A strong immune system can resist viruses and bacteria. Which makes some people more resistant and not getting sick, while others have a weak immune system and constantly get sick. What determines the body's resistance?

Immunity - types of immunity

1.Non-specific (innate) immunity - is the body's first line of defense against germs

There is a skin on the front line to protect us. Undamaged, it is an effective barrier to pathogenic microorganisms. The sweat on it contains substances with a bactericidal effect, as well as saliva and tears.

The body's immunityis the body's ability to defend itself against external pathogens (e.g. bacteria, viruses, toxins) or internal (mutated cells, cancerous cells). If it is weak, it cannot resist microbial attack. Then, the germs settle in the respiratory tract, damaging the mucosa of the nose, throat and larynx, or they travel further - to the bronchi or lungs, causing inflammation. And if the immune system is too active, autoimmune diseases or allergies can develop.

The immune system is not located in one place in our body. Its cells are scattered throughout the body. There are, among others in the thymus, spleen, lymph nodes.

In turn, the respiratory tract is protected by a delicate layer of mucus and tiny cilia that transport all impurities and expel them outside. On the other hand, microorganisms that enter the body with food are destroyed by acid secretions and gastric enzymes.

2.Specific (acquired) immunity

When the body fails to resist an attack by pathogenic pathogens and they overcome the first line of defense, specific (acquired) immunity is activated. The immune system begins to produce cells to identify and destroy any "foreign bodies" (called antigens) that have entered the body through the mucous membranes of the throat, nose, digestive tract or other routes. Immune cells arise in various organs and have their speci alties:

  • Monocytes are white blood cells that are produced in the bone marrow. When they spot an intruder (antigen), they start to approach it.During this journey, they transform into macrophages and as such devour the antigen, and transmit information about its appearance to lymphocytes;
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We build our own immunity by vaccinating against a specific disease or … getting sick.

  • T cells mature in the thymus. They inform other cells about the presence of antigens and at the same time fight the intruder directly;
  • B lymphocytes are produced in the bone marrow, spleen and lymph nodes. When bacteria or viruses appear, they react by producing antibodies that destroy the enemy.

Once our body is infected by a pathogenic microorganism (e.g. a virus, bacteria), it will form the so-called immune memory cells. When this microorganism attacks us again - it will be recognized and destroyed by the immune intelligence. This means that we build our own immunity by being sick. Specific immunity is also acquired after administration of a vaccine (e.g. against rabies, measles, rubella, pertussis), as well as after injection of antiserum with ready-made antibodies (e.g. against viper venoms, scorpion, after infection with tetanus bacilli).

The cells of the immune system protect not only against external pathogens (e.g. bacteria, viruses, toxins), but also internal ones, such as cancer cells. They come into direct contact with them and destroy them without the participation of antibodies. This protects us from the development of cancer.

Unfortunately, they also treat the cells of transplanted organs, such as the kidneys, as foreign cells of the immune system. In the case of transplants, such action of lymphocytes is fatal. T lymphocytes destroy the cells of the transplanted organ and the transplant, which was supposed to save life, is rejected by the body. Therefore, the attempts of T lymphocytes are inhibited by administering high doses of specialized drugs to transplant patients.

Worth knowing

Immunity changes with age

We get innate immunity from our mother as a dowry. During pregnancy, antibodies pass from her body through the placenta, which protect the baby from disease for 6-9 months after birth. If she is breastfed, this immunity lasts longer. But after the first year of life, the period of self-development begins. The immune system begins to produce antibodies to fight pathogenic microorganisms. The body remembers their antigens, which, when the same germs attack again, stimulate the very rapid production of antibodies that neutralize the enemy. Thus, the immune system of the littlethe child gradually matures and at the age of 3-4 years it reaches the proper immune capacity (it becomes fully mature when we are 18-20 years old). With age, immunity decreases. Probably because as the body ages, the thymus, in which T lymphocytes mature (B lymphocytes mature in the intestines or lymph nodes), shrinks and disappears. Gradually, its tasks are taken over by the bone marrow and lymph nodes. That is why children and seniors are most prone to disease.

Immune disorders - weakened immune system

Immunity depends on genes, daily habits, and nutrition. We have no influence on what we inherited from our ancestors. But a lot depends on ourselves. The most common causes of immunodeficiency are:

  • overuse of antibiotics - we do not have time for treatment, so when a banal cold takes us, we eagerly reach for a strong drug to quickly get us back on our feet. Meanwhile, most infections of the upper respiratory tract are caused by viruses, so an antibiotic will not help because it only fights bacteria. In addition, it weakens the body and makes it resistant to the drug. As a result, when it is really needed, then it stops working;

The first symptom of a weakened immune system is susceptibility to infections. So if you have a frequent cold, have sore throats or have recurring cold sores, it's a sign that your security system is failing.

  • bad diet - we eat too little vegetables and fruits, too much fat and processed foods. Therefore, we do not provide the body with the necessary amount of vitamins and minerals that protect us against diseases;
  • sedentary lifestyle - we move too little, drink hectoliters of coffee;
  • stress - we live in chronic stress, we don't have time to rest and truly relax. Meanwhile, scientists warn that 80 percent. stress diseases are the result of a weakened immune system;
  • sterile conditions - we raise children in sterile conditions, so they do not train their immunity;
  • detergents and antiseptics - irritate the epidermis and destroy the natural bacterial flora, which stimulates the immune system and prevents the growth of pathogenic bacteria;
  • exhaust fumes, nicotine smoke, air conditioning and dry air that damage the mucous membranes. All this makes it easier for germs to enter the body.

Immune disorders - overactive immune system

The immune system may also be overactive for unknown reasons. He then recognizes that not only viruses or bacteria, but all cells, including those of an organ, are dangerous to the body. It starts without delayproduction of antibodies intended to destroy them. In such a situation, many autoimmune diseases develop. For example, when the body destroys thyroid cells, it can develop Graves' disease or Hashimoto's disease. If the body considers the pancreas to be an enemy, it may develop insulin-dependent diabetes. When the immune system attacks the bone marrow, thymus, spleen, or lymph nodes, cancer can develop, including thymoma, Hodgkin's disease, and chronic lymphocytic leukemia. Other examples of autoimmune diseases (about 80 in total) are:

  • rheumatoid arthritis
  • Ankylosing Arthritis (AS)
  • lupus
  • vitiligo
  • multiple sclerosis.

Another example of an overactive immune system is allergies. It goes crazy, recognizing the enemy in neutral substances, e.g. pollen. When they enter the body, the defense mechanism starts, causing unpleasant symptoms of allergy, including runny nose, tearing, shortness of breath.

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Immune system