COVID-19, which first appeared in Wuhan, China in December 2019, is relentlessly spreading around the world. The scale of the epidemic has caused chaos and led the World Health Organization to declare it a pandemic in March 2020.
Understanding the virus is the primary concern of scientists who are trying to unravel its secrets first, find ways to stop the spread of the disease, and find a vaccine. Scientists discover new findings every day about SARS-CoV-2, the virus behind the rapidly spreading disease COVID-19.
One area of investigation is the relationship with other corona viruses. For example, it was found to be part of the same family of coronaviruses that caused severe acute respiratory syndrome (SARS) and Middle Eastern respiratory syndrome (MERS) . SARS was first identified in 2002. It caused serious respiratory diseases that were fatal in about 1
Scientists who examined SARS-CoV-2 found that the structure is very similar to the SARS-CoV. But there are also a number of clear differences. For example, one of the most intriguing differences from COVID-19 is its rapid spread around the world.
Closing the gap in understanding these differences and similarities is what stands between scientists and a solution to the rapid spread of the disease. An important question of how the body can fight and overcome the infection is how blood groups – and the associated antibodies – can affect the immune response.
Similarities and differences
SARS-Cov-2 has a round shape and a series of proteins, which are called spikes on the surface. These spikes bind to the same human cell receptor (angiotensin converting enzyme 2) as the SARS-CoV. This information is important as it indicates that the virus uses the same mechanism to ensure that the viral genes enter the host cell, replicate and infect other cells. Scientists can use it to develop drugs that inhibit the binding of the spike protein and thus slow the replication ability of the virus.
Another similarity is the structure of the spike protein, which is referred to as NSP15. Scientists from a number of universities in the United States have studied the structure of this protein and found that it is 89% similar to the NSP15 protein in SARS-CoV .
Like COVID-19, SARS was highly contagious. But there was a peculiarity: Not everyone who was already exposed to infected developed the disease.
A research area was whether blood groups and naturally occurring antibodies can influence the spread or severity of the infection.
The distribution of the four main blood groups (A, B, AB and O) varies due to natural selection, the environment and the disease between population groups and geographical regions. Until recently, blood types were widely known for their role in blood transfusion. If patients received incompatible blood, strong naturally occurring anti-A or anti-B antibodies could cause a blood transfusion reaction .
However, studies have shown that blood groups can also play a role in infections and how the body's immune system reacts. One theory suggests that blood group antigens can act as binding receptors that allow viruses or bacteria to bind to and penetrate the body's cells.
An example of this is the Norovirus which causes severe vomiting and diarrhea. This virus can bind to ABO antigens on intestinal mucosal surfaces. Once this happens, it can get into the host cell and then replicate. On the other hand, anti-A and anti-B antibodies can be part of the body's natural defenses and limit or even prevent infection.
What about corona viruses?
Doctors in a hospital in Hong Kong investigated this phenomenon and reported that people with blood type O appeared to be less susceptible to SARS-CoV than people who were group A, B or AB. Researchers showed that the virus can express antigens on its surface in a manner similar to that in the ABH blood group. They also reported that naturally occurring anti-A antibodies could inhibit or even block the binding of the virus to the host cell.
This led to the theory that group O individuals who both have anti-A and anti-B antibodies can have some protection against infection.
The fact that blood groups and the associated antibodies influence the immune response is one of the lines of investigation as to how the body can fight and overcome the infection. How this happens in COVID-19 has to be examined in more detail in order to build on on the work already done .
Another discovery is that the SARS-CoV-2 spike protein is unique and is 10-20 times more likely to bind to human cells. This could explain the increasing and faster spread across populations.
The structure of these unique spike proteins is extremely important because they form the basis for the development of a vaccine.
The ABO blood group has evolved over thousands of years in response to disease. The antigens and antibodies that are part of this system interact with cells in the immune system and can affect their response. If we learn more about SARS-CoV-2, the role of blood groups, if any, may become clearer.
This article was created from The Conversation under a Creative Commons license. Read the original article .
Updated on: March 26, 2020 9:22:44 am IST
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