Immunology is a broad branch of biomedical science that covers the study of all aspects of the immune system in all organisms. It deals with, among other things, the physiological functioning of the immune system in states of both health and disease; malfunctions of the immune system in immunological disorders (autoimmune diseases, hypersensitivities, immune deficiency, allograft rejection); the physical, chemical and physiological characteristics of the components of the immune system in vitro, in situ, and in vivo. Immunology has various applications in several disciplines of science, and as such is further divided. Health science is the discipline of applied science which deals with human and animal health. ... Wikimedia Commons has media related to: Science For the scientific journal named Science, see Science (journal). ... The immune system is the system of specialised cells and organs that protect an organism from outside biological influences. ... In biology and ecology, an organism (in Greek organon = instrument) is a complex adaptive system of organs that influence each other in such a way that they function as a more or less stable whole and have properties of life. ... Physiology (in Greek physis = nature and logos = word) is the study of the mechanical, physical, and biochemical functions of living organisms. ... Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. ... Hypersensitivity is the name given to a state in which an immune response damages the bodys own tissues. ... In medicine, immune deficiency (or immunodeficiency) is a state where the immune system is incapable of defending the organism from infectious disease. ... An organ transplant is the transplantation of an organ (or part of one) from one body to another, for the purpose of replacing the recipients damaged or failing organ with a working one from the donor. ... Wiktionary has a definition of: In vitro In vitro (Latin: within glass) means within a test tube, or, more generally, outside a living organism or cell. ... In situ (in place in Latin), a term used in: biology, where it means to examine the phenomenon exactly in place where it occurs (without removing it in some special medium etc. ... In vivo (Latin for (with)in the living). ...

Histological examination of the immune system

Even before the concept of immunity (from immunis, Latin for "exempt") was developed, numerous early physicians characterised organs that would later prove to be part of the immune system. The key organs of the immune system are thymus, spleen, bone marrow, lymph vessels, lymph nodes and secondary lymphatic tissues such as tonsils, adenoids, and skin. Two major organs, the thymus and spleen, are examined histologically only post-mortem during autopsy. However some lymph nodes and secondary lymphatic tissues can be surgically excised for examination while patients are still alive. In a medical sense, immunity is a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion. ... In human anatomy, the thymus is a ductless gland located in the upper anterior portion of the chest cavity. ... The spleen is a ductless, vertebrate gland that is not necessary for life but is closely associated with the circulatory system, where it functions in the destruction of old red blood cells and removal of other debris from the bloodstream, and also in holding a reservoir of blood. ... We are very sorry this search engine is being modified and customized at the moment. ... Lymph originates as blood plasma lost from the circulatory system, which leaks out into the surrounding tissues. ... Structure of the lymph node. ... The Palatine tonsils. ... Adenoids, or pharyngeal tonsils, are folds of lymphatic tissue covered by ciliated epithelium. ... Diagram of the layers of human skin In zootomy and dermatology, skin is an organ of the integumentary system composed of a layer of tissues that protect underlying muscles and organs. ... A thin section of lung tissue stained with hematoxylin and eosin. ... An autopsy, also known as a post-mortem examination or an obduction, is a medical procedure that consists of a thorough examination of a corpse to determine the cause and manner of a persons death and to evaluate any disease or injury that may be present. ... A typical modern surgery operation Surgery (from the Greek cheirourgia meaning hand work) is the medical specialty that treats diseases or injuries by operative manual and instrumental treatment. ...

Many components of the immune system are actually cellular in nature and not associated with any specific organ but rather are embedded or circulating in various tissues located throughout the body. Cells in culture, stained for keratin (red) and DNA (green) The cell is the structural and functional unit of all living organisms, and are sometimes called the building blocks of life. ... Biological tissue is a group of cells that perform a similar function. ...

