The immune system is the body's means of preventing or limiting infection. Without it, the body would not be able to withstand bacteria, viruses, parasites, etc. attacks.
The immune system is made up of a vast network of cells, organs, proteins and tissues throughout the body.
A fully functional immune system can distinguish healthy tissue from unwanted substances. If it detects an unwanted substance, it will then trigger an immune response, a complex attack to protect the body from invaders. The immune system also recognizes and removes dead and damaged cells.
But the immune system doesn't always get it right. Sometimes, for example, it cannot fight effectively because the person has medical conditions or needs certain medications that affect the functioning of the system.
In autoimmune diseases and allergies, the immune system mistakenly perceives healthy tissue as unhealthy. In this case, an unnecessary attack begins, which causes uncomfortable and sometimes dangerous symptoms.
We will cover the main features of the immune system and how they protect the body from pathogens and other invaders. We will also look at problems that may arise with the immune system.
Immune system
The immune system is made up of various parts, including:
- white blood cells (leukocytes)
- the spleen
- bone marrow
- the lymphatic system
- thymus gland
- tonsils, adenoids
White blood cells circulate in the blood and lymphatic vessels.
The lymphatic system forms a network similar to blood vessels. It has a substance called lymph instead of blood. Lymph is the fluid that carries immune system cells to areas that need them.
White blood cells are constantly looking for pathogens. When they find them, they begin to multiply and send signals to other cell types to do the same.
The body stores white blood cells in different places called lymphoid organs.
These include:
- The thymus gland: a gland behind the breastbone where white blood cells known as lymphocytes mature
- Spleen: An organ in the upper left corner of the abdomen where immune cells gather and work.
- Bone marrow: Soft tissues in the center of bones that produce red and white blood cells
- Lymph nodes: These are small, bean-shaped glands throughout the body, especially in the neck, armpits, groin, and abdomen. They connect through lymphatic vessels. Immune cells gather in the lymph nodes and react when antigens are present. This can cause swelling.
- Tonsils, adenoids: It is the gateway for pathogens to enter the body, so lymphoid tissue is also present.
How the immune response works
To function effectively, the immune system must be able to distinguish between healthy cells and unhealthy cells and tissues. It does this by recognizing signals called DAMPS - danger-associated molecular patterns.
Cell damage can be for many reasons, including:
- infectious agents such as bacteria or viruses
- toxins such as bites or stings
- non-infectious physical damage such as burns
- genetic cell problem, as happens with cancer
An antigen is any substance that can trigger an immune response.
In most cases, the antigen is a bacterium, fungus, virus, toxin, or foreign body. But it can also be a cell that is damaged or dead.
The immune system detects pathogen-associated molecular patterns - PAMPs - in the antigen. In this way, various parts of the system recognize the antigen as an invader and launch an attack.
Types of white blood cells
Phagocytes
These cells surround the reliable source and absorb the pathogens and break them down, effectively eating them.
There are several types:
- Neutrophils: They are also known as granulocytes and provide an early response to inflammation. They kill pathogens, but they also die because of it.
- Macrophages: They are cleared after the response. They remove pathogens, dead neutrophils, and other debris.
Dendritic cells: This activates the immune response and helps to engulf microbes and other invaders.
- Monocytes: They can differentiate into dendritic cells and macrophages as needed.
Mast cells: They trigger an immune response when they detect an antigen.
- Mast cells: They trigger an immune response when they encounter an antigen.
Lymphocytes
Lymphocytes help the body remember previous invaders and recognize them if they come back to attack.
Lymphocytes begin their life in the bone marrow. Some remain in the bone marrow and develop into B lymphocytes (B cells); others travel to the thymus gland and become T lymphocytes (T cells). These two cell types have different roles.
B lymphocytes produce antibodies and help alert T lymphocytes. T lymphocytes destroy damaged cells in the body and give a signal to leukocytes.
Natural killer (NK) cells are also lymphocytes. NK cells recognize and destroy cells that contain the virus.
The role of B lymphocytes
When B lymphocytes spot an antigen (antibody generator), they begin to secrete antibodies. Antibodies are special proteins that bind to specific antigens.
Each B cell produces one specific antibody. For example, one may produce an antibody against the bacteria that causes pneumonia, while another may recognize a cold virus.
Antibodies are part of a large family of chemicals called immunoglobulins that play many roles in the immune response:
- Immunoglobulin G (IgG) marks microbes so other cells can recognize and fight them
- IgM specializes in killing bacteria
- IgA collects in fluids such as tears and saliva, where it protects the gateway to the body
- IgE protects against parasites and plays a role in allergies
- IgD remains bound to B lymphocytes, helping them initiate an immune response
Antibodies attach to the antigen but do not kill it - they only mark death. Killing is the job of other cells, such as phagocytes.
The role of T lymphocytes
There are different types of T lymphocytes or T cells.
Helper T cells (Th cells) coordinate the immune response. Some communicate with other cells, and some stimulate B cells to produce more antibodies. Others attract more T cells or cell-eating phagocytes.
Killer T cells (cytotoxic T lymphocytes) attack other cells. They are especially useful in fighting viruses. They work by recognizing small parts of the virus on the outside of infected cells and destroying the infected cells.
The role of natural killer cells
They contain granules with powerful chemicals. They are useful in attacking many types of unwanted cells.
In blood tests, we often get results that have specified limits. But in order to better understand the results of blood tests, you can find out: Explanation of blood test results
Immunity
In general, the immune system becomes stronger when exposed to different pathogens. By adulthood, most people have been exposed to various pathogens and have acquired more immunity.
