Micro Exam 3: Specific Immunity – Flashcards
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| What are the 2 components of specific immunity? |
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| What are is the term used for molecules that stimulate and immune response? |
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| antigens |
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| what are haptens? |
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| substances which are too small by themselves to elicit an immune response but may when bound to larger molecules |
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| what is an epitope? |
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| molecular structure on an antigen that an antibody interacts with. one antigen may have many. |
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| True or false: some antigens can only be recognized after having been processed by T cells. |
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| True |
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| What are antibodies? |
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AKA immunoglobulins they are proteins produced by the body to bind to antigens |
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| Describe the structure of an antibody |
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| Where might antigens be? |
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| on the surface of organisms, substances in serum (toxins or visuses) |
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| can antibodies always neutralize toxins and viruses? |
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| no; may or may not be able to |
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| Approximately how many different antibody specificities are there for antigens? |
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| 106-108 |
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| What are the three ways that antibodies participate in host defenses? |
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| Which antibodies are in charge of neutralization? |
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| IgG, IgM and IgA are able to bind and prevent them from reaching target receptors |
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| How does opsonization occur? |
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| antibodies or complement (C3b) coat an antigen which signals it as foreign to phagocytes who then ingest and destroy them |
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| complement activation is via which pathway in specific immunity? what does it occur after? |
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| classical pathway; occurs after antigen-antibody binding |
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| what does activation of the classical pathway require? |
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| Why is only one molecule of IgM needed to activate the classical pathway? |
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| because of its pentameric structure |
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| Define polyclonal response. |
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| a mixture of antibodies of a class produced to different epitopes of the antigen |
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| what is monoclonal antibodies? |
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preparation of pure antibodies of single type all directed at same epitope - normally produced artificially; not normal response but in malignancy of B cells |
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| Is polyclonal response or monoclonal antibodies a more normal response? Are both naturally occuring? |
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polyclonal is normal response monoclonal is artificial unless B cell malignancy |
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| what is the term used to describe the strength of binding between an antibody and an antigen? |
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| affinity |
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| Does affinity of an antibody and antigen ever change? |
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| often increases with second or more exposures to antigen |
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| What are the different classes of antibodies? Which are less plentiful? |
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IgM, IgG, IgA IgE, IgD = less plentiful |
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| What are the heavy chain structures of IgG, IgA, IgE, IgD, IgM? |
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attach by disulfide bond to joining chain |
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| What is the first antibody produced in response to a first infection? |
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| IgM |
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| What antibody occurs as a 5 units attached; how does this affect is movement? |
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| IgM; does not get into tissue from blood or cross placenta (large molecule) |
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| Does complement bind well to IgM? |
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| Yes! |
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| What is the most plentiful immunoglobulin? |
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| IgG |
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| What is produced after IgM in an infection? What is this process called and what does it do? |
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IgG; called "class switching" - IgG antibody produced by cell has same specificity for antigen as IgM it replaces |
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| When is IgG predominantly produced? What is this response called? |
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| when exposure to agent occurs in second infection; called a boosting response |
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| What controls IgG production? |
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| T cells |
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| What does IgG do in terms of complement; can it penetrate tissues? |
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binds to complement (fixes complement), attracts phagocytes, and opsonizes well - penetrates tissue and crosses placenta |
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| Secondary response to an immunogenic stimulas has... |
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| What is an anamnestic response? What cells are involved? How is the affinity increased? |
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Secondary response; affinity maturation 10 to 100 fold increase IgG memory cells |
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In what forms does IgA occur? What form is secretory IgA? Where is it found? What controls the production of IgA? |
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| Which immunoglobulins activities are antiparasitic? What other activities does this immunoglobulin have? |
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| IgE; also involved in hypersensitivity reactions |
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| Where is IgD found? |
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| as a receptor on B cell surface antigens |
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| What are the 3 groups of blood stem cells in bone marrow? |
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| What are the cells produced by myeloid stem cells? Which are involved in phagocytosis, inflammation and clotting (an inflammation)? |
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| List the types of leukocytes. |
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| What are the most common WBC? What do they do? How long do they live? |
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Polymorphonuclear leukocytes (neutrophils; PMN) ; white blood cells able to phagocytose invaders short lived circulate in blood and enter tissue (gather at site of infection) = pus
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| Pus is largely made up of what cells? |
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WBC's; Polymorphonuclear leukocytes (PMNs) |
