Immunology

What is immunology?

Immunology is the study of the immune system and is a very important branch of medical and biological sciences. The immune system protects us from infection through several lines of defence. If the immune system is not working as it should, it can lead to diseases such as autoimmunity, allergy, and cancer. It is also now becoming clear that immune responses contribute to the development of many common disorders not traditionally thought of as immunologic, including metabolic, cardiovascular, and neurodegenerative diseases such as Alzheimer’s.

Why is immunology important?

From the pioneering work of Edward Jenner in the 18th century that would ultimately lead to vaccination in its modern form (an innovation that has probably saved more lives than any other medical advance) to the many scientific advances in the 19th and 20th centuries that would lead Through, among other things, safe organ transplantation, blood group identification, and the now ubiquitous use of monoclonal antibodies in science and health care, immunology has changed the face of modern medicine.

Immunology research continues to push the envelope in our understanding of how to treat important health problems, with ongoing research efforts in immunotherapy, autoimmune diseases, and vaccines for emerging pathogens such as Ebola. Improving our understanding of basic immunology is essential for clinical and commercial application and has facilitated the discovery of new diagnostics and treatments to manage a wide range of diseases. In addition to the above, along with the advancement of technology, immunological research has provided critically important research techniques and tools such as flow cytometry and antibody technology.

What is an immunologist?

An immunologist is a scientist and/or physician who specializes in immunology. Many immunologists work in a research-focused laboratory, either in academia or in private industry (for example, in the pharmaceutical industry). Other immunologists, “clinical immunologists,” are doctors who focus on the diagnosis and management of diseases of the immune system, such as autoimmune diseases and allergies.

The immune system

The immune system is a complex system of structures and processes that have evolved to protect us from disease. The molecular and cellular components make up the immune system. The function of these components is divided into nonspecific mechanisms, which are innate to an organism, and responsive responses, which are adaptive to specific pathogens. Fundamental or classical immunology involves the study of the components that make up the innate and adaptive immune system.

  • Innate immunity is the first line of defence and is not specific. That is, the responses are the same for all potential pathogens, however different they may be. Innate immunity includes physical barriers (eg, skin, saliva, etc.) and cells (eg, macrophages, neutrophils, basophils, mast cells, etc.). These components are “ready to go” and protect the body during the first few days of infection. In some cases, this is enough to eliminate the pathogen, but in other cases, the first defence is overwhelmed and a second line of defence is activated.
  • Adaptive immunity is the second line of defence that involves accumulating memory of encountered infections in order to mount an enhanced response specific to the pathogen or foreign substance. Adaptive immunity involves antibodies, which typically target foreign pathogens that roam freely in the bloodstream. T cells are also involved, which specifically target pathogens that have colonized the cells and can directly kill infected cells or help control the antibody response.

Immune dysfunction and clinical immunology

The immune system is a highly regulated and balanced system, and when the balance is disturbed, the disease can occur. Research in this area involves the study of diseases caused by a dysfunction of the immune system. Much of this work is of importance in developing new therapies and treatments that can control or cure the condition by altering the way the immune system works or, in the case of vaccines, prime the immune system and stimulate the immune reaction to specific pathogens.

1. Immunodeficiency disorders involve problems with the immune system that impair its ability to mount an adequate defence. As a result, they are almost always associated with serious infections that persist, recur, and/or lead to complications, making these disorders severely debilitating and even fatal. There are two types of immunodeficiency disorders: Primary immunodeficiencies are usually present from birth, are usually inherited, and are relatively rare. Such an example is the common variable immunodeficiency (CVID). Secondary immunodeficiencies usually develop later in life and can result after infection, as is the case with AIDS after HIV infection.

2. Autoimmune diseases occur when the immune system attacks the body it is supposed to protect. People with autoimmune diseases have a defect that prevents them from distinguishing “self” from “foreign” or “foreign” molecules. The principles of immunology have provided a wide variety of laboratory tests for the detection of autoimmune diseases. Autoimmune diseases can be described as “primary” autoimmune diseases, such as type 1 diabetes, which can manifest from birth or during the first years of life; or as ‘secondary’ autoimmune diseases, which manifest later in life due to various factors. Rheumatoid arthritis and multiple sclerosis are thought to belong to this type of autoimmunity. Furthermore, autoimmune diseases can be localized, such as Crohn’s disease that affects the GI tract, or systemic, such as systemic lupus erythematosus (SLE).

