Acquired Immunity: Description And Characteristics

The immune system, both congenital and acquired, is essential for optimal health. But what does acquired immunity consist of? How is it strengthened over time? Getting answers to these questions is essential in order to enjoy a life free of disease. Read on to find out more about it.

Symptoms such as a persistent cold, recurrent fever and recurrent bacterial infections may be signs of a weakened immune system. According to  the American Academy of Allergy, Asthma, and Immunology  , more than three episodes of bacterial sinusitis or more than two treatments with antibiotics a year cause problems with the immune system.

About biological barriers

The human body possesses barriers as parts of the immune system. There are three types:

• Primary barriers. According to several studies, the skin is the first barrier to possible pathogens. Lipid and keratin are elements in its composition that make the epidermis a wall against viruses and bacteria.

• Secondary barriers. When the primary mechanisms fail, neutrophils and macrophages (white blood cells) are responsible for enveloping and destroying pathogens. We know this as phagocytosis and it is a clear example of a secondary barrier.
• Tertiary barriers. T and B lymphocytes recognize many structures produced by pathogens and inactivate or destroy them effectively.

This distinction between biological barriers is essential. This is because it allows us to understand that when we talk about acquired immunity, we are talking about tertiary biological barriers.

The acquired immune system is a tertiary biological barrier that attacks pathogens that try to infect the body.

What is acquired immunity?

As you can see, the acquired immune system is defined as a set of highly specialized cells and systemic processes that eliminate or avoid pathogenic threats. This system is unique to vertebrates according to this article on immunology.

Its function is to recognize bacteria in a specific way in order to be able to fight them quickly and more effectively. Although it may seem surprising, one can say that this biological barrier has a memory, as the reaction to the same pathogen becomes more powerful upon repeated exposure.

Its elements

The effectors of this protection system are T and B lymphocytes (white blood cells). They are produced in the thymus and bone marrow, respectively.

The acquired immune system cannot be understood without the innate. As several sources point out, it is the cells in the innate system that process the antigens (the substances from viruses and bacteria) and present them to the lymphocytes. This is how they act in accordance with each other.

In order not to make it more complicated, we will limit the importance of lymphocytes to the following:

• Each type of lymphocyte has a receptor for each antigen present in the pathogen.
• This information is copied into each new generation of these cells, creating an even more effective defense system against each wave of infection.

Symptoms of a weakened immune system

As expected in the beginning, there are several signs that may give suspicion that the acquired immune system is not working as it should. Some of them are:

• More than two treatments with antibiotics a year.
• More than four ear infections a year.
• The development of two cases of pneumonia close to each other.
• Three or more episodes of chronic sinusitis per year.
• A need for preventative antibiotics to reduce the risk of infections.
• Lastly, there is the development of serious infections from common bacterial disorders.

If these aspects are met, a patient must undergo an immediate medical examination. The results will be reviewed by an immunologist, who will be able to diagnose the underlying cause of the weakened immune system.

How to acquire immunity

As you have seen, the most effective way to strengthen this tertiary barrier is nothing more than by exposure to pathogens. This does not mean that you should get sick, because vaccines already serve this purpose.

According to the World Health Organization (WHO)  , vaccines are agents with attenuated or dead forms of harmful microorganisms  that promote the stimulation of antibodies (receptors for the aforementioned lymphocytes) when introduced into a human body.

The acquired immune system responds to these stimuli as they destroy and remember the possible threats that are in vaccines. However, they do not pose a real danger to the patient. Thus, when the actual pathogen is present, the lymphocyte will recognize it immediately before the infection begins.

Vaccination plays a very important role in strengthening an acquired immune system.

Things to keep in mind about acquired immunity

Acquired immunity is an extremely important tertiary biological barrier. This is because it repeatedly protects humans from a myriad of pathogens. It is therefore essential to be familiar with and follow the vaccination programs in your country.

Lastly, vaccines not only protect us by promoting the specialization of our acquired immune system. They also create the kind of herd immunity that protects the weakest and sickest.

Thanks for reading.