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Immunology is a broad branch of biomedical science
Science

In its broadest sense, science refers to any systematic knowledge or practice. In its more usual restricted sense, science refers to a system of acquiring knowledge based on scientific method, as well as to the organized body of knowledge gained through such research....
 that covers the study of all aspects of the immune system
Immune system

An immune system is a collection of biological processes within an organism that protects against disease by identifying and killing pathogens and tumour cells....
 in all organism
Organism

In biology, an organism is any life thing . In at least some form, all organisms are capable of response to stimulus , reproduction, growth and developmental biology, and maintenance of homeostasis as a stable whole....
s. It deals with, among other things, the physiological
Physiology

Physiology is the study of the mechanical, physical, and biochemical functions of living organisms. Physiology has traditionally been divided between plant physiology and animal and all living things physiology but the principles of physiology are universal, no matter what particular organism is being studied....
 functioning of the immune system in states of both health and disease; malfunctions of the immune system in immunological disorders (autoimmune diseases, hypersensitivities
Hypersensitivity

Hypersensitivity refers to undesirable reactions produced by the normal immune system. Hypersensitivity reactions require a pre-sensitized state of the host....
, immune deficiency, transplant rejection
Transplant rejection

Transplant rejection occurs when a Organ transplant organ or tissue is not accepted by the body of the transplant recipient. This is explained by the concept that the immune system of the recipient attacks the transplanted organ or tissue....
); the physical, chemical and physiological characteristics of the components of the immune system in vitro
In vitro

In vitro refers to the technique of performing a given procedure in a controlled environment outside of a living organism. Some may argue that in vitro refers to a process that is created in a "test tube"; however, Robert Kail and John Cavanaugh on page 58 in the 4th edition of Human Development: A Life-Span View cite that in fact th...
, in situ
In situ

In situ is a Latin phrase meaning in the place. It is used in many different contexts....
, and in vivo
In vivo

In vivo means that which takes place inside an organism. In science, in vivo refers to experimentation done in or on the living tissue of a whole, living organism as opposed to a partial or dead one or a in vitro....
.






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Immunology is a broad branch of biomedical science
Science

In its broadest sense, science refers to any systematic knowledge or practice. In its more usual restricted sense, science refers to a system of acquiring knowledge based on scientific method, as well as to the organized body of knowledge gained through such research....
 that covers the study of all aspects of the immune system
Immune system

An immune system is a collection of biological processes within an organism that protects against disease by identifying and killing pathogens and tumour cells....
 in all organism
Organism

In biology, an organism is any life thing . In at least some form, all organisms are capable of response to stimulus , reproduction, growth and developmental biology, and maintenance of homeostasis as a stable whole....
s. It deals with, among other things, the physiological
Physiology

Physiology is the study of the mechanical, physical, and biochemical functions of living organisms. Physiology has traditionally been divided between plant physiology and animal and all living things physiology but the principles of physiology are universal, no matter what particular organism is being studied....
 functioning of the immune system in states of both health and disease; malfunctions of the immune system in immunological disorders (autoimmune diseases, hypersensitivities
Hypersensitivity

Hypersensitivity refers to undesirable reactions produced by the normal immune system. Hypersensitivity reactions require a pre-sensitized state of the host....
, immune deficiency, transplant rejection
Transplant rejection

Transplant rejection occurs when a Organ transplant organ or tissue is not accepted by the body of the transplant recipient. This is explained by the concept that the immune system of the recipient attacks the transplanted organ or tissue....
); the physical, chemical and physiological characteristics of the components of the immune system in vitro
In vitro

In vitro refers to the technique of performing a given procedure in a controlled environment outside of a living organism. Some may argue that in vitro refers to a process that is created in a "test tube"; however, Robert Kail and John Cavanaugh on page 58 in the 4th edition of Human Development: A Life-Span View cite that in fact th...
, in situ
In situ

In situ is a Latin phrase meaning in the place. It is used in many different contexts....
, and in vivo
In vivo

In vivo means that which takes place inside an organism. In science, in vivo refers to experimentation done in or on the living tissue of a whole, living organism as opposed to a partial or dead one or a in vitro....
. Immunology has applications in several disciplines of science, and as such is further divided.

