Immunology Definition, Branches and Career

Table of Contents

Immunology Definition

Immunology is a branch of biology that deals with the study of the immune system in animals and humans. It is simply a scientific study of both the structural and functional state of the immune system.

Branches of immunology

As a branch of biology that is concerned with the study of the immune system, it is therefore categorized into sub-disciplines to help specialize in the field. These sub-divisions include;

Clinical Immunology

This is the branch of immunology that deals with the study of diseases caused by an immune system dysfunction or disorder. Also, it involves the study of the role of the immune system response to other system’s diseases. Again, it covers the study of the process of the immune system destroying allografts (transplant).

Ecoimmunology and Behavioral Immunology

This is a branch of immunology that studies the relationship between the immune system of an organism and its social, biotic, and abiotic environment. It involves the use of practices considered to be non-immunological such as pathogen avoidance, symbiont-mediated defenses, and self-medication. Furthermore, behavioral immunology deals with psychological pathogen avoidance. For example, being disgusted by the smell of vomit, of someone who has been infected by the pathogen.

Developmental immunology

This aspect of immunology deals with the development of the immune system from birth to adulthood. The ability of the body to react to antigens is influenced by a person’s age, antigen type, maternal factors, and the environment in which the antigen is presented.

Developmental immunology studies how the immune system of a child develops; a child’s immune system begins to respond more strongly to glycoproteins between six and nine months after birth, but there is usually no noticeable improvement in their response to polysaccharides until they are at least one year old. This could explain why vaccination schedules have different time frames.

Molecular Immunology

This is the branch of immunology that studies the immune system at the molecular level. The study of the process of signaling and response is analyzed in this sub-division. Also, the activation of defense cells, as well as the structures and functions of the molecules that the cells secrete, such as receptor and mediator molecules. As a result of this field, a great understanding of the workings of the immune system has been obtained. Including the various ways to manipulate different aspects of the immune system, in order to improve its effectiveness against destructive disorders or diseases.

Cellular Immunology

This is the branch of immunology that studies the cells that are involved in the response of the immune system. It gives an in-depth review of the type of cells, their structure, and their functions. These cells are found in the tissues and organs of the body. Also, these cells include T and B cells. Also, a study of the point of production of the cells and their intending target are covered. It has also helped immunologists to classify these cells under their mode of reproduction and their functions. Therefore, making the whole process easy to comprehend.


This is the branch of immunology that bridges the gap between genetics, diseases, and the immune system. In essence, hereditary diseases and how they affect the immune system are studied. It gives a review on the history of hereditary diseases, and pre-existing disorders, that are genetically underlined. It is also an important branch of genetics that helps to provide treatment for autoimmune disorders, and how to prevent such disorders or diseases from transferring into the next generation.


This is the branch of immunology that is similar to molecular immunology. Hence, it is concerned with the study of the molecular mechanisms that are involved in immune system defense. It gives knowledge on protein as an antigen and the antibodies that bind to them. Also, these mechanisms are achieved through a number of techniques that are used to visualize the process of how the system works. For example, the enzyme/substrate reaction used to study the immune cell interaction with how they destroy invading organisms.


This branch of immunology focuses on the diverse approaches to the study and manipulation of various immune system mechanisms. These approaches might be biological, physical, or chemical.


This is the branch of immunology that deals with the effect or impact of toxins on the immune system. This branch looks at how cells are affected by chemicals (toxins), and how the immune system responds to these invasive chemicals.


This branch simply focuses on the response of the immune system to the various organisms in the body.

Diagnostic Immunology

This is a branch of immunology that focuses on how to diagnose an immune system disorder, by specifying the bond between antibodies and antigens. This can be done by conjugating antibodies specific to targeted antigens with an isotope or color-forming enzymes.


This is the branch of immunology that studies the use of immune system components, their antigens to treat disorders or diseases. This knowledge is regularly used to treat autoimmune diseases such as Crohn’s disease, allergies, and some type of cancer cells (breast cancer).

