Immunology Glossary Flashcards

A complete set of vocabulary flashcards based on the provided immunology glossary notes.

Actinobacteria

A major phylum of Gram-positive bacteria with a high G+C content. They include important pathogens such as the Mycobacteria, Corynebacteria, and Rhodococcus.

Activated macrophage

A macrophage in a state of polarized metabolic and functional activity.

Active immunity

Immunity produced as a result of administration of an antigen, thus triggering an immune response.

Acute inflammation

Rapidly developing inflammation of recent onset. It is characterized by tissue infiltration by neutrophils.

Acute-phase proteins

Proteins, synthesized by the liver and other tissues, whose level in serum rises rapidly in response to acute inflammation and tissue damage.

Adjuvant

Any substance that, when given with an antigen, enhances the immune response to that antigen.

Adaptive immunity

Immunity that recognizes foreign invaders and adapts to them. As a result it improves with experience.

Adoptive immunity

Immunity that results from the transfer of cells from an immunized animal to an unimmunized recipient.

Affinity

The strength of binding between two molecules such as an antigen and antibody. Usually expressed as an association constant ($K_a$).

Affinity maturation

The progressive increase in antibody affinity for antigen that occurs during the course of an immune response as a result of somatic mutation in V genes.

Agammaglobulinemia

The absence of γ-globulins in blood.

Agglutination

The clumping of particulate antigens by antibodies.

Agnatha

A class of jawless fish. It includes the cyclostomes, an order containing the hagfish and lamprey.

Alarmins

Molecules released by dead or damaged tissues that trigger innate immune responses, especially inflammation.

Albumin

The blood protein largely responsible for maintaining plasma osmotic pressure.

Alleles

Different forms of a gene that occupy the same polymorphic locus.

Allelic exclusion

The expression of only one allelic protein by a cell from a heterozygous individual that has the genes to express both allelic proteins.

Allergens

Antigens that provoke allergic reactions. Usually type I hypersensitivity.

Allergic contact dermatitis

An inflammatory skin reaction mediated by Th1 cells responding to low-molecular-weight chemicals bound to skin cells.

Allergy

A hypersensitivity reaction initiated by specific immunological mechanisms.

Allogeneic

Genetically dissimilar animals of the same species.

Allograft

An organ graft between two genetically dissimilar animals of the same species.

Allotype

Phenotypic (antigenic and structural) differences between the proteins of different individuals of the same species as a result of transcription of different alleles.

Alternative complement pathway

The complement pathway triggered by the activation of C3 by the presence of an activating surface.

Amyloid

An extracellular, amorphous, waxy protein deposited in the tissues of individuals with a chronic inflammation or a myeloma. It consists of misfolded insoluble fibrillar proteins.

Analog

An organ or tissue that has the same function as another but is of different evolutionary origin.

Anamnestic response

A secondary immune response.

Anaphylactoid response

An inflammatory response that resembles anaphylaxis but is not mediated by IgE.

Anaphylatoxins

Complement fragments that stimulate mast cell degranulation and smooth muscle contraction.

Anaphylaxis

A severe, life-threatening generalized or systemic reaction due to an acute type I hypersensitivity response.

Anergy

The failure of a sensitized animal to respond to an antigen —a form of immunological tolerance.

Antibiotic

A chemical compound, usually obtained from microorganisms, that can prevent growth or kill bacteria.

Antibody

An immunoglobulin molecule synthesized on exposure to antigen, which can combine specifically with that antigen.

Antibody-dependent cellular cytotoxicity (ADCC)

The killing of antibody-coated target cells by cytotoxic cells with surface Fc receptors.

Antigen

Any foreign substance that can bind to specific lymphocyte receptors and so induce an immune response.

Antigen-presenting cells

Cells that can ingest, process, and present antigens to T cells. These cells express MHC class I or class II molecules on their surface.

Antigen processing

The series of events that degrade protein antigens into short peptides that bind to MHC molecules so that they can be recognized by T cells with appropriate TCRs.

Antigenic variation

The progressive changes in surface antigens exhibited by viruses, parasites, and some bacteria in order to evade immune destruction.

Antigenicity

The ability of a molecule to be recognized by an antibody or lymphocyte.

Antiglobulin

Antibody made against an immunoglobulin, usually by injecting immunoglobulin into an animal of another species.

Antiglobulin test

A technique for detecting the presence of nonagglutinating antibody on the surface of a particle.

Antiserum

Serum that contains specific antibodies. Synonymous with immune globulin.

Antitoxin

Antiserum directed against a toxin and used for passive immunization.

Anurans

An order of advanced amphibians that includes the frogs and toads.

Apoptosis

The controlled self-destruction of a cell; one form of programmed cell death.

Arthus reaction

Local inflammation due to a type III hypersensitivity reaction; it is induced by the injection of antigen into the skin of an immunized animal.

Asthma

A hypersensitivity disease characterized by a reduction in airway diameter, leading to difficulty in breathing (dyspnea).

Atopy

A genetic predisposition to become sensitized and produce IgE antibodies in response to allergens commonly occurring in the environment.