Immunology is that branch of biomedical science,which deals with the study of normal and malfunctions of immune system in all organisms.

Histological examination of the immune system

Even before the concept of immunity
Immunity (medical)

Immunity is a medical term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion....
 (from immunis, Latin for "exempt") was developed, numerous early physicians characterized organs that would later prove to be part of the immune system. The key primary lymphoid organs of the immune system are thymus
Thymus

In human anatomy, the thymus is an organ located in the upper anterior portion of the Thoracic cavity just behind the sternum. The main function of the thymus is to provide an area for T lymphocyte maturation....
 and bone marrow
Bone marrow

Bone marrow is the flexible biological tissue found in the hollow interior of bones. In adults, marrow in large bones produces new blood cells....
, and secondary lymphatic tissues such as spleen
Spleen

The spleen is an organ found in all vertebrate animals. In humans, the spleen is located in the abdomen of the body, where it functions in the destruction of redundant red blood cells, and holds a reservoir of blood....
, tonsil
Tonsil

Palatine tonsils, occasionally called the faucial tonsils, are the tonsils that can be seen on the left and right sides at the back of the throat....
s, lymph vessels
Lymphatic system

The lymphatic system in vertebrates is a network of conduits that carry a clear fluid called lymph. It also includes the lymphoid tissue through which the lymph travels....
, lymph node
Lymph node

A Lymph node is an organ consisting of many types of cells, and is a part of the lymphatic system. Lymph nodes are found all through the body, and act as filters or traps for foreign particles....
s, adenoid
Adenoid

Adenoids are a mass of lymphoid tissue situated at the very back of the nose, in the roof of the nasopharynx, where the nose blends into the mouth....
s, and skin
Skin

The skin is the outer covering of the body, also known as the epidermis. It is the largest organ of the integumentary system made up of multiple layers of epithelial biological tissue, and guards the underlying muscles, bones, ligaments and organ s....
. When health conditions warrant, immune system organs including the thymus, spleen, portions of bone marrow, lymph nodes and secondary lymphatic tissues can be surgically
Surgery

Surgery is a medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, to help improve bodily function or appearance, or sometimes for some other reason....
 excised for examination while patients are still alive.

Many components of the immune system are actually cell
Cell (biology)

The cell is the structural and functional unit of all known Life organisms. It is the smallest unit of an organism that is classified as living, and is often called the building bricks of life....
ular in nature and not associated with any specific organ but rather are embedded or circulating in various tissues located throughout the body.

Classical immunology


Classical immunology ties in with the fields of epidemiology
Epidemiology

Epidemiology is the study of factors affecting the health and illness of populations, and serves as the foundation and logic of interventions made in the interest of public health and preventive medicine....
 and medicine
Medicine

Medicine is the art and science of healing. It encompasses a range of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
. It studies the relationship between the body systems, pathogen
Pathogen

A pathogen , infectious agent, or germ, is a biological agent that causes disease or illness to its Host .There are several substrates and pathways whereby pathogens can invade a host; the principal pathways have different episodic time frames, but soil contamination has the longest or most persistent potential for harboring...
s, and immunity. The earliest written mention of immunity can be traced back to the plague
Pandemic

A pandemic is an epidemic of infectious disease that spreads through populations across a large region; for instance a continent, or even worldwide....
 of Athens
Athens

Athens , the Capital and largest city of Greece, dominates the Attica periphery; as one of the List of cities by time of continuous habitation, its recorded history spans around 3,400 years....
 in 430 BCE. Thucydides
Thucydides

Thucydides was a Greeks history and author of the History of the Peloponnesian War, which recounts the 5th century B.C. war between Sparta and Athens to the year 411 B.C....
 noted that people who had recovered from a previous bout of the disease could nurse
Nurse

A nurse is a healthcare professional, who along with other health care professionals, is responsible for the treatment, safety, and recovery of Acute or Chronic ill or injured people, health maintenance of the healthy, and treatment of life-threatening emergencies in a wide range of health care settings....
 the sick without contracting the illness a second time. Many other ancient societies have references to this phenomenon, but it was not until the 19th and 20th centuries before the concept developed into scientific theory.

