Acquired Immunity: What Is It?
The immune system, both innate and acquired, is the foundation of our health. What does acquired immunity consist of? Can it be strengthened over time? Answering these questions is essential if we are to enjoy a healthy life and keep disease at bay.
Symptoms such as recurring colds and fevers or relapsing bacterial infections can be indicative of a weak immune system. According to the American Academy of Allergy, Asthma and Immunology, more than three episodes of bacterial sinusitis or more than two antibiotic treatments per year are indicative of immune problems.
Our natural barriers
The human body has other containment barriers besides the immune system. These are divided into three types:
- Primary barriers. Several studies consider the skin a first containment barrier against possible pathogens. Lipids and keratin make the epidermis a real containment wall against viruses and bacteria.
- Secondary barriers. If the primary mechanisms fail, neutrophils and macrophages (white blood cells) have the job of enveloping and destroying pathogens. This mechanism is known as phagocytosis, a clear example of a secondary barrier.
- Tertiary barriers. Many structures produced by pathogens are recognized by T and B lymphocytes which effectively deactivate and destroy them.
This distinction between biological barriers is essential, as it allows us to understand that the acquired immune system falls into the tertiary biological barrier category.
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What is acquired immunity?
The acquired immune system is a collection of highly specialized cells and systemic processes capable of preventing or eliminating pathogens. It is a unique system of vertebrate beings.
Its function is to recognize germs in a specific way in order to be able to fight them more effectively and quickly. Surprising as it may seem, this biological barrier is endowed with memory, as the response to the same pathogen becomes more and more powerful.
What elements is it made of?
The agents of this protective system are T lymphocytes and B lymphocytes (blood leukocytes) produced in the thymus and bone marrow, respectively. The acquired immune system cannot be understood without the innate one.
As pointed out by various sources, in fact, the cells of the innate immune system produce antigens (substances of viral and bacterial origin) and present them to the lymphocytes so that they react accordingly. In order not to complicate things too much, we will limit the importance of lymphocytes to two concepts:
- Each lymphocyte has a receptor for each antigen presented by the pathogen.
- This information is replicated with each new generation of these cells. It also defines an increasingly effective defense system with each wave of infection.
Symptoms of a weakened immune system
As anticipated, various symptoms can make us think that the acquired immune system is not working as it should. Some are:
- Need for more than two antibiotic treatments per year.
- More than four ear infections during the year.
- Development of close pneumonia.
- Three or more episodes of chronic sinusitis each year.
- Need for preventive antibiotic treatments to reduce the risk of infection.
- Severe infections starting with common bacterial diseases.
In these cases it is essential to schedule a medical check-up as soon as possible. The results should be evaluated by an immunologist to determine the cause of the immunosuppression.
How to strengthen a weakened immune system?
The best way to strengthen this tertiary barrier is none other than exposure to pathogens. This does not mean that we have to go “disease hunting” . In fact, vaccines were invented for this purpose.
The World Health Organization (WHO) explains that vaccines are prepared with weakened or killed forms of pathogenic microorganisms. These are able to stimulate the production of antibodies (receptors for the lymphocytes mentioned above) once introduced into the human body.
The acquired immune system responds to these stimuli as it destroys and remembers the possible threats present in vaccines, even if these do not represent a real danger to the patient. This way, when the body is in the presence of the true pathogen, the lymphocytes will recognize it immediately before an infection develops.
Acquired immunity: to remember …
Acquired immunity is a very important biological barrier because it protects humans from a multitude of pathogens. For this reason it is essential to inquire about the treatments available and vaccination schedules.
Vaccines not only protect us by promoting the specialization of the acquired immune system, but also create a herd immunity that protects the weakest categories and the sick.
