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Immune System And Immunology

Immunology can be defined as the study of the immune system and the cell-mediated and humoral aspects of the immunity and the immune responses. Immunology is a branch of biology that is involved in the study of the immune system, the biological processes of the immune system, components of the immune system, the types of the immune system, its disorders, and the functioning of the immune system to name a few aspects about immunology.

The immune system present in the body acts as a defense system to protect our body cells, tissues, and organs from the dangerous infections invading through the various lines of defence. The immune system functions as a physical barrier to prevent the entry of the disease-causing pathogens that include the harmful microorganisms and the other infectious microbes.

In cases, when our immune system stops functioning or functions poorly, this results in infectious diseases like fever, flu, allergies, and can also lead to life-threatening diseases like cancer, etc.  

Immune System  

The human immune system comprises the different types of cells and molecules that are responsible for protecting our body against pathogens. The pathogens are the parasites, fungi, viruses, bacteria, and haptens, etc. that enter our body and cause us to fall sick. Haptens are the molecules that can cause an immune system to respond when it comes to the contact of a protein. All of these cells and molecules are distributed in all of the tissues and the cells of the body as well as the lymphoid organs that are responsible for eliminating the microbial infectious diseases to prevent the growth of tumors and also to initiate the process of repairing the damaged tissues. The tissues and the organs involved in the immune system act as the security forces in which the cells act as the security guards, and the molecules act as bullets that are used as a communication system to overcome the attack of the pathogens and to protect our bodies from the diseases.

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Types of Immune System

The immune system present in humans is of two types, and they can be classified on the basis of the resistance and the power to fight against the harmful invading agents. They are the innate immune system and the adaptive immune system.

  • Innate Immune System: The innate immune system comprises the cells and the proteins that are there in the body and are always ready to fight against the microbes in the infection area. The innate immune system is present from the time we are born, and the main elements in the innate immune system include natural killer (NK) cells, circulating plasma proteins, dendritic cells, physical epithelial barriers, and the phagocytic leukocytes.

  • Adaptive Immune System: This immune system is required to fight against the pathogens that control the innate immune system defences. Since this immune system is acquired by us during the course of our lifetime, it is also referred to as the Acquired Immune System. The components in the Adaptive Immune System are generally inactive, but they get activated when these components adjust themselves according to the presence of the infectious agents by proliferating and developing a potent mechanism that fights to eliminate the microbes. The two types of adaptive responses are humoral immunity moderated by the antibodies that are developed by the B lymphocytes and the cell-mediated immunity and are moderated by the T lymphocytes.

Immunology and Diseases

Generally, the diseases occur due to the fundamental defects in the immune system. When the bodies are exposed to the pathogens, the immune system gets challenged to evoke the responses that, in lieu of protecting the cells and tissues, damage them. The immunodeficiency diseases are known to increase the risk of the infections, and the tumours that are caused by gene mutations, viruses like HIV and malnutrition.

Symptoms of Immune Dysfunction     

The symptoms of the weaker immune systems and the immune dysfunction are as follows: -

  • Rhinitis or a constant runny nose

  • Bowel disorders

  • Painful joints and muscles

  • Allergies and Asthma

  • Frequent colds and flu

  • Herpes (cold sore) outbreak

  • Autoimmune disorders

  • Candida overgrowth

  • HPV and abnormal PAP smears

  • Parasite infections

  • Psoriasis, eczema, hives, or rashes

Immunological Techniques

The immune system structure and its functions can be studied through an experimental method and the different techniques that are used for the same include: -


  • Isolation and Purification of Antibodies


  • Immunohistochemistry

  • Generation of Antibodies

  • Immune cell isolation

  • Immuno-blotting and precipitation

  • Immuno-histo-chemistry

Applications of Immunology

Immunology can be used in several disciplines like medicine, oncology, virology, organ transplantation, psychiatric disorders, parasitology, rheumatic diseases, and dermatology, to name a few. The immunology in the transplantation process generally deals with the process of transplantation from the donor to the recipient. 

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FAQs on Immunology

1. What Is An Immunization? Which Cell Is Involved In Cell-mediated Immunity? What Is An Antigen?

Immunization is defined as the process of activating the person’s immune system by the administration of a vaccine. This is important as it helps the individuals to protect themselves against the dreadful diseases and infections. In the absence of an immune system or a weakened immune system, the individual is highly susceptible to life-threatening ailments. 

T cells are involved in cell-mediated immunity.  An antigen is a type of protein that initiates the production of an antibody and causes an immune response. 

2. What Is The Immune System? How Many Types Of Antigens And Antibodies Are Found In The Human Body?

An immune system can be defined as a defence mechanism that is present in the human body that helps the body to protect and fight against the disease-causing pathogens and germs. Proper functioning of the immune system is essential for any living being as it offers protection against infections and ailments. When it comes to the antigens and antibodies found in the human body, there are a total of two types of antigens and five types of antibodies that are present in the human body.

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