The study of the molecular and cellular components that comprise the immune system, including their function and interaction, is the central science of immunology. The immune system has been divided into a more primitive innate immune system, and acquired or adaptive immune system of vertebrates, the latter of which is further divided into humoral
Humoral immunity

The Humoral Immune Response is the aspect of immunity that is mediated by secreted antibodies produced in the cells of the B lymphocyte lineage ....
 and cellular components
Cell-mediated immunity

Cell-mediated immunity is an immune response that does not involve antibodies or complement system but rather involves the activation of macrophages, natural killer cells , antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen....
.

The humoral (antibody) response is defined as the interaction between antibodies
Antibody

Antibodies are gamma globulin proteins that are found in blood or other bodily fluids of vertebrates, and are used by the immune system to identify and neutralize foreign objects, such as bacterium and viruses....
 and antigen
Antigen

An antigen is a substance that prompts the generation of antibodies and can cause an immune response. The word originated from the notion that they can stimulate antibody generation....
s. Antibodies are specific proteins released from a certain class of immune cells (B lymphocytes). Antigens are defined as anything that elicits generation of antibodies, hence they are Antibody Generators. Immunology itself rests on an understanding of the properties of these two biological entities. However, equally important is the cellular response, which can not only kill infected cells in its own right, but is also crucial in controlling the antibody response. Put simply, both systems are highly interdependent.

In the 21st century, immunology has broadened its horizons with much research being performed in the more specialized niches of immunology. This includes the immunological function of cells, organs and systems not normally associated with the immune system, as well as the function of the immune system outside classical models of immunity.

Clinical immunology

Clinical immunology is the study of disease
Disease

A disease or medical condition is an abnormal condition of an organism that impairs bodily functions, associated with specific symptoms and Medical signs....
s caused by disorders of the immune system (failure, aberrant action, and malignant growth of the cellular elements of the system). It also involves diseases of other systems, where immune reactions play a part in the pathology and clinical features.

The diseases caused by disorders of the immune system fall into two broad categories: immunodeficiency
Immunodeficiency

Immunodeficiency is a state in which the immune system's ability to fight infectious disease is compromised or entirely absent. Most cases of immunodeficiency are acquired but some people are born with defects in the immune system, or primary immunodeficiency....
, in which parts of the immune system fail to provide an adequate response (examples include chronic granulomatous disease
Chronic granulomatous disease

Chronic granulomatous disease is a diverse group of genetic disorder in which certain cells of the immune system have difficulty forming the reactive oxygen compounds used to kill certain ingested pathogens....
), and autoimmunity
Autoimmunity

Autoimmunity is the failure of an organism to recognize its own constituent parts as self, which results in an immune response against its own cells and tissues....
, in which the immune system attacks its own host's body (examples include systemic lupus erythematosus
Systemic lupus erythematosus

Systemic lupus erythematosus is a chronic Autoimmunity connective tissue disease that can affect any part of the body. As occurs in other autoimmune diseases, the immune system attacks the body?s cells and tissue, resulting in inflammation and tissue damage....
, rheumatoid arthritis
Rheumatoid arthritis

Rheumatoid arthritis is a chronic, systemic disease inflammation that may affect many tissues and organs, but principally attacks the joints producing a inflammatory synovitis that often progresses to destruction of the articular cartilage and ankylosis of the joints....
, Hashimoto's disease and myasthenia gravis
Myasthenia gravis

Myasthenia gravis is a neuromuscular disease leading to fluctuating muscle weakness and fatigue . It is an autoimmunity, in which weakness is caused by circulating antibody that block acetylcholine receptors at the post-synaptic neuromuscular junction, inhibiting the stimulative effect of the neurotransmitter acetylcholine....
). Other immune system disorders include different hypersensitivities
Hypersensitivity

