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SGU: Immunology Set 1
Terms in this set (167)
body defenses that protect against disease
What is immunity?
physical barriers, mechanical processes, innate immunity, aquired immunity, passive immunity
What are the types of immunity?
cough, sneeze, vomit, diarrhea
What are some examples of mechanical processes that protect against disease?
neutrophils, macrophages and NK cells
What cells are part of innate immunity and are immediately available when needed
inflammation: increased blood flow and accumulation of cells to the area of microbial invasion
What occurs during an innate defense process?
How quickly does the innate immune process happen?
NO! also need acquired immunity
Is innate immunity enough to survive?
acquired immunity b/c it recognizes specific foreign bodies, has a memory and is able to differentiate self from non-self
What is considered the "smart" immunity? Why?
so it can respond more quickly the next time
**initial response take time
Why is it important for the acquired immunity to have memory?
pathogenic microbes, allergens or tissue graft for non-identical twin
What does the acquired immunity respond to?
molecules of foreign invaders that are recognized by and stimulate lymphocytes
What are antigens?
natural exposure or artificially (like by vaccines)
How would an animal encounter antigens?
B-lymphocyte come from what type of immunity?
What type of immunity targets extracellular bacteria?
T-lymphocytes come from what type of immunity?
What type of immunity targets intracellular pathogens?
What are some examples of passive immunity?
local infusion at wound site with additional amount given IM at another site away from wound
How is HRIG (human rabies immune globulin) given?
4 vaccines (days 0,3,7 and 14) plus HRIG
How many rabies vax would a person get post-exposure if they were not previously vaccinated?
2 vax on days 0 and 3. **NO HRIG!
How many rabies vax would a person get post-exposure if they were previously vaccinated?
hypersensitivities, autoimmunity, immunodeficencies, and neoplasia of immune system
What are some disregulations of the immune system?
innate immune mechanisms
What is the 1st line of defense after a microbial invasion?
What is the most important innate immune response?
What type of cells recognize and destroy infected cells of the animals body?
enzymes, defensins, interferons, complement proteins
What are some soluble defense factors?
coat microbes and help phagocytosis by other cells
What do opsonins do?
enzymes and defensins
What are the primary granules of the innate immune system?
lysozymes, lactoferrin and collagenases
What are the secondary granules of the innate immune system?
What are the major phagocytes that have high numbers in circulation?
6-10hr up to a few days
How long is the lifespan of a neutrophil?
death of the neutrophil
Phagocytosis by neutrophils leads to ______
Dying neutrophils attract ______
What can cause neutrophilia?
adhere to endothelium
How do neutrophils exist in MP?
surface protein molecules
What is needed for a neutrophil to be able to attach to endothelium?
integrins on neutrophils bind inflamed endothelial cells
How do integrins help neutrophils exit vascular system in order to enter tissues?
chemotxic cytokines; help mediate inflammatory response
What are chemokines and what do they do?
chemotaxis, adgerence to microbe, ingestion of microbe and destruction of microbe
What are the steps of phagocytosis?
receptors for complement proteins and for the Fc part of antibodies
What type of receptors are found on neutrophils?
important to fascilitate adherence of microbes and fascilitate phagocytosis
Why is it important for neutrophils to be able to bind complement proteins and antibodies?
respiratory burst (oxygen-dependent killing within phagosome)
What type of destruction requires oxygen to kill microbes?
low pH is toxic to most microbes; lysosomal enzymes enter the phagosome during fusion of lysosome with phagosome --> destroys bacterial cell wall
How are microbes destroyed using oxygen-independent killing?
becomes resistant to lysosomal content or inhibit phagolysosome fusion
How can pathogens survive inside macrophages?
mycobacterium bovis, rhodococcus equi, brucella abortus, listeria monocytogenes and salmonella typhimurium
What are some examples of pathogens that can survive inside macrophages?
What type of cell is primarily involved in killing parasites?
What type of cell is involved in allergic responses and promotes inflammation and immune response?
Once a monocyte enters a tissue from circulation, it is referred to as ______
after exposure to bacterial proteins and inflammatory stimuli
When do macrophages become activated?
receptors for: Fc region of antibodies, compliment proteins, integrins, cytokines and those that recognize LPS
What type of receptors are found on macrophages?
products of immune response and dead neutrophils
How is phagocytosis sustained by macrophages?
release proteinases to break down collagen and produce growth factors to promote new blood vessels
What role do macrophages play in wound healing?
How big must antigens be in order to be removed by phagocytic cells?
stimulate acquired immune response --> antibody production --> immune complexes --> become big enough to be removed
What happens to smaller antigens?
trap, process and present antigen to cells of immune system (antigen presenting cells)
Other than phagocytosis, what is another function of macrophages?
antibody or compliment protein
Macrophage/neutrophil can bind to a microbe that is coated with _____ or _______
What allows phagocytes to recognize groups of pathogens?
