Basics of Immunity: How the Human Body Works

3 min


Immunity is a very famed word. People across the globe have a clear cut idea and caution about immunity.

But biologically speaking immunity is nothing but having resistance and defense against infections. There is a separate branch of biology called “Immunology” Which mainly concerns the immunity of humans.

Immunity is the word meant to get resistance from infections. Resistance to infections is done by many physical and chemical barriers. Various cells, organs, and even a whole system are meant to ensure high-grade immunity. Immunity is a special characteristic of animals especially vertebrates.

As said earlier immunity to organisms was bought by physical barriers such as mucous secretions in nasal and genital spaces, ciliary movements in cells, sweat and tear secretions, etc. It is very primitive than the Chemical barrier since the chemical barrier Includes some chemical formation.

Chemical Barrier

It includes the presence of “Lysozyme “ which is an enzyme. This kills a wide variety of Bacteria by digesting their cell wall. Besides that, the secretion of the antibody is very important.

It is specific since the antibody of one disease can’t cure another. The surface of the pathogen (Organism which causes disease) contains specific biomolecules like proteins, sugars, etc… Which triggers the immune cells to produce a substance and react with it.

The substance which was produced by immune cells to nullify the antigens is called “Antibody”. These antibodies are very specific. Since different antigens trigger the production of different types of antibodies. The antibody of one organism won’t react to another.

Besides this other major activity of the immune system (Combination of many organs to process immunization), is to identify and remove cancerous cells from the human body.

Immunity and Auto Allergy

When the components of the immune system attack the organism’s own cells and tissues, it leads to a medical condition called “Auto allergy”. It is also known as autoimmune diseases.

Self-antigens (Substances of the organism’s own cells that provoke immunity) are nullified by the immune system. This may lead to total destruction of tissue.

Example:-  Pernicious anemia, Rheumatoid arthritis, Type-1 Diabetes, Grave’s disease – Thyrotoxicosis, Myasthenia gravis, etc….

Causes for a Self Substance to become an Antigen

Some self substances remain hidden for a prolonged time and become naked at a part. Some antigens present in the eye lens are called lens antigens.

They are covered by the immune system since the human eye lens lack blood supply. Since blood is a primary path to immune cells, it remains hidden. On occasions like eye injury, cataract surgery these antigens become naked and they are considered as foreign particles and are severely attacked by immune cells.

How your Body Immunity Destroys Sperms?

Similarly, sperms are produced for males only after puberty, and those sperm cells are maintained void from immune cells. On the occasion of the disease mumps, it severely damages the parts like seminiferous tubules which are for storage and transportation purpose of sperms, these sperms will be in the sight of immune cells. Since for the first time after birth, they are visualizing sperms. So no longer they are native cells and those sperms are destroyed by the immune system.

How Your Immunity can Turn Against You?

Sometimes some physical and chemical agents like irradiation, drugs may cause alternation in the surface of the self cells which may make the immune cells faulty. For example, In the condition of dermatitis, anemia, leukopenia, etc… these are called Neoantigens.

The structure of self-antigens resembles foreign antigens, so the immune mechanism may be confused. Sometimes autoimmune diseases may arise due to a lack of tolerance of the immune system to specific self-antigens.

Based on the type of affected part autoimmune diseases are classified as

1) Haemolytic – Affecting only blood.

2) Specialized – Affecting only a particular part or organ.

3) Generalized – Affecting many organs or all over the body.

These diseases are commonly controlled by supplying immunosuppressive drugs which reduce the activity of the immune system.

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Narasimman S

I'm pursuing a UG Microbiology course. I'm aspiring to be a good science student. Spend my leisure time doing garden works.


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