Hypersensitivity refers to undesirable reactions produced by the normal immune system. Hypersensitivity reactions require a pre-sensitized state of the host....
, in which the system responds inappropriately to harmless compounds (asthma
Asthma

Asthma is a common chronic obstructive pulmonary disease, in which the Lung constrict, become inflammation, and are lined with excessive amounts of thickened mucus, often in response to one or more triggers....
 and other allergies
Allergy

Allergy is a Disorder of the immune system often also referred to as atopy. Allergic reactions occur to Natural environmental substances known as allergens; these reactions are Acquired disorder, predictable and rapid....
) or responds too intensely.

The most well-known disease that affects the immune system itself is AIDS, caused by HIV
HIV

Human immunodeficiency virus is a lentivirus that can lead to AIDS , a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections....
. AIDS is an immunodeficiency characterized by the lack of CD4+ ("helper") T cells and macrophages, which are destroyed by HIV.

Clinical immunologists also study ways to prevent transplant rejection
Transplant rejection

Transplant rejection occurs when a Organ transplant organ or tissue is not accepted by the body of the transplant recipient. This is explained by the concept that the immune system of the recipient attacks the transplanted organ or tissue....
, in which the immune system attempts to destroy allografts or xenografts.

Immunotherapy

See main article Immunotherapy
Immunotherapy

Immunotherapy, in medicine, refers to an array of treatment strategies based upon the concept of modulating the immune system to achieve a Prophylaxis and/or Immunosuppressive therapy goal....


The use of immune system components to treat a disease or disorder is known as immunotherapy. Immunotherapy is most commonly used in the context of the treatment of cancer
Cancer

Cancer is a class of diseases in which a group of cell display uncontrolled growth , invasion , and sometimes metastasis . These three malignant properties of cancers differentiate them from benign tumors, which are self-limited, do not invade or metastasize....
s together with chemotherapy
Chemotherapy

Chemotherapy, in its most general sense, refers to treatment of disease by chemicals that kill cells, specifically those of micro-organisms or cancer....
 (drug
Medication

A pharmaceutical drug, also referred to as medicine or medicament, can be loosely defined as any substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease....
s) and radiotherapy (radiation
Electromagnetic radiation

Electromagnetic radiation takes the form of wave propagation waves in a vacuum or in matter. EM radiation has an electric field and magnetic field component which oscillate in phase perpendicular to each other and to the direction of energy Wave propagation....
). However, immunotherapy is also often used in the immunosuppressed (such as HIV
HIV

Human immunodeficiency virus is a lentivirus that can lead to AIDS , a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections....
 patients) and people suffering from other immune deficiencies or autoimmune diseases.

Diagnostic immunology

See main article Diagnostic immunology
Diagnostic immunology

Diagnostic immunology is a collective term for a variety of diagnostic techniques that rely on the specificity of the bond between antibody and antigens....
The specificity of the bond between antibody and antigen has made it an excellent tool in the detection of substances in a variety of diagnostic techniques. Antibodies specific for a desired antigen
Antigen

An antigen is a substance that prompts the generation of antibodies and can cause an immune response. The word originated from the notion that they can stimulate antibody generation....
 can be conjugated with a radiolabel, fluorescent label, or color-forming enzyme and are used as a "probe" to detect it.

Evolutionary immunology

Study of the immune system in extant and extinct
Extinction

In biology and ecology, extinction is the death of every member of a species or group of taxon. The moment of extinction is generally considered to be the death of the last individual of that species ....
 species is capable of giving us a key understanding of the evolution
Evolution

In biology, evolution is change in the heritability trait of a population of organisms from one generation to the next. These changes are caused by a combination of three main processes: variation, reproduction, and selection....
 of species and the immune system.

