Fighting fiercely against tiny enemies - the story of the immune system

Did you know that our immune system consists of two subsystems? One is born, and the other is acquired during our lives. Both together fight invaders (bacteria, viruses, etc.) as much as they can. So why do we need vaccines? Because even these two are not always enough to fight all the troubles

Written by: Zvi Atzmon, of: Young Galileo, issue 198 July 2020

We see our body first of all as belonging to us, but many tiny creatures see it as a wonderful place to live and reproduce at our expense. Our body can provide them with all their needs: food, water, the mechanisms they need, a comfortable temperature.

These are multitudes of creatures that are around us: in the air, on our skin, in the water and in the food. This refers to bacteria, single-celled parasites, viruses, tiny fungi and more. These disease agents are called pathogens in medical language.

You kicked out the exploiters

Since all of these try to attack our body and take advantage of it, we need an effective defense system. This is the job of the immune system. The immune system manages in most cases to successfully repel all these exploiters. If it does not manage to repel them completely, we are sick with some kind of infectious disease.

It is important to clarify the difference between the immune system and the vaccine component that we receive in the form of an injection, drops or spray. Thanks to the body's natural immune system, vaccine components that are injected into our bodies help us to get vaccinated - to be protected against infectious diseases.

Two subsystems

Our immune system consists of two subsystems: one with which we are born, and the other is acquired during our lifetime - for example, after we have contracted an infectious disease or received a vaccine component. Both systems include both immune cells and vaccine materials. They work together, in close cooperation.

The innate immune system is the body's first line of defense against disease agents; The acquired immune system is necessary for the immune response to be effective. In order to act, the immune system distinguishes between components of the body itself and between foreign factors that have invaded our body.

against everything "foreign"

Each of the components of the innate immune system works against a wide variety of disease agents. It does not distinguish between different causes of disease, but acts against what is "foreign", which is not part of our body. The innate immune system includes an enzyme that breaks down the walls of bacteria, proteins that interfere with various disease agents, other proteins that "mark" disease agents as destined for elimination by killer cells, other proteins that create holes in bacterial membranes, and white blood cells that swallow and digest various disease agents.

The acquired immune system is very sophisticated. Each of its components acts specifically against one specific disease agent. It includes two types of white blood cells - B lymphocytes and T lymphocytes, as well as a very large group of proteins called gamma globulins, which includes the antibodies. The antibodies are produced by B lymphocytes. A foreign factor (disease factor) that stimulates the creation of antibodies is called an antigen.

the immune memory

The first time the acquired immune system is exposed to a certain antigen it needs time to react. At the same time the innate system reacts quickly, but it is not specific; When the purchased system is up and running, it is extremely efficient. Cells specific to that antigen multiply in it, and some of these cells produce antibodies against that disease agent only.

After the acquired system is exposed to a certain antigen, memory cells are formed, and the next time it is exposed to the same antigen - it will respond efficiently and quickly. Thanks to immune memory, we have long-term immunity to many diseases that we have contracted in the past, sometimes for life.

Immune memory is the basis for the action of vaccines (immune components) - thanks to them our body is exposed to weakened or killed disease agents, memory cells are formed in the immune system, and if we are exposed to such a violent disease agent in the future, we will be vaccinated and will not get sick.

When there is no vaccine

A serious problem exists regarding new viruses that have appeared, against which there are still no vaccine components, as in the case of Covid-19, which caused the corona epidemic. There is also a problem with disease agents that are constantly changing, so the immune memory is not valid for them. This is the case with the flu viruses that change every year, and so with the malaria agent (which is neither a virus nor a bacterium, but a single-celled parasite) against which there is still no effective vaccine.

A tolerable vaccine does not cause the appearance of memory cells, but is an injection of antibodies created in the body of someone who has already been vaccinated (an animal or a person). One of the possible ways to help Covid-19 patients is an injection of the group of proteins that includes the antibodies extracted from the blood of those who recover from the disease, and therefore people who have recovered from Corona are asked to donate blood plasma.

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