of candidate vaccines,' notes Bertoletti's study. Moreover, understanding more about immunity today will be important for 'epidemiological model calibration of future' pandemics and social distancing measures.