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Which white blood cells are anti-parasitic? How did they get their name? |
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| eosinophils; contain granules that stain red with dye eosin (may also increase in hypersensitivity states - ex. asthma) |
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| What cells are involved in hypersensitivity reactions? |
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| basophils (and maybe eosinophils) |
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| What are monocytes? |
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| WBC that circulate until stimulated to differentiate to macrophages or on of family of phagocytes (dendritic cells) found in various organs in body |
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| Compare Macrophages and PMN's |
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| macrophages are larger and longer lived (found in tissues) |
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| what are macrophages able to do? |
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| What are dendritic cells descended from? |
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| monocytes or lymphocyte cell lines (like octopuses) |
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| Where are dendritic cells distributed (what form?)? What are they good at doing? What do the immature and mature do? |
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| What do B cells differentiate into? Where does this occur? |
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| differentiate to plasma cells or memory cells in bone marrow of mammals |
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| What do plasma cells come from and what are they? |
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come from B cell differentiation in bone marrow they are antibody factories
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| What do memory cells do? |
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| circulate and are primed to produce a specific antibody if they come in contact with the apropriate antigen |
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| What is the secondary lymphoid organ? |
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| spleen |
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| During development, B cells are produced that do what? What is each B cells membrane coated with? What happens when antigens binds to this? What is that process called? |
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each recognize a specific antigen (so many B cells that a wide range of antigens can be recognized)
membrane coated with particular antibody that cell produces When antigen binds to antibody = stimulates cell to divide and increase in number called "clonal expansion" |
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| Where do T cells develop? What do they control and how? |
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| Do NK cells express CD-4 or CD-8? What kind of cell are they? |
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| no, they are T cells |
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| True or false: some T cells and B lymphocytes develope into memory cells. |
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| true |
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| What do CD4 or "T Helper cells" do? What do they differentiate into? |
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activate and control immune response
respond to signal of cell presenting antigen by differentiating into: TH1 or TH2 |
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| What T cells promote local response with inflammation and are good at handling intracellular pathogens (eg. viruses, mycobacteria, fungi) |
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| CD4 - TH1 |
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| What T cells promote antibody production and memory cells? |
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| CD-4; TH2 |
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| Does TH1 or TH2 occur first? Which is systemic? |
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| TH1 occurs first; TH2 is systemic |
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| What do CD8 (suppressor T cells) do? What do they differentiate into? |
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| What can suppress helper T cell function? What does it use? |
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| CD8 cells; by using inhibitory cytokines |
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What are natural killer cells? What are they used to kill? |
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| large granular lymphocytes that contain granules of cytotoxic material (used to kill virally infected cells and tumor cells) |
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| How are NK cells distinct from CD8 T cells? |
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| they have Fc receptors to allow them to detect cells coated with antibody, which they then destroy |
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| What are the most common types of cytokines? |
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| interleukins; also tumor necrosis factors |
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| What produces cytokines? What do they do? |
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produced by cells - bring about differentiation of cells - cause activation of phagocytic cells and lymphocytes - influence inflammation - influence cell mediated response and antibody response |
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| How are cytokines usually produced? Do they always act the same? What is an important source of cytokines? |
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| What must happen before T cells can act upon antigens? What plays an important role in this? |
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| What MHC is used in tissue typing to determine if transplants will be compatible (HLA typing)? |
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| MHC I |
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| What MHC is found on all cells and is essential for recognition of "self"? |
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| MHC I |
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| What MHC is found on monocytes, macrophages, B cells, dendritic cells and phagocytic cells related to macrophages found in tissue? |
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| MHC II |
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| MHC I presents antigens to what cells? MHC II presents antigens to what cell? |
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MHC I = CD 8 MHC II = CD 4 |
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| Cells important to the immune system originate where? What organ systems do they form? |
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| originate in bone marrow and some in thymus; primary lymphoid organs |
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| What are the 2 primary organs of the immune system and why? |
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| Why are B cells called B cells? |
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| because of the Bursa of Fabricius in birds |
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| What are the secondary organs of the immune system? |
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major sites of interaction with antigens - lymph nodes - tonsilds and adenoids - spleen - MALT or GALT |
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| What organ is located within the mediastinum, superior and anterior to the heart, made up of glandular tissue and is large during infancy? |
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| thymus |
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| Lymphocytes are based in what? |
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| secondary lympoid organs |
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| What acts as a "super" lymph node? What does it do? What is of particular importance? |
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Spleen screens out old or infected blood cells, encapsulated bacteria and viruses particularly important at removing encapsulated organisms |
