The immune system has been the main subject of research within the medical-scientific community and the recent discovery of two vaccines for Covid-19 by BioNTech, in collaboration with Pfizer, and by Moderna respectively contributed to the spread of this term in the news these days.
The immune system is the most important mechanism of defence of our body since its function is to prevent or limit infection by distinguishing and eliminating harmful molecules and cells from the body, such as bacteria, viruses, toxins and damaged cells deriving from cancer.
Mechanisms of defence and the role of vaccines
The immune system is complex and pervasive. The skin, cornea and mucosa of the respiratory, gastrointestinal and genitourinary tracts are the body’s first line of defence. Other lines of defence are lymphocytes, which are in charge of the generalised destruction of invaders, and antibodies, specialised cells developed by B-lymphocytes, representing our specific resistance. The immune system can be:
- innate, namely inherited, and it responds immediately to an invader by killing it through phagocytes, innate lymphoid cells and polymorph nuclear leukocytes;
- acquired, which requires a first exposure to an antigen in order to trigger a specific response by developing antibodies. Thereafter, the immune system remembers past exposure and develops antigen-specific response (immunological memory).
Differently from the innate system, the acquired immune system changes throughout our life and the process of immunisation can take place under different situations.
Active immunisation through vaccines prevents 2-3 million deaths every year and it is the most efficient defence against viruses since it trains and prepares the immune system by inserting an antigen in the body. Once the system is ready to destroy a target, it will prevent illness. This justifies the unprecedented speed in developing a Covid-19 vaccine since it is the only way to protect individuals from the virus infection.
With this regard, the President of the European Commission, Ursula von der Leyen, has announced that there are currently five agreements with pharmaceuticals companies and a potential sixth one for the Covid-19 vaccine. If vaccines have proven safe and effective against Covid-19, every Member State will receive doses “at the same time, on a pro-rata basis, and under the same conditions.”
Did you know?
One of the main consequences of the Covid-19 virus is a fulminant and damaging reaction by the immune system. When there is an infection, the immune system activates an inflammatory response aiming at producing antibodies. During this phase, other substances called pro-inflammatory cytokines are produce in order to suppress the infection. However, it has been discovered that interleukin-6 (IL-6), one of the main mediators and cytokines of the inflammatory and immune response, is overproduced in patients with Covid-19. This phenomenon is known as “cytokine storm” and consists in an extreme reaction by the immune system, which begins to fight against itself and spreads from the site of infection to the entire body. Eventually, this phenomenon triggers a self-alimented process of destruction called Multiple Organ Failure (MOF) syndrome, which leads to death.
This week, you can tune in to another IATE goes Audio feature: click below to listen to ‘Immune System’ explained in English.
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Written by Diandra Falchieri