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50 Cards in this Set
- Front
- Back
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what is the immune system |
a defense mechanism that requires cells and molecules to act together, generating an immune response, to protect a host from a disease causing organism (antigen) |
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what two process are needed in order for an immune response to be effective |
-recognition of antigen -effector response (neutralizes or destroys pathogen) |
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antigen |
pathogen or substance that elicits an immune response |
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innate immune response |
-first line of defense -nonspecific response -response does not change if repeatedly exposed to the same antigen (no memory) -primitive system only |
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4 defense barriers of innate immune system |
-anatomical barriers to infection -physiological barriers to infection -phagocytosis -inflammatory response |
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anatomical barriers |
-skin -mucosal membranes |
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physiological barriers |
-acidic pH -enzymes and binding proteins -antimicrobial peptides
produce protective substances |
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phagocytosis |
engulfment and internalization of materials such as microbes for their destruction |
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inflammatory response |
chemoattractants act as hormones which draws attention to the inflamed site
vasoactive factors cause capillaries to dilate which increases diameter of blood vessels which increases permeability
neutrophils and other phagocytes travel to site of inflammation and destroy the bacteria |
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adaptive immune response |
-responses are specific to antigen it is important that the right response is selected, selecting the wrong response can be fatal -requires cooperation between -lymphocytes -antigen presenting cells -soluble mediators |
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3 cell types found in blood |
-red blood cells -white blood cells (most important in an immune response) -platelets |
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soluble mediators |
-cytokines -soluble antibody |
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importance of understanding how immune system works |
-exploit it to prevent infection (vaccines) -exploit it to treat illness -provide safer organ and tissue transplants |
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the advantage of an antigen being opsonized |
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how does the immune system destroy/neutralize antigens |
n/a |
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where do cells that are destined to become immune cells originate |
bone marrow |
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humoral response |
involves B cells |
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cell mediated response |
involves T cells |
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what must a cell do in order to be called an antigen presenting cell |
process an antigen and present it
process = chopping antigen up presenting = MHC is attached to a piece of antigen |
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t helper cells |
CD4 marker = adhesion molecule that binds to MHC class II |
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cytotoxic t cells |
CD8 marker = adhesion molecule that binds to MHC class I |
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b cells |
antibodies -surface -soluble
5 classes of antibodies A G M D E |
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what are the various functions of surface markers? are the number and kinds of receptors thats you find on the cell surface fixed? |
function -antigen recognition -antigen presentation -cell to cell communication -receptors for soluble mediators of immunity
~ receptors are both shared and unique to the cells |
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primary lymphoid tissues/organs |
thymus = T cell development bone marrow = B cell development |
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secondary lymphoid tissues/organs |
spleen = trap blood born antigens lymph nodes = trap antigens found in lymphatic fluid and bodily tissues
MALT --> deliver antigen from intestinal spaces to lymphoid cells in the gut wall GALT CALT NALT |
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tertiary lymphoid tissues/organs |
lungs liver brain |
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what must lymphoid progenitor cells do in order to develop into a specific type of immune cell |
relocate |
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if hematopoesis can not occur what will happen |
leukemia will develop -myeloid leukemia = not producing myeloid cells -lymphoid leukemia = not producing lymphoid cells |
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immunocompetence |
cell has required antigen specificity
~all B cells in body have different antigen receptors that recognize different antigens ~T cell receptors don't just bind to any piece of antigen received, but to pieces of antigen familiar to the receptor |
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selection process thymocytes undergo in the thymus |
positive and negative selection
double positive = both CD4 & CD8 present single positive = only one receptor present (thymocyte) ~occurs in cortex of thymus
negative = cells can recognize MHC
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selection process for immature B cells |
only negative selection
~if the antibody recognizes non-self antigens then the cell can mature |
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why is it important that your immune cells continue to circulate throughout your body |
by moving into the tissues from the blood, lymphocytes constantly scanning for antigens to which it can respond |
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using morphology to distinguish dendritic cells and granulocytes |
dendritic cells have pseudopodia while granulocytes have a more round shape |
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soluble vs surface antibody |
soluble antibodies are secreted into the blood and tissue fluids
surface antibodies facilitates the activation of B cells |
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antibody |
also known as an immunoglobulin used by the immune system to identify and neutralize foreign objects such as bacteria and viruses (antigens) |
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5 classes of antibody |
IgA - alpha IgG - gamma IgE - sigma IgD - delta IgM - mu |
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IgG |
4 subclasses that differ in the number of interchain disulfide bonds
cross placenta = confer passive immunity to newborn
some animals (i.e. pigs)
the groups of receptors CD64 CD32 CD16 ~specific for the Fc region of antibody
~there is more IgG antibody in human blood than any other antibody |
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IgM |
membrane from = monomeric
soluble form = pentamer ~confined mostly to the intravascular system (because of its size it cannot travel)
predominant Ig of primary immune response
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IgA |
two subclasses = IgA1 & IgA2
monomer = IgA dimer = sIgA --> secretory form
~secretory component allows dimer to go into bodily secretions (i.e. tears, mucus, saliva)
predominant Ig in external secretions
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IgD |
surface form is more prevalent than soluble form
biological function is unknown |
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IgE |
associated with intermediate hypersensitivity reactions (abnormal reactions)
binds to Fc region on mast cells/basophils -->induces degranulation-->allergic response
high concentrations are produced in response to infection with intestinal parasites |
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what is an effector response |
immune response that either destroys or neutralizes antigen (Fc binding region) |
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what makes a good antigen |
one that is recognized and effectively eliminated |
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epitope/antigenic determinants |
immunologically active regions on an antigen that are recognized as non-self |
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why do B cells only recognize accessible epitopes |
surface antibodies of B cells bind to intact/native antigens |
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why is it not important where the epitopes are located when it comes to T cell activation |
T cells can recognize any piece of the antigen as long as it has been processed and presented |
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how does an antibody recognize and bind to an antigen |
variable light and variable heavy regions of the antibody each contain 3 complementary determining regions that are high in amino acid variability ~CDR regions are the actual regions binding to the antigen |
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what types of bonds are formed when an antibody binds to an antigen |
-hydrogen bonds -ionic bonds -hydrophobic interactions -van der waals |
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affinity vs avidity |
affinity = strength of the non-covalent interactions at one site
avidity = strength of the non-covalent interactions at multiple sites |
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cross-reactive antibodies |
process that occurs when an antibody elicited by one antigen cross reacts with an unrelated antigen
benefits = taking down two or more antigens with the same antibody while only spending energy on making one antibody
disadvantages = in strep throat, there are epitopes in the antigen that are recognized in the skeletal muscle and cardiac muscles |
