While some have only heard the term ‘Coronavirus’ starting in 2020, the drama around this type of infectious disease is not new. This type of virus brings on illnesses that you have most likely contracted long before the start of the pandemic in March of 2020. For example, the common cold. But of course, Coronavirus is not responsible for just that– they also bring on SARS (severe acute respiratory syndrome) and MERS (middle eastern respiratory syndrome). With SARS-CoV-2 being the virus that causes COVID-19, this extremely contagious disease is, in fact, a strain of SARS.
But if the Coronavirus has been around long before now and there are so many types of it, what makes SARS-CoV-2 special? The answer to this is its relationship with a particular enzyme, ACE-2, whose shape, function and location opens doors right up for COVID-19 to enter and infect our healthy cells.
While other types of SARS also attached to this enzyme, the ingenious design of the SARS-Cov-2 protruding spike protein is what makes this virus particularly contagious; Throughout the evolution of this virus from other versions of SARS, the shape of their spike protein has become more refined and specific through compaction of its structure to better mimic the shape of the receptor dock of a naturally-occurring enzyme called ACE-2. This mutation allows the virus to strengthen the grip that they can have on human’s cells, making their infection rate much more high and effective.
The function and location of ACE-2 also practically facilitates the infection of SARS-CoV-2 within us. These enzymes play a critical role in the renin-angiotensin system (infection-fighting system), and while this virus utilizes them as an entrance to the body as a means to infect, it is reducing the function of the very cells that are supposed to be fighting it. Additionally, this suppresses the rest of the functions of our immune system.
In the human body, one way in which our immune system works is by the release of T lymphocytes, or T-cells, along with macrophages and monocytes to fight off infections. However, with SARS-CoV-2 having already hijacked ACE-2 at the time when T-cell release is activated, the immune system becomes dysfunctional; the three aforementioned immunity cells are released via a positive feedback loop in a much greater magnitude than usual/ than with other illnesses. Lastly, ACE-2 positive cells are present in over 70 types of our bodily cells, and are especially abundant in oral, nasal, and nasopharynx tissues, which are hot spot entrances for this virus (and many others).
With the involvement of just one enzyme within our bodies, SARS-CoV-2 throws all aspects of our immune system into a disarray. With the many adaptations and evolutions of SARS viruses, infectious diseases such as these are just getting smarter and smarter each time they sweep through the human population.
SARS-CoV-2 Spike Protein