Immune System
Campbell Biology 7th
Chapter 43
Chapter 43
Terms
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- CD8
- a surface protein on cytotoxic T cells that binds the cell to a target cell
- T CELL
- a lymphocyte that matures in the thymus; it will start cell-mediated immunity when it encouters an anitgen
- ANTIGEN PRESENTATION
- the process by which an MHC molecule binds to a fragment of an intracellular protein antigen and carries it to the cell surface, where it can be recognized by a T cell
- CD4
- a surface protein on helper T cells that binds the class II MHC molecule
- ANTIGEN-PRESENTING CELL
- dendretic cell, macrophase, B cell; dislays internalized antigens to helper T cells
- LIGHT CHAIN
- a polypeptide chain that is made of a variable region that contributes to the antigen-binding site and a constant region
- EOSINOPHIL
- attacks multicellular parasites; secretes enzymes that attack the parasite rather than digests it; not too common
- EFFECTOR CELL
- a muscle or gland cell that resonds to stimuli ; short-lived daughter cell of lymphocytes
- HELPER T CELL
- a cell that responds to peptide antigens displayed on antigen-presenting cells and stimulates the activation of nearby B cells and cytotoxic T cells
- NEUTROPHIL
- 60-70% of all white blood cells; self-destruct when it performs phagocytosis
- INNATE IMMUNITY
- unspecific immunity that is present at birth (skin, mucous, chemical defenses)
- MEMORY CELL
- long-lived daughter cell of lymphocytes; has receptors that are specific for the antigen that caused the mother cell to clone itself
- CYTOKINE
- secreted by macrophages and dendritic cells; activates lymphocytes and other cells
- CHEMOKINE
- a small protein that directs the migration of phagocytes toward an infected cell and signals them to increase productionf of microbe-killing compounds; part of the inflammatory response
- HISTAMINE
- a chemical that is part of the inflammatory response; dilates blood vessels so that more blood can flow to the injured site (swelling)
- INFLAMMATORY RESPONSE
- damaged tissue will cause many chemical signals to be released
- ANTIGEN
- any foreign molecule that lymphocytes recognize and respond to
- ANTIBODY
- produced by a B-lymphocyte in the humoral response; is a defensive protein that binds to microbes and mark them for elimination
- PHAGOCYTOSIS
- ingestion of microorganisms by certain white blood cells (phagocytes) that produce antimocrobial proteins and start inflammation
- ACQUIRED IMMUNITY
- specific immunity that develops after expsoure to foreign substances
- PLASMA CELL
- generated by B cells; an antibody-secreting effector B cell
- NATURAL KILLER CELL
- an innate defense cell of vertebrates; it patrols the body and attacks virus-infected or cancer cells; it has receptors that can recognize general features on the surfaces of its targets; kills cells by apoptosis
- INTERFERON
- protein secreted by cells infected by viruses; it initiates an innate response by nearby cells so that they will produce substances that stop viral reproduction
- MAST CELL
- a cell that stores histamine; located in connective tissues
- B LYMPHOCYTE
- a lymphocyte that matures in the bone marrow; after encountering an antigen, it will differentiate into antibody-secreting plasma cells (effector cells of humoral immunity)
- LYSOZYME
- an enzyme that digests cell walls of bacteria; present in saliva, tears, mucous secretions in the upper respiratory tract and eyes
- ANTIGEN RECEPTOR
- a surface protein on a B/T lymphocyte that starts acquired immune responses
- SECONDARY IMMUNE RESPONSE
- a fast immune response that appears in 2 - 7 days
- T CELL RECEPTOR
- a receptor that has 2 different polypeptide chains (a and B) linked by a disulfide bridge; recognizes fragments of antigens boudn to MHC molecules
- CLONAL SELECTION
- antigens bind to specific receptors, causing a fraction of lymphocytes to clone themselves
- B CELL RECEPTOR
- Y-shaped receptor that is made of 4 polypeptide chains: 2 identical heavy chains and 2 light chains linked by disulfide bridges; recognizes intact antigens
- IMMUNOGLOBULIN
- a secreted antibody that is similar to B-cell receptors that isn't bound to a transmembrane
- MACROPHAGE
- large, long-lived cell that develops from a monocyte; stays in the sleep and lymph nodes
- APOPTOSIS
- programmed cell death
- MAJOR HISTOCOMPATIBILITY COMPLEX
- A family of genes that encode a large set of cell surface proteins called MHC molecules. Class I and class II MHC molecules function in antigen presentation to T cells. Foreign MHC molecules on transplanted tissue can trigger T cell responses that may lead to rejection of the transplant.
- HEAVY CHAIN
- a polypeptide chain that is made of a variable region that contributes to the antigen-binding site and a constant region
- PRIMARY IMMUNE RESPONSE
- the acquired immune response to an antigen, which appears after a lag of about 10 to 17 days
- CELL-MEDIATED IMMUNTE RESPONSE
- acquired immune response where cytotoxic T cells are cloned and destroy target cells
- CYTOTOXIC T CELL
- a lymphocyte that, when activated, kills infected cells, cancer cells, and transplanted cells; can recognize Class I MHC molecules
- THYMUS
- a gland in the thoracic cavity above the heart
- DENDRITIC CELL
- ingests microbes but focuses more on acquired immunity
- CELL-MEDIATED RESPONSE
- cytotoxic lymphocytes directly destroy infected body cells, cancer cells, or foreign tissue
- HUMORAL IMMUNE RESPONSE
- acquired immune response that involves the activation of B cells and that leads to the production of antibodies in body fluids
- LYMPHOCYTE
- white blood cell that can produce two types of immune responses
- MONOCYTE
- 5% of circulating white blood cells; turns into a macrophage
- COMPLEMENT SYSTEM
- a system made of 30 serum antimicrobial proteins that, when activated, will lyse pathogenic cells
- EPITOPE
- a small, accessible region of an antigen to which an antigen receptor or antibody binds; also called an antigenic determinant