PAMP do not _____
What is the most important group of PRR?
mast cells, dendritic cells, eosinophils, macrophages and neutrophils
TLR is expressed on what cell types?
a type of PRR on phagocytic cells that recognize PAMP on microbes
What is TLR?
microbial recognition followed by engulfing and killing of microbe by phagocyte
What does interaction between TLR and PAMP allow for?
innate immune system
NK cells are part of what immune system?
by releasing perforin from granules
How do NK cells kill target cells?
receptors for complement proteins and Fc part of antibody
What type of receptors are found on NK cells?
What type of cells are important in viral immunity and defense against tumors?
NK cells receive inhibitory signals from cells that express what type of molecules?
NK cells will kill it
What happens if a target cells does not express MHC-1?
NK cells mainly kill by what mechanism?
NK cells are regulated by ______
any molecular structure the immune system recognizes as foreign and responds to
What is an antigen?
What initiates and drives the acquired immune response?
antibodies, TCR on T-lymphocyte, BCR on B-lymphocyte and MHC molecules
What can antigens interact with?
ability of an antigen to bind with immune components
What is antigenicity?
ability of an antigen to induce an immune response
What is immunogenicity?
What is the molecular size to be considered a good immunogen?
proteins and glycoproteins, bacterial LPS; prokaryotic nucleic acis can stimulate a potent immune response
What are some examples of good immunogens?
lipids and mammalian nucleic acids
What are some examples of poor immunogens?
polymer capsular coatings
What do some bacteria have that protect them from immune response?
Totally inert molecules are not ______
fix with heat or formaldehyde
How can you slow degradation and improve immunogenicity of proteins that are easily degraded?
_____ proteins make the best antigens
What plays an important role in foreignness of tissue grafts?
small portion of immunogenic molecule which actually binds with Ab/TCR/BCR
What are epitopes?
Protein epitopes are referred to as _______ if their recognition is dependent on the correct folding of the larger protein molecule
protein is changed by denaturing
Conformational epitopes will not be recognized if _______
identical or similar epitopes may be found on unrelated molecules. Ab directed toward one Ag may react with an unrelated Ag that has a similar epitope
What is cross reactivity?
Definition: Ab against foreign Ag without any known previous infection, vaccination, etc.
small molecules that are antigenic but not immunogenic in vivo
***can only elicit immune response in vivo if bound to carrier protein
What are haptens?
replication of microbe
Extracellular vs. intracellular microbes refers to where ______ happens
Most bacteria and most parasite are intracellular or extracellular?
Viruses and some bacteria are intracellular or extracellular?
Endogenous vs. Exogenous Ag refers to where Ag are _____
exogenous b/c was made outside the cell
If a pathogen was made outside a cell but was then engulfed by phagocytic cell and killed inside the phagocytic cell, the microbe would be considered.....endogenous or exogenous?
Mycobacterium, rhodococcus equi, listeria and brucella abortus are all pathogenic bacteria that produce ______ Ag
What type of Ag are obligate intracellular organisms?
go into cytosol NOT into a phagosome
Viruses enter the cell via surface molecules and go into the ______ NOT into ______
inside --> make endogenous viral Ag
Do viruses replicate inside or outside the cell?
when the virus is extracellular
When can an Ab target and kill a virus?
MHC is what type of Ag?
MHC-I can be expressed on all ______ cells
MHC-II only expressed on _____
CD4- helper T
CD8- cytotoxic (CTL)
CD4 = what type of T lymphcoyte? CD8?
MHC-II on APC
Exogenous Ag will be presented to T-lymphocytes by ____
MHC-I on any nucleated cell
Endogenous Ag will be presented to T-lymphocytes by___
free in solution
BCR recognize Ag found where?
Ag presented by APC, infected nucleated cell
TCR recognize Ag where?
Dendritic (primary), macrophages, B-lymphocytes
What are the 3 APCs? Which is primary?
immature: Ag capture
mature: processing and presenting Ag
What is the main function of immature dendritic cells? mature?
brain, parts of the eye and testes
Dendritic cells are found in all organs except _______
Which is the only APC that can present to naive T cells?
What is the main function of B cells?
bind Ag with BCR --> ingest and process the Ag --> present to T helper via MHC-II.
***When Ag binds to BCR it sends signal to B cell to differentiate into plasma cell --> make Ab identical to BCR that gave rise to plasma cell
What happens when a B cell is functioning as an APC and encounters a Ag?
Ag fragments can only trigger an immune response if they are bound to a self-MHC molecule
What is MHC restriction?
What controls antigen presentation?
The region on the MHC that actually binds Ag is highly _____
How many peptides can an MHC molecule present at a time?
MHC: broad specificity
TCR: unique specificity
MHC has _____ specificity while TCR has _____ specificity
RBC, gametes, neurons, placental trophoblast cells b/c no nucleus!
MHC-I is NOT found on what type of cells?
cytotoxic T cells (CD8)
MHC-I present endogenous Ag to ____
T-helper cells (CD4)
MHC-II present exogenous Ag to _____
foreign MHC molecules
Tissue graft rejection is due to an immune response to what?
certain MHC alleles
Almost all autoimmune diseases are linked to......
b/c if a new pathogen comes to the population, at least some people (animals) would be able to present and mount an immune response to overcome the infection
Why is being heterogenous at the MHC locus beneficial for a population?
