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why is adaptive immune response important?
- protects us from many infections
- has memory so we are not infected by the same pathogen a 2nd time (this is why vaccinations work)
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Adaptive immune response is the 2nd level of immunity. what does it involve?
- it involves lympcytes
- it is a response to specific antigens
- it is exraordinarily specific
- it can adapt to any infection
- it has memory (life long immunity)
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what are the 2 types of respnses
- innate- prerequistie for adaptive immune response
- adaptive immune response (2 types)
- -humoral- production of antibodies
- -cellular- killing and regulation og infected cells
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define humoral and cellular responses.
- humoral:
- carried out by B lymphocytes
- Responsible for production of antibodies
- activation of B cells usually requires help from T cells
- some B cells proliferate and differentiate into plasama cells (produce massive amounts antibody)
- Some B cells become memory cells
- Cellular:
- carried out by T lymphocytes (cytotoxic T and helper T cells)
- responsible for killing and regulation of infected cells
- T cells that have not seen antigen are considered naive, but after encountering antigen, both T cell types become armed effector T cells
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where is the lymphatic system?
- cover the entire body
- lymphocytes and lymphoid structures
- adaptive immune response is associated w/ it
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what is the function of dendritic cells?
- most important cells in the adaptive immune response
- because:
- -have enormous surface areas- grabs antigen
- -take up and process antigens
- -present antigens to T cells
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what is a clonal selection? fig 16.7
- which some lymphocytes are destroyed and others are allowed to mature. this selection process takes place in the bone marrow for B cells and in thymus for T cells
- how the immune system responds to infection
- takes place in the bone marrow for B cells and in the thymus for T cells
- lymphocytes that remain after clnal deletion maure
- each is specific for nonself antigen
- if an antigen is encountered, the lymphocye is activate (begins to divide and proliferate. It forms a clone of cells specific for one antigen)
- lymphocytes that never encouter antigen eventually die
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what are the 3 important points about clonal selection?
- it generates a vast # of different antigen receptors
- each receptor is specific for a different antigen
- all progeny of that lymphocyte will have the exact same receptor
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what do lymphid precursos T and B cells give rise to?
- T cells- Cytotoxic (Tc) and Helper T cells
- B cells- differentiate into plasma cells
- NKC
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what are the 2 types of helper T cells? what do they activate?
- 2 types of helper T cells-
- -Th1
- -Th2
- Activate the B cells and macrophages
- T cells are naive until they encouter antigens (co-stimulatory signals must be present)
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when B cells and T cells mature, they acuire specific antigen receptors...
- B cell receptor is an immunoglobulin molecule (2 antigen binding sites)
- T cell receptor is similar to Ig (only 1 antigen binding site)
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where do B and T cells originate form? where do T cells mature? Where do B cells mature? then what do they do?
- B and T cells originate in bone marrow
- T cells mature in the thymus gland (thymus atrophies at puberty, T cells are long lived, maturation requires specific signals)
- B cells mature int he bone marrow
- when mature, both circulate through the blood and tissues looking for antigens
- maturation requires specific signals
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lymphoid tissues, B cells. Tell me when B cells die?
- most of them die when they reach the peripheral tissue
- they are constanty replaced and therefore the # remains constant
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what are the 3 functions of antibodies?
- neutralization: antibodies neutralize toxins and virsuses and also prevent bacterial attachment ("staying in" requirment for infection)
- opsonization: antibodies facilitate the uptake of pathogens by phagocytic cells
- complement activation system: antibodies activate the classical pathway of the complement system
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name the 5 antibody isotypes?
IgM, IgG, IgA, IgE, IgD
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whats IgM?
- first antibody to be produced in a humoral response
- pentamer structure
- usually found in blood
- excellent activator of the complement system
- primary response to bloodborne pahtogens
- found in pleural spaces (protects enviro pathogens)
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what is IgA?
- principle antivody in secretions
- found in respiratory and digestive tract
- it is not very effective in activating the complement system
- found in colostrum (transfered from mom to child. protects against newly encountered bacteria)
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what is IgG?
- principal isotope in the blood and exracllular fluid
- very effective for opsionization and activation of complement
- newborns recieve (can cross the placenta)
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what is IgE?
- found in low levles in the blood and extracellular fluids
- binds tightly to mast cells just below the skin and mucosa
- it is also found along the blood vessels in connective tissue
- after antigen binding, powerful chemical mediators are released (causing coughing, sneezing, vomitting)
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what is IgD?
- found in very small amounts in the blood
- it is found on the surface of B cells
- has no known function in serum
- it is involved as an early antigen receptor
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Tell me about T cell response
- cellular immune cell response is generated by T cells (cytotoxic and helper T cells)
- T cells that have not seen antigen are considered to be naive
- after encountering antigen, both types become armed effector T cells
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what are the 3 classes of armed effector T cells
- cytotoxic
- Th1 helper- provide activation signals for macrophage
- Th2 helper
- most of these move into the blood when they are activated
- cytotoxins are released by cytotoxic T cells
- cytokines are released by helper T cells
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what is one of the most improtant properties of adaptive immune response? what form can it be seen in? what is the memory due to? what due interlukins help do?
- immunological memory is most important
- seen in both T and B cells and is produced after infection or vacination
- memory is due to persistent population
- Interleukins help maintain the memory T cell pop
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when does innate and adaptive response take place?
- innate= early stages of infection
- adaptive= few days after 1st exposure to antigen
- once the pathogen is estab. only adaptive can rid of it
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explain the immunity to infection
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explain adaptive response
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