Classical immunology

Classical immunology ties in with the fields of epidemiology and medicine. It studies the relationship between the body systems, pathogens, and immunity. The earliest written mention of immunity can be traced back to the plague of Athens in 430 BCE. Thucydides noted that people who had recovered from a previous bout of the disease could nurse 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. Epidemiology is the study of the distribution and determinants of disease in human populations (Rothman and Greenland), and the application of this study to control health problems (Last 2001). ... See also Medical doctor (BE), Physician (AE), and Medical school. ... A pathogen or infectious agent is a biological agent that causes disease or illness to its host. ... A pandemic, or global epidemic, is an outbreak of an infectious disease that affects people over an extensive geographical area (from Greek pan all + demos people). ... Athens (Greek: Αθήνα, Athína; IPA ) is the capital of Greece, and of the Attica prefecture of Greece. ... Centuries: 6th century BC - 5th century BC - 4th century BC Decades: 480s BC 470s BC 460s BC 450s BC 440s BC - 430s BC - 420s BC 410s BC 400s BC 390s BC 380s BC Years: 435 BC 434 BC 433 BC 432 BC 431 BC - 430 BC - 429 BC 428 BC... Bust of Thucydides Thucydides (between 460 and 455 BC–circa 400 BC, Greek Θουκυδίδης, Thoukudídês) was an ancient Greek historian, and the author of the History of the Peloponnesian War, which recounts the 5th century BC war between Sparta and Athens. ... A nurse is a health care professional who is engaged in the practice of nursing. ... Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ... (19th century - 20th century - 21st century - more centuries) Decades: 1900s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s As a means of recording the passage of time, the 20th century was that century which lasted from 1901–2000 in the sense of the Gregorian calendar (1900–1999 in the...

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 and cellular components. Innate immunity is immunity that the body possesses naturally, as opposed to adaptive immunity. ... Humoral immunity is mediated by secreted antibodies, produced in the cells of the B lymphocyte lineage (B cell). ... Cell-mediated immunity is an immune response that does not involve antibodies but rather involves the activation of macrophages and NK-cells, the production of 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 and antigens. 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. Schematic of antibody binding to an antigen An antibody is a protein used by the immune system to identify and neutralize foreign objects like bacteria and viruses. ... An antigen is a molecule that stimulates the production of antibodies. ...

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. The 21st century is the century that began on 1 January 2001 and will last to 31 December 2100. ...

Clinical immunology

Clinical immunology is the study of diseases caused by the immune system and diseases of the immune system from a medical perspective. Clinical immunology is the study of diseases caused by the immune system and diseases of the immune system from a medical perspective. ... A disease is any abnormal condition of the body or mind that causes discomfort, dysfunction, or distress to the person affected or those in contact with the person. ...

Many diseases caused by the immune system fall into two broad categories: immunodeficiency, in which parts of the immune system fail to provide an adequate response (examples include chronic granulomatous disease), and autoimmunity, in which the immune system attacks its own host's body (examples include systemic lupus erythematosus, rheumatoid arthritis, Hashimoto's disease and myasthenia gravis). Other immune system disorders include different hypersensitivities, in which the system responds inappropriately to harmless compounds (asthma and allergies) or responds too intensely. In medicine, immune deficiency (or immunodeficiency) is a state where the immune system is incapable of defending the organism from infectious disease. ... In medicine (genetics and pediatrics) chronic granulomatous disease (CGD) is a hereditary disease where neutrophil granulocytes are unable to destroy ingested pathogens. ... Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. ... Rheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disorder that causes the immune system to attack the joints. ... Hashimotos thyroiditis is the most common form of thyroiditis, an autoimmune disease where the bodys own antibodies fight the cells of the thyroid. ... Myasthenia gravis (MG, Latin: grave muscle weakness) is a neuromuscular disease leading to fluctuating weakness and fatiguability. ... Hypersensitivity is the name given to a state in which an immune response damages the bodys own tissues. ... An allergy or Type I hypersensitivity is an immune malfunction whereby a persons body is hypersensitised to react immunologically to typically nonimmunogenic substances. ...

The most well-known disease that affects the immune system itself is AIDS, caused by the HIV virus. AIDS is an immunodeficiency characterized by the lack of CD4+ ("helper") T cells and macrophages, which are destroyed by the HIV virus. AIDS (Acquired Immunodeficiency Syndrome or Acquired Immune Deficiency Syndrome, sometimes written Aids) is a human disease characterized by progressive destruction of the bodys immune system. ... The human immunodeficiency virus (HIV) is a frequently mutating retrovirus that attacks the human immune system and which has been shown to cause acquired immune deficiency syndrome (AIDS). ... T cells are a subset of lymphocytes that play a large role in the immune response. ... Macrophages (Greek: big eaters) are cells found in tissues that are responsible for phagocytosis of pathogens, dead cells and cellular debris. ...