3. Allergies are hypersensitivity disorders that occur when the body’s immune system reacts against harmless foreign substances, causing damage to the body’s own tissues. Almost any substance can cause allergies (an allergen), but more commonly, allergies arise after eating certain types of food, such as peanuts, or inhaling airborne substances, such as pollen or dust. In allergic reactions, the body believes that the allergens are dangerous and immediately produces substances to attack them. This causes cells of the immune system to release powerful chemicals like histamine, which causes inflammation and many of the symptoms associated with allergies. Immunology strives to understand what happens to the body during an allergic response and the factors responsible for causing them. This should lead to better methods of diagnosis, prevention and control of allergic diseases.

4. Asthma is a debilitating and sometimes fatal disease of the airways. It usually occurs when the immune system responds to particles inhaled from the air and, over time, can cause patients’ airways to thicken. It is one of the main causes of disease and is especially common in children. In some cases it has an allergic component, however, in several cases, the origin is more complex and little known.

5. Cancer is a disease of abnormal and uncontrolled cell growth and proliferation and is defined by a number of characteristics, one of which is the ability of cancer cells to avoid immune destruction. Knowing that evasion of the immune system can contribute to cancer, researchers have turned to manipulate the immune system to defeat cancer (immunotherapy). Cancer immunotherapy seeks to stimulate the innate powers of the immune system to fight cancerous tissue and has shown tremendous promise as a new weapon in our arsenal against disease. Other applications of immunological knowledge against cancer include the use of monoclonal antibodies (proteins that seek out and bind directly to a specific target protein called an antigen. An example is Herceptin, which is a monoclonal antibody used to treat breast cancer and of the stomach). In addition, several successful cancer vaccines have been developed, in particular the HPV vaccine.

6. Transplants involve the transfer of cells, tissues, or organs from a donor to a recipient. The most formidable barrier to transplantation is the recognition by the immune system of the transplanted organs as foreign. Understanding the mechanisms and clinical features of rejection is important in determining a diagnosis, recommending treatment, and is critical to developing new strategies and medications to control transplants and limit the risk of rejection.

7. Vaccines are agents that teach the body to recognize and defend against infection from harmful pathogens, such as bacteria, viruses, and parasites. Vaccines provide a sneaky ‘preview’ of a specific pathogen, stimulating the body’s immune system to prepare should an infection occur. Vaccines contain a harmless component of the infectious agent that stimulates the immune system to mount a response, beginning with the production of antibodies. Vaccine-responsive cells proliferate to make antibodies specific for the provocative agent and also to form “memory cells.” Upon encountering the infectious agent a second time, these memory cells can quickly deal with the threat by producing sufficient amounts of antibodies. Pathogens within the body are eventually destroyed, preventing further infection. Several infectious diseases, such as smallpox, measles, mumps, rubella, diphtheria, tetanus, whooping cough, tuberculosis and polio, no longer pose a threat in Europe thanks to the successful application of vaccines.

Veterinary immunology

Veterinary immunology is a branch of immunology dedicated to improving animal health. Just like humans, animals also suffer from diseases caused when organisms try to invade their bodies or when their immune systems are not working properly. Wild, domestic, and farm animals are commonly exposed to a wide range of dangerous bacteria, viruses, and parasites that threaten their well-being. Animal infections can have widespread effects on human occupational sectors, such as food and agriculture.

Additionally, many animal infections can naturally be transmitted across the species barrier to infect humans and vice versa, a process termed zoonosis. For example, well-studied infections such as swine and avian influenza, as well as malaria and Lyme disease, are due to transmission from animals and insects to humans. Therefore, it is extremely important that these types of diseases are effectively controlled. These measures not only prevent further transmission to other animals and humans but also reduce potentially devastating social and economic consequences.