Cancer Immunology

This is the branch of immunology dedicated to cancer research, the reaction of the immune system to cancer cells, and ways to treat and cure cancer. Cancer as it is known is a disease that involves abnormal and uncontrolled cell growth and its ability to avoid immune destruction. It also involves the study of the use of monoclonal antibodies that finds and binds themselves to a target antigen. For instance, Herceptin is a monoclonal antibody used to treat breast and stomach cancer. Furthermore, it involves the creation or manufacturing of cancer vaccines like the HPV vaccine.

Reproductive Immunology

This branch of immunology focuses on the aspect of reproduction that involves fetus acceptance, fertility problems, recurrent miscarriages, premature deliveries, and pre-eclampsia. For example, the possibility of a mother and her child having a different immune system during the early stages of development can lead to the destruction of the fetus. Because the immune system of the mother sees the baby as a foreign invader, that is coming to attack thereby sending an early response to defend the mother.

Theoretical Immunology

Although immunology is mainly practical, it also has a branch that studies the theories before they are experimented and actualized. There have been several theories since the 19th century till date by scientists. Some of these theories are now used in treatment, understanding, and education. For example, the cellular theory states that” cells more precisely phagocytes are responsible for immune responses”. And on contrast, the theory of humor states that” active immune agents are soluble components (molecules) found in the organism’s humor rather than cells”. Furthermore, there have been recent theories such as the autopoietic, danger, discontinuity, and cognitive immune theories are being studied.

Veterinary Immunology

This is the branch of immunology that focuses on the study of animal diseases and their immune responses, in a bid to improving animal health. These animals like humans are affected by pathogenic microbes and they invade the body system. Sometimes their immune system does not function properly and they may also have immune system disorders. In this branch, we can also see the prevention of diseases that transfers across barriers from animals to humans and vice versa a term known as “zoonosis”. For instance, COVID19, swine flu, avian influenza, and malaria are known to affect humans from animals and insects.

Immunology Assays and Tests

These are tests conducted for the purpose of diagnosing a disorder, or for the purpose of learning more about the mechanism involved. Also, they are used to detect hormones, pigments, and microorganisms that play a role in immunology. In addition, these tests are used to understand the characteristics and identification of antibodies.

Examples of immunological tests
Agglutination test
For the purpose of identifying reactions between antibodies and antigens
Enzymes immune assays
Used in the identification of antibodies and antigens
Western blot test
Used in the identification of certain proteins
Complement fixation
Used for the purpose of identifying or testing the presence or absence of antibodies
Allergy test
Used for the identification and determination of allergens and also for the diagnosing of hypersensitivity to various molecules

Career in immunology

Immunology being very broad has many fields and it is a very good career choice. But before we dive into the careers, we must first answer the question of who is an immunologist and what they do.

Who is an immunologist?

An immunologist is someone that studies the immune system of either animals or humans. For example, they study the diseases and disorders that affect the immune system, the environmental factors that affect immune system function and why disorders and diseases develop, and the required or necessary treatment.

What do immunologists do?

An immunologist’s primary responsibility is to study, diagnose, treat, and help prevent immune system disorders. For example, lupus, asthma, and allergies. Some of them are specialists in theoretical immunology, where they postulate and hypothesize theories that can help researchers. Some others are researchers in the laboratory where they bid or try to understand how the immune system works. While there are those who choose the path of clinical immunology, helping in diagnosing and treatment of patients with immune system disorder and diseases. Still on the clinical department, are those that develop vaccines and those that develop new methods of treatment, and there are specialists in organ transfer rejection.

Also, there are those called environmental immunologist that specializes in the study of how the natural and chemical substances found in the environment, affect the immune system response. They also diagnose and treat wild animals by conducting researches and developing cures to help boost their immune system.

Possible career choice

  • Academic researcher
  • Teacher/lecturer
  • Laboratory research specialist
  • Pharmaceutical and biotechnological research specialist
  • Clinicians
  • Veterinary immunologist
  • Research assistant
  • Therapist
  • Consultant
  • Health care worker

What is the average salary of an immunologist?

The average salary of an immunologist ranges from $187,200 – $ 200,890 per annum.

How to become an Immunologist

Becoming an immunologist and specialist is no easy task. It requires work and time because of the extensive training and education involved. Thus getting a bachelor’s degree is only the first step, as medical school is a prerequisite for those who want to venture or specialize in clinical immunology. Also, a Ph.D. is required to become a specialist in immunology. In addition, offering a major in biology can also aid in your quest to becoming a qualified immunologist. And as for the students pursuing a career in environmental immunology, they are taught basic immunology, toxicology, disease pathways, and research methods.

