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37 Cards in this Set
- Front
- Back
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Define Innate Immunity.
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Defense system found in all animals; active immediately upon infection; same whether or not pathogen has already been encountered; includes barrier defenses; recognizes microbes by molecules and structure
-fast, generalized attack |
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Acquired immunity
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Only in vertebrates; develop slowly; response is enhanced by previous exposure; specificity
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Which defense system has a humoral response?
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acquired immunity
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Which defense system uses antimicrobial proteins?
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innate immunity
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Which defense system uses an inflammatory response?
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innate immunity
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Natural Killer cells are a part of what immune response?
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innate immunity
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What is a humoral response?
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a part of acquired immunity- antibodies defend against infection in body fluids
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What is a cell-mediated response?
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acquired immunity- cytotoxic lymphocytes defend against infection in body cells
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List the internal defenses of innate immunity.
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internal defenses-
-PHAGOCYTIC CELLS -ANTIMICROBIAL PROTEINS -INFLAMMATORY RESPONSE -NATURAL KILLER CELLS |
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______ acts by recognizing fragments of molecules characteristic of a set of pathogens. (ex: lipopolysaccharide=bacteria; double-stranded RNA=virus)
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TLR or Toll-Like Receptors
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Most abundant phagocytic cells?
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Neutrophils-attracted by signals from infected tissues
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Esinophils attack what?
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Low phagocytic activity, but important in defending against multicellular invaders --
parasites |
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What provides the innate defense against viral infection?
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Interferons (proteins); secreted by infected cells
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Complement system works how?
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30+ proteins that circulate until activated by the surfaces of microbes; work in a process to lysis invading cells
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What cells are histamines stored in?
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Mast cells
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Mast cells function in what response?
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Innate- inflammatory response
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Histamine causes blood vessels to (contract/dilate)?
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dilate
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How do Natural Killer cells recognize diseased cells?
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Following viral infection or cancer, cells may stop expressing class I MHC molecules on their surface
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What two types of cells make up lymphocytes (white blood cells)?
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B cells and T cells
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Lymphocytes that migrate to the thymus mature into what?
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T cells (Thymus)
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B cells mature where?
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the bone marrow
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Which proteins recruit and activate lymphocytes?
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cytokines (secreted by phagocytic cells of the innate immune system)
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What is an antigen?
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Any foreign molecule that is specifically recognized by lymphocytes eliciting a response
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How do B and T cells respond to antigens?
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By recognizing antigens using antigen-specific receptors embedded in their plasma membranes
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True or false: Each B or T cells has one specific antigen receptor on its surfece.
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False; each lymphocyte has about 100,000 antigen receptors on its surface
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What is the secreted soluble form of an antigen receptor?
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Immunoglobulin (antibody); secreted protein from a plasma cell
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What is an epitope?
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A small, accessible portion of the antigen that causes a response in lymphocytes.
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True or false: Each lymphocyte recognizes only one kind of epitope.
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True: All of the antigen receptors of a single lymphocyte are identical; lymphocytes display specificity for an epitope
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What is the structure of a B cell receptor?
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-Y-shaped
-4 polypeptide chains- 2 heavy chains, 2 light chains - disulfide bridges linking the chains together -transmembrane region anchors the receptor -short tail region in cytoplasm |
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What is the difference between an antibody and a B cell receptor?
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antibodies are secreted rather than membrane bound as in B cell receptors
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How do T cells and B cells differ in their immune responses?
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T cell receptors only bind to antigen fragments that are still attached to the host cell; B cell receptors only bind to intact antigens (free or expressed)
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What is the name of the complex that ]binds antigen fragments to molecules inside the cell? This binding results in what?
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major histocompatibility complex (MHC); this results in antigen presentation
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What cell recognizes antigen presentation?
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T cells
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What are the two classes of MHC molecules are what characterizes each?
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Class I MHC- on almost all nucleated cells. Bind to peptide fragments of antigens and then synthesizes foreign antigens for display
Class II MHC- made by dendritic cells, macrophages, and B cells (antigen presenting cells) |
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3 characteristics of acquired immunity
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1. tremendous diversity
2. lack of reactivity against own cells 3. previous exposure results in a stronger and more rapid response |
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What is a cytotoxic T cell?
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Subgroup of T cells responsible for recognizing bound antigen fragments displayed by Class I MHC molecules
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What does a helper T cell do?
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A group of T cells that assist B cells and Cytotoxic T cells; recognizes antigen fragments presented by Class II MHC molecules
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