ReviewLaza » Health & Fitness » Immune System: How Does The Immune System Work

Immune System: How Does The Immune System Work

Raina Rahul Agarwal 14 Sep, 2021 Health & Fitness 8 Comments

Immune System

Our Immune System 

The immune system defends our body against infection means it protects our body against outside invaders like bacteria, fungi, viruses, and toxins (chemicals produced by microbes). The immune system is a network of biological processes and protects our body from diseases.

Without the Immune system, we can not fight diseases, we can not fight with foreign matter which enters inside our body without immune system we can not protect our body with harmful changes which occur inside our body, it keeps us healthy

It is made up of different organs, cells, and proteins that work together, it includes white blood cells, and tissues of the lymph system such as the thymus spleen, tonsils, lymph nodes, lymph vessels, and bone marrow.

How does the Immune System Work

Parts Of Immune System

  1. Innate Immunity
  2. Acquired or Adaptive Immunity are two main parts of the Immune System

Innate Immune System

The innate immunity system is inherited and is active from the moment when a baby is born i.e every person is born with innate immunity. When this system recognizes the invader it goes into action immediately. It mainly consists of physical barriers on or inside the body e.g. skin works as a barrier to block germs from entering the body. The main feature of the Innate Immune System is to respond quickly, which can lead to inflammation and fever. Most fights using immune cells such as natural killer cells and phagocytes (Eating Cells).

Acquired (Learned) Immune System

The acquired or adaptive immune system develops throughout our lives. It makes antibody and specifically fights against germs. When our immune system is exposed to a new germ for the first time, these antibodies are developed by cells B lymphocytes after the body has been exposed to the invader. This immune system will recognize the invader and defend against it.

“Immunisation trains our body to develop antibodies to protect from harmful diseases.”

Main players of the Immune System

White Blood Cells

One of the most important players of the immune system is white blood cells also called “Leukocytes”. There are two types of leukocytes- Phagocytes-Neutrophils, Monocytes, Macrophages, Mast Cells & Lymphocytes. B Lymphocytes create antibodies and alerts T Lymphocytes to kill the pathogens.

Antibodies are a large family of chemicals called Immunoglobin which plays many roles in the immune response-

Immunoglobin G (IgG)-marks microbes so other cells can recognize and deal with them.

IgM- Kill bacteria

Ig A- Secretes fluids such as tears & Saliva where it protects as a barrier.

Our immune system

IgE- Protects against the parasite and also challenges the allergen.

IgD- Bound to B Lymphocyte and helps them to start the immune response.

Other white blood cells are-

Thymus, Spleen, Bone Marrow, Lymph Nodes

How The Immune System Is Activated

An Antigen can be a microbe such as a virus, bacteria, toxin, a chemical that comes from outside to inside our body. If the body comes into contact with an antigen it stores information about the antigen and how to fight against it.

If antigen enters inside our body B cells recognize them. B cells are triggered to make antibodies ( also called immunoglobin). These proteins lock onto specific antigens ( Lock key configuration). Each B Cells makes one specific antibody e.g. one might make an antibody against bacteria that cause pneumonia, and another antibody may recognize the common cold virus.

Once antibodies are made, they usually stay in our body in case we have to fight the same germ again. That’s why when someone gets sick with a disease, like chickenpox, usually would not get sick from it again. This is how the human body develops immunity ( Acquired ) to a particular disease.

Everyone’s immune system is different, it becomes stronger during adulthood, as time passes we have been exposed to more pathogen and develops more immunity. That’s why adults get less sick than children.

Frequently Asked Question

Question- What is Antigen?
Answer- A substance that enters the body and can cause diseases and another harmful effect is called “Antigen”.

Question- What is Allergy?
Answer- Allergy occurs when a person reacts to substances in an environment that are harmless to most people. These substances are known as Allergen and are found in dust mites, pets pollen, insects, ticks, molds, foods, and some medications.

Question- What are the parts of the immune system?
Answer- Immune System has many parts, it includes-
Skin, which can help prevent germs from getting into the body.

  • Mucous Membrane is the moist inner lining of some organs and body cavities.
  • White Blood Cells fight germs.
  • Organ and tissue of the lymph system, such as thymus, spleen, tonsils and lymph nodes, lymph vessels, and bone marrow. They produce, store and carry white blood cells.


Our health is depended upon our immune system. If our immune system is good then our health will also be good. For a Good immune system, we have to have healthy foods in our diet and we should do exercise.


Any information found on this website is for general information and educational purpose only. The information is not intended or otherwise implied to be medical advice.


Thank you to visit ReviewLaza.

Please read some more informative articles on our site Nipah Virus, RT-PCR




author avatar
Raina Rahul Agarwal
My name is Raina Agarwal, and I am a seasoned content writer with three years of experience in the field. Holding a master's degree in microbiology. I have also garnered valuable experience as a microbiologist, with a career spanning over a decade since 2011. My diverse professional background enables me to offer unique insights and perspectives in my content creation endeavours.

Raina Rahul Agarwal

A Non-Medical Scientist, BSL-2 Lab, Mirzapur

8 Comments on 'Immune System: How Does The Immune System Work'

Leave a Comment

  • Name
    URL: (Optional)