A development of complexity of the immune system can be seen from simple phagocytotic protection of single celled organisms, to circulating antimicrobial peptides in insects to lymphoid organs in vertebrates. Of course, like much of evolutionary observation, these physical properties are often seen from the anthropocentric aspect. It should be recognized that every organism living today has an immune system absolutely capable of protecting it from most forms of harm; those organisms that did not adapt their immune systems to external threats are no longer around to be observed.

Insect
Insect

Insects are the biggest class of arthropods and the only ones with wings. They are the most diverse group of animals on the planet. They are most diverse at the equator and their diversity declines toward the poles....
s and other arthropod
Arthropod

Arthropods are animals belonging to the Scientific classification Arthropoda , and include the insects, arachnids, crustaceans, and others....
s, while not possessing true adaptive immunity, show highly evolved systems of innate immunity, and are additionally protected from external injury (and exposure to pathogens) by their chitin
Chitin

Chitin n is a long-chain polymer of a N-acetylglucosamine, a derivative of glucose, and is found in many places throughout the natural world....
ous shells.

See also

  • Autoimmunity
    Autoimmunity

    Autoimmunity is the failure of an organism to recognize its own constituent parts as self, which results in an immune response against its own cells and tissues....
  • List of immunologists
    List of immunologists

    This is a list of notable immunology....
  • History of immunology
    History of immunology

    Timeline of immunology:* 1718 - Lady Mary Wortley Montagu, the wife of the British ambassador to Constantinople, observed the positive effects of variolation on the native population and had the technique performed on her own children....
  • Serology
    Serology

    Serology is the scientific study of Blood plasma. In practice, the term usually refers to the diagnostic identification of Antibody in the serum....
  • Immunodeficiency
    Immunodeficiency

    Immunodeficiency is a state in which the immune system's ability to fight infectious disease is compromised or entirely absent. Most cases of immunodeficiency are acquired but some people are born with defects in the immune system, or primary immunodeficiency....
  • Medical technologist
    Medical technologist

    File:Lab tech.JPGA medical technologist is a healthcare professional who performs diagnostic analytic tests on body fluids such as blood, urine, sputum, feces, cerebrospinal fluid , peritoneal fluid, pericardial fluid, and synovial fluid, as well as other specimens....
  • Osteoimmunology
    Osteoimmunology

    Osteoimmunology is the study of the interface between the skeleton and the immune system, comprising the ?osteo-immune system?. It is also the study of shared components and mechanisms between the two systems in vertebrates, including ligands, receptors, signaling molecules and transcription factors....


External links

  • Annual Review of Immunology ()
  • - BioMed Central
    BioMed Central

    BioMed Central is a United Kingdom-based for-profit scientific publisher specialising in open access publication. BMC publishes over 180 scientific journals, and describes itself as the first and largest open access science publisher....
    :Immunology is an open access journal
    Open access journal

    Open access journals are scholarly journals that are available to the reader "without financial or other barrier other than access to the internet itself." Some are subsidized, and some require payment on behalf of the author....
     publishing original peer-reviewed research articles.
  • Tests the effects of pharmaceuticals in the developmental stage on the immune system.
  • Searchable free online version at the National Center for Biotechnology Information
    National Center for Biotechnology Information

    The National Center for Biotechnology Information is part of the United States National Library of Medicine , a branch of the National Institutes of Health....
  • murine models for immunological disease
  • Nature Reviews Immunology
    Nature Reviews Immunology

    With an impact factor of 32.7, Nature Reviews Immunology [ISSN 1474-1733] is the leading monthly review title for immunology. Immunology is a diverse and growing discipline that can be defined as the study of the tissues, cells and molecules involved in host defence mechanisms, how the body defends itself against disease, and what happens whe...
     ()
  • - an NIAID-funded database resource of reference and experiment data covering the entire immunology domain
  • Interesting web site made by the faculty of medicine of the University of Geneva dealing with the immunological issues linked with the transplantation of materials genetically different between donor and recipient (hematopoietical stem cells, organs or the transfusion of blood).
  • University of South Carolina
  • Medical specialty organization