True of False: APC can express MHC-I and MHC-II therefore can present exogenous and endogenous Ag at the same time
exogenous Ag may enter endogenous pathway and be presented via MHC-I
What is cross-presentation (cross-priming)?
shuttle Ag from exogenous pathway to the endogenous pathway and stimulate CTL response via MHC-I
What do heat-shock proteins do?
thymus, bursa, peyer's patches, bone marrow
What are the primary lymphoid organs?
What is the only primary lymphoid organ that is also a secondary lymphoid organ?
tonsils, spleen, lymph nodes, peyer's patches
What are the secondary lymphoid organs?
Lymphocytes do not encounter foreign Ag in _____ lymphoid organs
lymphocytes acquire repertoire of Ag-binding receptors, diversity of TCR and BCR, selection of lymphocytes
What happens in the primary lymphoid organs?
do not reject graft because cannot mount CMI response......very few circulating T cells!
What happens if you give an organ graft to an animal who has had a thymectomy?
in the thymus
All T cells mature where?
T cell precursors come from where?
thymocytes with TCR that bind self-Ag strongly receive signal to die by apoptosis
What is negative selection for T cells?
stay in thymus for 4-5 more days to mature and express CD3 and either CD4 or CD8.Then leave thymus to go to secondary lymphoid organ
What happens to T cells that survive negative/positive selection in thymus?
it doesn't....still have circulating lymphocytes (T cells)
How does a bursectomy in birds affect CMI?
Effector B cells = plasma cells that can make AB
Effector T cells = T helper and CTLs
What are the effector cells that are created in secondary lymphoid organs?
T cells- CMI
B cells- humoral immunity
T cells are associated with ____ immunity. and B cells are associated with ______ immunity
all progeny from a mature B cell or T cell express identical Ag receptors. Also, all Ab made from a single B cells will have the same Ag recognition
TCR and BCR are clonal. What does this mean?
leads to severe immunodeficiency syndroms b/c functional Ag receptors are not generated ---> lack immune response
What happens if somatic gene rearranement is defective?
CD25....receptor for IL-2
What is an example of a receptor for cytokines?
What type of lymphocyte comprises the majority of lymphocytes?
Which type of lymphocyte is long-lived?
Th cells will proliferate and differentiate
What happens to the Th cell when the TCR binds its specific Ag?
IL-2 and interferon gamma
What do Th1 cells secrete?
IL-4 and IL-5
****think humoral immunity
What doe Th2 cells secrete?
True or False: BCR can bind Ag that are not present by MHC molecules
sends signal through cytoplasmic part of BCR --> activate B cells to be effector cell (plasma cell) --> make Ab
What happens when a BCR binds Ag?
In order for a B cell to make Ab, they need help from ______ to become functional plasma cell
NK cells are part of the ______ immune system
Fc part of Ab and compliment proteins
NK cells have receptors for _____ and _______
regulated by cytokines
activated by IFN alpha
NK cells are regulated by _____ and are activated by _____
If a target cell does not express _____, the NK cell will recognize and kill it
1.Interact with dendritic cell via TCR and CD4 or CD8
2. co-stimulatory molecules trigger T cell entry into G1 and triggers transcription of IL-2
What are the 2 signals a naive T cells needs to become activated?
takes several days to generate effector T cells after primary response
What causes the delay in the DTH response?
inhibit Th2 differentiation, activate macrophages, activate CTL to kill other cells, help B cell make Ab
What are the functions of Th1 lymphocytes?
inhibit Th1 differentiation, promote B cells to make neutralizing Ab
What are the functions of Th2 lymphocytes?
DTH reaction is down-regulated by the production of _____
delayed local inflammatory reaction
What is an induration?
T cells, dead cells, macrophages, neutrophils, edema fluid, fibrin and fibroblasts
What is the tissue rxn resulting from DTH?
Allergic contact dermatitis and tuberculin test are examples of what type of response?
previously vaccinated for TB, exposed to a different strain, previous exposure to cross-reacting Ag
What are some possible reasons for a false-positive TB skin test?
positive: blood from animal that has been previously exposed
negative: no Ag or irrelevant Ag
What are the positive and negative controls for the IGRA test for TB?
requires single visit, results in 24hrs, does not boost response for subsequent tests, not injecting anything, prior vax does not cause false-positive
What are the advantages of IGRA over DTH skin test for TB?
Neither IGRA nor DTH test can conclude _____
Would you rather have CMI or humoral response if you were exposed to mycobacterium tuberculosis?
THIS SET IS OFTEN IN FOLDERS WITH...
SGU Immunology- Midterm Material
SGU Immunology Final - Immunodiagnostic Tests
SGU Anatomy 2: Ruminant Set 1
SGU Immunology- Post Midterm
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