Attenuation

The reduction of virulence of an infectious agent.

Autoantibodies

Antibodies directed against epitopes on normal body tissues.

Autoantigen

A normal body component that acts as an antigen.

Autograft

A tissue or organ graft made between two sites within the same animal.

Autoimmune disease

Disease caused by an immune attack against an individual's own tissues.

Autoimmunity

An immune response against normal body components.

Autophagy

A process of cellular self-digestion by which cells can ingest and destroy intracellular microbes or damaged organelles.

B lymphocytes (B cells)

Lymphocytes that have undergone a period of processing in the bursa or its mammalian equivalent. They are responsible for antibody production.

Bacille Calmette-Guérin (BCG) vaccine

An attenuated strain of Mycobacterium bovis. This may be used as a specific vaccine or as a nonspecific immune stimulator.

Bacterin

A preparation of killed bacteria used for immunization.

Basophil

A polymorphonuclear cell that contains granules with a high avidity for basic dyes such as hematoxylin. It participates in type I hypersensitivity reactions.

Bence Jones protein

Immunoglobulin light chains found in the urine of patients with myelomas. They precipitate out of solution when the urine is warmed and redissolve at higher temperatures.

Benign tumor

A tumor that does not spread from its site of origin.

Blast cells

Actively dividing cells with large amounts of cytoplasm.

Blastogenesis

The stimulation of cell division.

Blocking antibody

A noncytotoxic, non–complement-activating antibody that, by coating cells, can protect them against immune destruction.

Blood groups

Antigens found on the surface of red blood cells. Their expression is inherited.

Bursectomy

Surgical removal of the bursa of Fabricius.

C-terminus

The end of a peptide chain with a free carboxyl ($\text{COO}^-$) group.

C3 convertases

Enzymes that can cleave native C3 into C3a and C3b fragments.

Capsid

The protein coat around a virus.

Carcinoma

A tumor originating from cells of epithelial origin.

Carrier

An immunogenic macromolecule to which a hapten may be bound, making the hapten immunogenic.

Cascade reactions

A linked series of enzyme reactions in which the products of one reaction catalyze a second reaction, and so forth.

Caspases

Proteolytic enzymes that play key roles in inflammation and apoptosis.

Cell-mediated cytotoxicity

The killing of target cells induced by contact with cytotoxic T cells, NK cells, or macrophages.

Cell-mediated immunity

A form of immune response mediated by T lymphocytes and macrophages; it can be conferred on an animal by adoptive transfer.

Cestodes

Parasitic tapeworms.

Checkpoint therapy

A cancer treatment that uses monoclonal antibodies to enhance T cell cytotoxicity and to destroy cancer cells.

Chemokine

A family of proinflammatory and chemotactic cytokines with a characteristic sequence of four cysteine residues. They regulate the emigration of leukocytes from blood into tissues.

Chemotaxis

The directed movement of cells under the influence of a chemical concentration gradient.

Chimera

An animal that contains cells from two or more genetically different individuals.

Chondrichthyes

The class that contains the cartilaginous fishes, including sharks, skates, and rays.

Chromosome translocation

A form of mutation in which portions of two chromosomes switch positions.

Chronic inflammation

Slowly developing or persistent inflammation characterized by tissue infiltration with macrophages and fibroblasts.

Class switch

The change in immunoglobulin class that occurs during the course of an immune response as a result of heavy chain gene rearrangement.

Classical complement pathway

The complement pathway triggered by activation of C1 by antigen-antibody complexes.

Clonal deletion

The elimination of self-reactive T cells in the thymus.

Clonal selection

The proliferation of specific lymphocyte clones in response to a specific epitope. The response is triggered through specific antigen-binding receptors.

Clonotype

A clone of B cells with the ability to bind a single epitope.

Cluster of differentiation (CD)

The set of monoclonal antibodies that recognize a single protein on a cell surface.

Coelomocyte

A phagocytic cell found in the coelomic cavity of invertebrates.

Collectins

A family of carbohydrate-binding lectins that depend on calcium for their adhesion.

Colostrum

The secretion that accumulates in the mammary gland in the last weeks of pregnancy. It is very rich in immunoglobulins.

Combined immunodeficiency

A deficiency in both the T cell– and B cell–mediated components of the immune system.

Commensal

Two species that live together and share resources.

Complement

A group of serum and cell surface proteins activated by factors such as the combination of antigen and antibody and results in the generation of enzyme cascades that have a variety of biological consequences.

Complementarity determining region

Those areas within the variable regions of antibodies and T cell antigen receptors that bind to antigens and determine the molecule's antigen-binding specificity.

Concanavalin A (Con A)

A lectin extracted from the jack bean that makes T cells divide.

Conglutinin

A bovine mannose-binding protein that also combines with C3b.

Corticosteroids

Steroid hormones released from the adrenal cortex that have profound effects on the immune system.

Co-stimulators

Molecules required to stimulate an antigen-sensitive cell simultaneously with antigen in order to initiate an effective immune response.