So, there you have it all in a brief, so happy hunting in your new career choice!

Importance of Immunology

The following points are some of the importance of immunology and why it should be considered.

  1.  Aids in the development and creation of new vaccines
  2. It has made organ transplanting safer
  3.  Helped in the identification and cross-matching of blood groups and antibodies before transfusion
  4. It has helped in the discovery, diagnosis, and treatment of new and various immune system diseases and disorders.
  5. Has helped in the development of new research techniques and tools. Especially in the fight against cancer and other autoimmune disorders.


Why do I want to study immunology?

Immunology research is essential for human and animal health and survival. Immunologists are working on new treatments for some of the world’s most serious diseases, including infectious diseases (like influenza and Ebola), autoimmune diseases (like type 1 diabetes), and cancers.

What is the basic principle of immunology and its application?

Immune health is based on four fundamental principles:

  1. The ability to detect and combat infection
  2. The ability to recognize a host’s own cells as “self,” thus defending them against attack.
  3. A recollection of prior foreign infections
  4. The ability to control the response after the pathogen is eliminated.

What are the benefits of immunology?

Immunology is an important branch of medical and biological sciences that studies the immune system. Through various lines of defense, the immune system protects us from infection. Diseases such as autoimmunity, allergies, and cancer can occur when the immune system is not functioning properly.

Where can I study immunology?

  • The best immunology universities in the world are listed below.
  • Harvard University
  • The University of California, San Francisco (UCSF)
  • The Massachusetts Institute of Technology
  • Johns Hopkins University
  • Louis’ Washington University
  • The University of Washington
  • Stanford University
  • The University of Pennsylvania

What is the role of an immunologist?

Immunology is the branch of medicine that deals with the immune system, which is the body’s defense system. Immunologists research how the immune system works and treat patients who have immune system problems.

What do you need to become an immunologist?

In becoming an immunologist, one must have a Ph. D. or a certified medical doctor, as well as at least two to three years of training in an accredited program and pass the American Board of Allergy and Immunology examination.

Is it hard to become an immunologist?

To become an immunologist, you’ll need a lot of education and experience. A bachelor’s degree is just the beginning. Medical school and an M.D. are required for clinical positions that involve working with patients. Many colleges and universities offer pre-med programs that lead to a bachelor’s degree. Following medical school, a residency is required.

How many years does it take to become an immunologist?

To earn a Doctor of Medicine, a student must first earn a bachelor’s degree, preferably in biology or chemistry, and then complete four years of medical school (M.D.). The M.D. graduate then completes up to seven years of internal medicine residency, followed by at least a two-year immunology fellowship.

What happens when you go to an immunologist?

Allergists/immunologists diagnose, treat, and manage allergies, asthma, and immunodeficiency diseases, among other immunologic conditions. Many allergists and immunologists combine clinical experience with academic research to better understand how the immune system works and to test new treatments.

What is immunologic disease?

Allergies, asthma, autoimmune diseases, autoinflammatory syndromes, and immunological deficiency syndromes are examples of immunological disorders caused by immune system dysfunction

What does immunological tolerance mean?

Tolerance is the ability to suppress an immune response to a specific antigen. The immune system, for example, is usually tolerant of self-antigens and does not attack the body’s own cells, tissues, or organs.

What is immunological defense?

Immunological defense refers to a higher organism’s ability to recognize and combat potentially harmful microorganisms such as viruses, bacteria, fungi, protozoa, and helminths using complex mechanisms involving soluble factors (Humoral Immunity) and immune-competent cells (Cellular Immunity).

What are the basics of immunology?

The study of the components that make up the innate and adaptive immune systems is known as fundamental or classical immunology. The first line of defense is innate immunity, which is non-specific. That is, regardless of how different potential pathogens are, the responses are the same.

How does immunological tolerance occur?

When the immune system is exposed to a foreign antigen, the antigen is either eliminated by the standard immune response (resistance) or the immune system adapts to the pathogen, resulting in immune tolerance. Inflammation causes pain, swelling, and tissue dysfunction.