Life 42- Immunology Flashcards
T cell
A type of lymphocyte involved in the cellular immune response. The final stages of its development occur in the thymus gland
Pathogen
An organism that causes disease
T-helper cell
Type of T cell that stimulates events in both the cellular and humoral immune responses by binding to the antigen on an antigen-presenting cell; target of the HIV-I virus, the agent of AIDS
Cytokine
A regulatory protein made by immune system cells that affects other target cells in the immune system
Lymphocyte
One of the two major classes of white blood cells; includes T cells, B cells, and other cell types important in the immune system
Monoclonal antibody
Antibody produced in the laboratory from a clone of hybridoma cells, each off which produces the same specific antibody
Nonspecific defences
Immunologic responses directed against any invading agent without reacting to specific antigens
Immediate hypersensitivity
A rapid, extensive overreaction of the immune system against an allergen, resulting in the release of large amounts of histamine
Delayed hypersensitivity
An increased immune reaction against an antigen that does not appear for 1-2 days after exposure.
Regulatory T cells
Class of T cells that mediates tolerance to self antigens
Inflammation
A nonspecific defence against pathogens; characterised by redness, swelling, pain, and increased temperature.
Constant region
The portion of an immunoglobulin molecule whose amino acid composition determines its class and does not vary among immunoglobulins in the class
Lysozyme
An enzyme in saliva, tear, and nasal secretion that hydrolyses bacterial cell walls
Colonial selection
Mechanism by which exposure to antigen results in the activation of selected T or B cell clones, resulting in an immune response.
Antigenic determinant
The specific region of an antigen that is recognised and bound by a specific antibody
Normal flora
Microorganisms that normally live and reproduce on or in the body without causing disease, and which form a nonspecific defence against pathogens by competing with them for space an nutrients.
Lymph
A fluid derived from blood and other tissues that accumulates in intercellular spaces throughout the body and is returned to the blood by the lymphatic system
Complement system
A group of eleven proteins that play a role in some reactions of the immune system but are not immunoglobulins
Defensin
A type of protein made by phagocytes that kills bacteria and enveloped viruses by insertion into their plasma membranes
Vaccination
Injection of virus or bacteria or their proteins into the body, to induce immunisation. The injected material is usually attenuated (weakened) before injection
Plasma cell
An antibody-secreting cell that develops from a B cell; the effector cell of the humoral immune system
Major Histocompatibility complex (MHC)
A complex of linked genes, with multiple alleles, that control a number of cell surface antigens that identify self and can lead to graft rejection
Blood plasma
The liquid portion of blood, in which blood cells and other particulates are suspended
White blood cells
Cells in the blood plasma that play defensive roles in the immune system
Interferon
A glycoproteins produced by virus-infected animal cells; increases the resistance of neighbouring cells to the virus
Human immunodeficiency virus (HIV)
The retrovirus that causes acquired immune deficiency syndrome (AIDS)
Allergic reaction
An overreaction of the immune system to amounts of an antigen that do not affect most people; often involves IgE antibodies
Memory cells
Long-lived lymphocytes produced by exposure to antigen. They persist in the body and are able to mount a rapid response to subsequent exposure to the antigen
Prostaglandin
Any of a group of specialised lipids with hormone-like functions. It is not clear that they act at any considerable distance from the site of their production.
Natural killer cell
A type of lymphocyte that attacks virus-infected cells and some tumour cells as well as antibody-labelled target cells
Primary immune response
The first response of the immune system to an antigen, involving recognition by lymphocytes and the production of effector cells and memory cells
Cytotoxic T cells
Cells of the cellular immune system that recognise and directly eliminate virus-infected cells
Antigen
Any substance that stimulates the production of an antibody or antibodies in the body of a vertebrate
B cell
A type of lymphocyte involved in the humoral immune response of vertebrates. Upon recognising an antigen pic determinant, it develops into a plasma cell, which secretes an antibody
Autoimmunity
An immune response by an organism to its own molecules or cells
Humoral immune response
The response of the immune system mediated by B cells that produces circulating antibodies active against extracellular bacterial and viral infections
Specific defences
Defensive reactions of the vertebrate immune system that are based on the reaction of an antibody to a specific antigen
Clonal deletion
Inactivation of destruction of lymphocyte clones that would produce immune reactions against the animal’s own body
Secondary immune response
A rapid and intense response to a second or subsequent exposure to an antigen, initiated by memory cells
Cellular immune response
Immune system response mediated by T cells and directed against parasites, fungi, intracellular viruses, and foreign tissues (grafts)
Hybridoma
A cell produced by the fusion of an antibody-producing cell with a myeloma (tumour) cell; it produces monoclonal antibodies
Immunoglobulins
A class of protein containing a tetramer consisting of four polypeptide chains- two identical light chains and two identical heavy chains- held together by disulfide bonds; active as receptors and effects in the immune system
Class switching
The process whereby a plasma cell changes the class of immunoglobulin that it synthesises by changing the DNA region coding for the C segment
Acquired immune deficiency syndrome (AIDS)
A condition caused by human immunodeficiency virus in which the body’s T-helper cells are reduced, leaving the victim subject to opportunistic diseases
Lymph node
A specialised structure in the vessels of the lymphatic system, containing lymphocytes, which encounter and respond to foreign cells and molecules in the lymph as it passes through the vessels.
Variable region
The portion of an immunoglobulin molecule or T-cell receptor that includes the antigen-binding site and is responsible for this specificity
Class 1 MHC molecules
Cell surface proteins that participate in the cellular immune response directed against virus-infected cells
Histamine
A substance released by damages riddle or by mast cells in response to allergens; increases vascular permeability, leading to edema (swelling)
Mast cells
Cells, typically found in connective tissue, that release histamine in response to tissue damage.
T cell receptors
A protein on the surface of a T cell that recognises the antigenic determinant for which the cell is specific
Effector cells
A cell responsible for the effector phase of the immune response.
Antibody
One of the myriad proteins produced by the immune system that specifically binds to a foreign substance in blood or other tissue fluids and initiates it removal from the body
Class 2 MHC molecules
Cell surface proteins that participates in the cell-cell interactions (of T-helper cells, macrophages, and B cells) of the humoral immune response
Tumour necrosis factor
A family of cytokines that causes cell death and is involved in inflammation
Immunological memory
The capacity to more rapidly and massively respond to a second exposure to an antigen than occurred on first exposure.
Macrophage
Phagocyte that engulfs pathogens by endocytosis
Phagocyte
One of two major classes of white blood cells; one of the nonspecific defences of animals; ingests invading microorganisms
