immunology, branch of medicine that studies the response of organisms to foreign substances, e.g., viruses virus, parasite with a noncellular structure composed mainly of nucleic acid within a protein coat. Viruses usually are too small (100–2,000 Angstrom units) to be seen with the light microscope and thus must be studied by electron microscopes.
..... Click the link for more information. , bacteria bacteria [pl. of bacterium], microscopic unicellular prokaryotic organisms characterized by the lack of a membrane-bound nucleus and membrane-bound organelles. Once considered a part of the plant kingdom, bacteria were eventually placed in a separate kingdom, Monera .
..... Click the link for more information. , and bacterial toxins toxin, poison produced by living organisms. Toxins are classified as either exotoxins or endotoxins. Exotoxins are a diverse group of soluble proteins released into the surrounding tissue by living bacterial cells.
..... Click the link for more information. (see immunity immunity, ability of an organism to resist disease by identifying and destroying foreign substances or organisms. Although all animals have some immune capabilities, little is known about nonmammalian immunity.
..... Click the link for more information. ). Immunologists study the tissues and organs of the immune system (bone marrow, spleen spleen, soft, purplish-red organ that lies under the diaphragm on the left side of the abdominal cavity. The spleen acts as a filter against foreign organisms that infect the bloodstream, and also filters out old red blood cells from the bloodstream and decomposes
..... Click the link for more information. , tonsils tonsils, name commonly referring to the palatine tonsils, two ovoid masses of lymphoid tissue situated on either side of the throat at the back of the tongue.
..... Click the link for more information. , thymus, lymphatic system lymphatic system (lĭmfăt`ĭk)
..... Click the link for more information. ), its specialized cells (e.g., B and T lymphocytes and antibodies antibody, protein produced by the immune system (see immunity ) in response to the presence in the body of antigens: foreign proteins or polysaccharides such as bacteria, bacterial toxins , viruses, or other cells or proteins.
..... Click the link for more information. ), and the influence of genetic, nutritional, and other factors on the immune system. They also study disease-causing organisms to determine how they injure the host and help to develop vaccines (see vaccination vaccination, means of producing immunity against pathogens, such as viruses and bacteria, by the introduction of live, killed, or altered antigens that stimulate the body to produce antibodies against more dangerous forms.
..... Click the link for more information. ).

In addition to studying the normal workings of the immune system, immunologists study unwanted immune responses such as allergies allergy, hypersensitive reaction of the body tissues of certain individuals to certain substances that, in similar amounts and circumstances, are innocuous to other persons. Allergens, or allergy-causing substances, can be airborne substances (e.g.
..... Click the link for more information. , essentially immunological responses of the body to substances or organisms that, as a rule, do not affect most people, and autoimmune diseases autoimmune disease, any of a number of abnormal conditions caused when the body produces antibodies to its own substances. In rheumatoid arthritis , a group of antibody molecules called collectively RF, or rheumatoid factor, is complexed to the individual's own gamma
..... Click the link for more information. (e.g., rheumatoid arthritis arthritis, painful inflammation of a joint or joints of the body, usually producing heat and redness. There are many kinds of arthritis. In its various forms, arthritis disables more people than any other chronic disorder.
..... Click the link for more information. and lupus erythematosus) which occur when the body reacts immunologically to some of its own constituents.

Immunologists have developed a large number of procedures have been developed to detect and measure quantities of immunologically active substances such as circulating antibodies and immune globulins globulin, any of a large family of proteins of a spherical or globular shape that are widely distributed throughout the plant and animal kingdoms. Many of them have been prepared in pure crystalline form.
..... Click the link for more information. . Immune globulins that can be given intravenously (IVIGs) have been found to be more effective against antibody deficiencies and certain autoimmune diseases than their older intramuscular counterparts; their use in a wide spectrum of bacterial and viral infections is under study. Current research in immunology is also aimed at understanding the role of T lymphocytes (see immunity), which play a major part in the body's defenses against infections and neoplasms neoplasm or tumor, tissue composed of cells that grow in an abnormal way. Normal tissue is growth-limited, i.e., cell reproduction is equal to cell death.
..... Click the link for more information. . AIDS AIDS or acquired immunodeficiency syndrome, fatal disease caused by a rapidly mutating retrovirus that attacks the immune system and leaves the victim vulnerable to infections, malignancies, and neurological disorders.
..... Click the link for more information. , for example, is the disease that results when the HIV HIV (Human Immunodeficiency Virus), either of two closely related retroviruses that invade T-helper lymphocytes and are responsible for AIDS . There are two types of HIV: HIV-1 and HIV-2. HIV-1 is responsible for the vast majority of AIDS in the United States.
..... Click the link for more information. virus destroys certain of these T cells.

Bibliography

See studies by R. Desowitz (1988) and R. Gallo (1991).

immunology

Science dealing with the body's defenses against disease-causing microorganisms and disorders of those defenses. Starting with Edward Jenner's use of a vaccine against smallpox in 1796, immunology has arrived at a comprehensive and sophisticated understanding of the role of microorganisms in disease and of the formation, mobilization, action, and interaction of antibodies and antigen-reactive cells. It covers treatment of allergies, immunosuppression after organ transplants to prevent rejection, and study of autoimmune diseases and immunodeficiencies. AIDS has stimulated intensive research in the last of these.

immunology

the branch of biological science concerned with the study of immunity

Immunology

The division of biological science concerned with the native or acquired response of complex living organisms to the intrusion of other organisms or foreign substances. The immune system allows the host organism to distinguish between self and nonself and to respond to a target (termed an antigen).

It was not until the germ theory of infectious disease was established that the full implication of immunology was realized. First came the recognition that certain bacteria caused corresponding diseases. Second came the recognition that it was a specific resistance to that bacterium or its toxins that prevented recurrence of the same disease. Third came the discovery that after recovery from an infectious disease, protective substances called antibodies could be found in the blood of animals and humans. Antigens, such as bacteria and their products, triggered the production of antibodies and indeed all kinds of chemical and biological molecules. The action of these effector mechanisms, however, has come to be recognized as being not always protective or conferring immunity, but sometimes becoming grossly exaggerated or inappropriate, or capable of turning upon the host in a destructive fashion that causes disease. These responses are classified as allergies. Illnesses associated with a misguided response of the immune system that is directed against the self and results from a breakdown in the normal immunological tolerance of, or unresponsiveness to, self antigens are termed autoimmune. The mechanisms responsible for these disorders are unknown but probably include the intervention of factors such as viruses that either modify or naturally resemble self molecules. Subsequently, the immune response, in seeking out what is foreign, proceeds to attack the self. See Allergy, Autoimmunity

Immunology is also concerned with assaying the immune status of the host through a variety of serological procedures, and in devising methods of increasing host resistance through prophylactic vaccination. There has also been much important investigation of induced resistance and tolerance to transplants of skin and organs, including tumors. See Blood groups, Hypersensitivity, Immunity, Immunoassay, Isoantigen, Phagocytosis, Serology, Transplantation biology, Vaccination

immunology (redirected from immunologist)

Bibliography

immunology

immunology
(redirected from immunologist)