When the body produces an antibody, it stores a copy so that when the same antigen comes up again, the body can deal with it more quickly.
Some diseases, such as measles, can be serious if they occur, so experts recommend vaccination. If a person has the measles vaccine, it is unlikely that they will get the disease.
If an unvaccinated person gets measles once, it is also rare to get it again. In both cases, the body stores the measles antibody. The antibody is ready to destroy the virus the next time it appears. This is called immunity.
Humans have three types of immunity:
- Congenital
- Adaptable
- Passive
Innate immunity
Humans are born with a certain level of immunity that will attack invaders from day one.
This innate immunity includes our body's outer barriers—the first line of defense against pathogens—such as the skin and the linings of the throat and gut.
This response is general and non-specific.
If pathogens manage to bypass the innate immune system, macrophages will attack them. Macrophages will also produce substances called cytokines that increase the inflammatory response.
Adaptive (acquired) immunity
Human defense against pathogens evolves as we go through life.
As a result of vaccinations and exposure to various diseases, the body produces many antibodies against different pathogens. Doctors sometimes refer to this as immunological memory, because the immune system remembers previous enemies.
Passive immunity
This is a temporary type of immunity that you get from another person.
For example, a newborn receives antibodies from the mother through the placenta before birth and breast milk after birth.
This passive immunity protects the baby from some infections at an early age.
Vaccines
Immunizations change the body in some way so that it can respond effectively to various diseases.
The most common method is to introduce antigens or weakened pathogens into a person so that the person produces antibodies and does not get sick.
Because the body retains copies of the antibodies, it has protection should the threat arise again later in life.
Doctors may recommend vaccination against:
- COVID-19
- The flu
- Redheads
- Poliomyelitis
- Chickenpox
- Shingles
- Measles
- Little pigs
- Meningitis
- Hepatitis
- Hib (Haemophilus influenzae type B)
- Diphtheria
- tetanus
- Other diseases such as yellow fever and typhoid, depending on where the person lives or travels
Immune disorders
There are many ways the immune system can go wrong. The types of immune disorders fall into three categories:
Immunodeficiency
It occurs when one or more parts of the immune system do not work.
Immunodeficiency can be caused by:
- a condition that a person is born with known as primary immunodeficiency
- changes over time, such as old age
- diseases that affect the immune system, such as HIV, malnutrition, obesity or high alcohol consumption;
- medical treatment such as chemotherapy, medicines to treat an autoimmune condition or medicines to prevent the body from rejecting a transplant.
These conditions can increase a person's risk of becoming ill or experiencing severe symptoms, as the COVID-19 pandemic has shown.
Autoimmunity
In autoimmune conditions, the immune system misreacts and targets healthy cells instead of bad cells. The immune system cannot distinguish between healthy and unhealthy cells and tissues.
It usually occurs in one part of the body, such as the pancreas. Destruction of beta cells in the pancreas means that the body cannot produce a reliable source of insulin. This is how type 1 diabetes occurs.
Other autoimmune diseases include:
- Celiac disease
- Rheumatoid arthritis
- Graves' disease
Hypersensitivity
In hypersensitivity, the immune system reacts excessively or inappropriately. It attacks everyday materials like dust as if they were pathogens.
This happens with:
- asthma
- food allergies and sensitivities
- atopic eczema
A severe reaction can lead to anaphylactic shock, when the body reacts to an allergen so strongly that it can be life-threatening.
Frequently asked questions
Here are some answers to questions people often ask about immunity.
How to improve immunity?
Tips for strengthening immunity:
- a high-quality and varied daily diet that includes fresh fruits and vegetables.
- limit the intake of added salts, fats, sugars and alcohol
- exercise regularly
- Get enough and quality sleep
- maintain a proper body weight
- avoid smoking
What vitamins are best for immunity
Various vitamins and minerals ("micronutrients" and "macronutrients") are essential for a healthy immune system.
It is important to have high-quality vitamins from reliable manufacturers. Vitamins recommended by specialists can be found:
More information can be found here For the immune system
What are the types of immunity?
Innate immunity, which people are born with, includes the skin, mucous membranes, and various components of the immune system.
Acquired immunity comes from exposure to vaccines and diseases. This allows the body to produce antigens that can help it fight the same disease a second time.
Passive immunity is protection provided by another person, such as when a newborn baby is temporarily protected from certain diseases because its mother has immunity.
Why is immunity important?
Immunity protects the body from bacteria, viruses and other pathogens that can cause life-threatening diseases.
It's important
The immune system is a complex system that is vital for survival. When the body encounters harmful invaders, such as a virus or a splinter in the finger, it launches an attack to destroy the pathogens.1
People are born with certain types of immunity, but exposure to diseases and vaccinations can also help strengthen the body's defenses.
Some people have a weakened immune system due to health problems or medication. A doctor can advise on how to protect a person's health while living with a weakened immune system.
Ways to boost immunity include dietary and exercise choices, avoiding alcohol and smoking, and getting the right vaccinations.
It is important to rememberthat everyone's health is individual and there is no common recipe for everyone!
So, if you want to know what nutrients your body might be lacking right now, health professionals recommend a guide – "Your Day".
- In time, pay attention to the signals sent by your well-being
- Replenish the body with natural minerals, vitamins and nutrients necessary for health.
- Enjoy energy and good mood everyday!