Clinical immunologists also study ways to prevent transplant rejection, in which the immune system attempts to destroy allografts or xenografts. Transplant rejection occurs when the immune system of the recipient of an transplant attacks the transplanted organ or tissue. ... An allograft is a transplanted organ or tissue from a genetically non-identical member of the same species. ... A xenograft (xenotransplant) is a transplant of tissue from a donor of one species to a recipient of another species. ...

Immunotherapy

See main article Immunotherapy Immunotherapy is a form of medical treatment based upon the concept of modulating the immune system to achieve a therapeutic 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 cancers together with chemotherapy (drugs) and radiotherapy (radiation). However, immunotherapy is also often used in the immunosuppressed (such as HIV patients) and people suffering from other immune deficiencies or autoimmune diseases. When normal cells are damaged beyond repair, they are eliminated by apoptosis. ... Chemotherapy is the use of chemical substances to treat disease. ... A medication is a licenced drug taken to cure or reduce symptoms of an illness or medical condition. ... Radiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). ... Electromagnetic radiation can be conceptualized as a self propagating transverse oscillating wave of electric and magnetic fields. ... Human immunodeficiency virus, commonly known by the acronym HIV, is a retrovirus that primarily infects vital components of the human immune system such as CD4+ T cells, macrophages and dendritic cells. ...

Diagnostic immunology

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 can be conjugated with a radiolabel, fluorescent label, or color-forming enzyme and are used as a "probe" to detect it. An antigen is a molecule that stimulates the production of antibodies. ...

Well known applications of this include immunoblotting, ELISA and immunohistochemical staining of microscope slides. The speed, accuracy and simplicity of such tests has led to the development of rapid techniques for the diagnosis of disease, microbes and even illegal drugs in vivo (of course tests conducted in a closed environment have a higher degree of accuracy). Such testing is also used to distinguish compatible blood types. The Enzyme-Linked Immunosorbent Assay (ELISA or EIA for short) is a biochemical technique used in immunology to detect the presence of an antibody or an antigen in a sample. ... In vivo (Latin for (with)in the living). ... A blood type is a description of an individuals characteristics of red blood cells due to substances (carbohydrates and proteins) on the cell membrane. ...

Evolutionary immunology

Study of the immune system in extant and extinct species is capable of giving us a key understanding of the evolution of species and the immune system. In biology and ecology, extinction is the ceasing of existence of a species or group of taxa. ... A speculatively rooted phylogenetic tree of all living things, based on rRNA gene data, showing the separation of the three domains, bacteria, archaea, and eukaryotes, as described initially by Carl Woese. ...

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 recognised, 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. Anthropocentrism (Greek άνθρωπος, anthropos, man, human being, κέντρον, kentron, center) is the practice, conscious or otherwise, of regarding the existence and/or concerns of human beings as the central fact of the universe. ...

Insects and other arthropods, 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 chitinous shells. Classes & Orders Subclass: Apterygota Orders Archaeognatha (Bristletails) Thysanura (Silverfish) Monura - extinct Subclass: Pterygota Infraclass: Paleoptera (paraphyletic) Orders Ephemeroptera (mayflies) Protodonata - extinct Odonata (dragonflies and damselflies) Diaphanopteroidea - extinct Palaeodictyoptera - extinct Megasecoptera - extinct Archodonata - extinct Infraclass: Neoptera Orders Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Dermaptera (earwigs) Plecoptera (stoneflies) Protorthoptera - extinct Orthoptera (grasshoppers... Subphyla and Classes Subphylum Trilobitomorpha Trilobita - Trilobites (extinct) Subphylum Chelicerata Arachnida - Spiders, Scorpions, etc. ... Structure of chitin molecule In biology, chitin (pronounced keye-tin) is one of the main components in the cell walls of fungi, the exoskeletons of insects and other arthropods, and in some other animals. ...

See also

• Immune system
• autoimmunity
• List of immunologists

The immune system is the system of specialised cells and organs that protect an organism from outside biological influences. ... Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. ... This is a list of some noted immunologists. ...

References

• Wikibooks Immunology Textbook
• Goldsby RA, Kindt TK, Osborne BA and Kuby J (2003) Immunology, 5th Edition, W.H. Freeman and Company, New York, New York, ISBN 0-7167-4947-5