Immune memory allows our immune system to cope well with viruses and bacteria that have attacked our body in the past. Thanks to it, we gain immunity to previous infections. Its mechanisms are also the basis for the effectiveness of preventive vaccinations. How is immune memory produced? What is the process of acquiring disease resistance after being vaccinated?

The term"immune memory"describes the ability of the immune system to quickly recognize an antigen, a potentially dangerous substance. By this mechanism, the presence of potentially harmful intruders, such as pathogenic viruses and bacteria, is discovered. The use of immunological memory to fight microbes is possible only when an invasion of the same type has already occurred.

As they struggle with infection, specialized cells of the immune system remember the antigens of the microbes. Thanks to this, the body is able to defeat it efficiently the next time it comes into contact with the pathogenic factor.

Immune memory is created by everyone's immune system throughout their lives. The stimuli that initiate its development are situations of exposure to various factors potentially dangerous to he alth. By defeating them, the immune system learns to recognize the threat and fight it appropriately.

Immune memory is also the basis of the mechanism of action of immunization. In their course, antigens of viruses or bacteria are administered to the patient under controlled conditions. In this way, the immune system learns to fight these microbes. As a result of vaccinations, we acquire artificial immunity, which protects us against contracting specific diseases.

The name "artificial", when referring to the immunity that emerges after the administration of the vaccine, refers to the very process of administering the antigen to the patient. The immunological memory achieved in this way provides "natural" ways for our body to fight the threat.

Antigens and the formation of immune memory

Antigens are foreign substances that stimulate our immune cells to producespecific antibodies against them. This name covers glycoproteins that are capable of binding to hazardous molecules.

Recognition of specific hazardous substances by the immune system is extremely important. This process makes it possible to distinguish foreign cells from those that make up our bodies. In this way, immune cells learn that a virus or bacteria has invaded the body.

T lymphocytes and B lymphocytes have the ability to recognize previously known antigens. Thanks to this, they can neutralize them in a quick and efficient way. The activity of these cells is the basis for the functioning of immune memory.

Remembering information by the immune system

Infection triggers a primary immune response to fight the cause of the disease. When the microbial invasion is overcome, the body recovers, but the information about this event remains in the immune memory.

Specialized cells, memory lymphocytes, remain in our body ready to repel the enemy we already know. They react quickly and efficiently when they are re-infected. Thanks to this, they can prevent the development of a medical condition.

Formation of immune memory at the cellular level

Memory B lymphocytes are cells of the immune system with the ability to recognize antigens. They present them in the form of special peptide complexes, adjacent T lymphocytes. This leads to the activation of these cells and their rapid proliferation. The process is known as the primary immune response.

After the infection is defeated, the actively fighting cells involved in the primary immune response are eliminated. However, small amounts of antibodies raised in response to the threatening antigens remain. They are an element of immune memory and play an important role in the defense mechanism in the event of subsequent infections of the same microorganism.

In addition to antibodies, a small number of memory T and B cells remain in the body. They are the cellular element of immune memory. They continue after the infection in our body, remaining in a state of rest. In case of another meeting with an already known intruder, they are able to react immediately. Thanks to this, they are able to eliminate it before the disease process begins.

Memory cells have a long lifespan. They remain in the body even several dozen years after infection, ensuring immunity to the disease.

B lymphocytes and immune memory

The site of maturation of B lymphocytes is the bone marrow and lymph nodes. Then these cells move to the lymph nodes and the spleen. They play the role of precursors of plasmocytes, whose task is to produce antibodies. Some of these glycoproteins, left over from infections, form a component of the immune memory.

After multiplication, B lymphocytes differentiate into plasma and memory. The latter are one of the cellular components of immune memory.

T lymphocytes and immune memory

T cells mature in the thymus and then travel to the lymph nodes and the spleen. They are responsible for inducing a cell-type immune response. Their surface is covered with immunoglobulin receptors that act as antigen-binding antibodies.

T lymphocytes, in the course of infection, multiply and then differentiate into cytotoxic and memory. The latter type is an important element of cellular immune memory. Memory T cells store information about the known antigen for years after illness.

Naturally acquired active immunity

Naturally acquired active immunity is formed as a result of exposure to an invading microorganism. It is formed after overcoming bacterial and viral infections.

As a consequence of the pathogen's action, a primary immune response initially develops. This process ultimately leads to the development of an immune memory of the microorganism that triggered the immune response. It is a natural process of our body, arming itself to the next fight against pathogenic viruses and bacteria.

Many disorders of the immune system can negatively affect the formation of acquired active immunity. We can list here acquired or congenital immunodeficiency. The use of immunosuppressive drugs also disrupts this process.

Artificially acquired active immunity

Artificially acquired active immunity is induced by immunization. During them, the patient is given a specially prepared antigen of a suitable microorganism. Thereby, the vaccine stimulates the primary response to the antigen without causing disease symptoms. Ultimately, its adoption leads to the development of an immunological memory regarding a specific microorganism.

The effectiveness of vaccinations is based on imitating natural infections. Due to this mechanism, the development or strengthening of the body's resistance to the pathogen is achieved. The resulting immune memory is similar to whichit appears as a result of the first contact with a real threat, which is a bacterium or a virus.

The purpose of vaccination is for the patient to acquire active artificial immunity. Getting it protects against serious diseases.

The most important ingredient in all vaccines are antigens. They can be viruses, bacteria or their products such as toxins, polysaccharides or proteins. Contact with these substances allows for the formation of an immunological memory regarding the pathogenic microorganism.

Antigens in vaccines may be in the form:

  • live weakened microbes,
  • killed or inactivated microbes,
  • broken microorganisms or their fragments,
  • purified microbial proteins,
  • recombinant genetically engineered proteins,
  • purified polysaccharides,
  • bacterial toxins.

Vaccines containing live, weakened microorganisms cause a strong reaction in the body. After their administration, resistance to disease is possible even after a single dose. Usually, however, their intake is associated with more severe side effects than other types of vaccination.

Other types of vaccines that contain dead organisms or their ingredients provide immunity after several doses at appropriate intervals.

Introducing an antigen into the body stimulates immune cells to produce appropriate antibodies against it. As a result of the defensive processes, immune memory cells are also formed. Thanks to them, a long-lasting effect of preventive vaccination is possible.

Safety of acquiring immune memory through vaccination

Immunity acquired against infectious diseases, obtained as a result of preventive vaccinations, is similar to that emerging after an infection. These two ways of shaping immune memory are based on the same natural mechanisms of our body's immune responses.

The immune immunity obtained by vaccination is referred to as "artificial". However, this name refers to the method of controlled contact with the antigen itself. Learned in this process, the methods of dealing with microbes are completely "natural" for our bodies.

"Natural" immunity is acquired through infections that are often dangerous. Getting sick with an infectious disease is sometimes also associated with serious complications. Side effects appearing as a consequence of routine vaccinations are in the vast majority of casesmild.

Serious complications are extremely rare. Shaping immune memory by administering a vaccine is therefore much safer than acquiring it through "natural" infection.

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Immune system