Term
| What are the roles of neutrophils? |
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Definition
| Most numerous WBC, migrate rapidly to sites of infection, kill pathogens via phagocytosis |
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Term
| Difference between monocytes and macrophages? |
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Definition
| Monocytes are blood derivates and macrophages are activated in tissues |
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Term
| What are examples of fixed macrophages? |
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Definition
| Kuppfer cell in sinusoids of liver, function to phagocytose particulate matter |
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Term
| What is the most important cytokine for phagocyte recruitment? |
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Definition
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Term
| What does IL-8 do specifically? |
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Definition
| Modifies neutrophil integrins, acting as chemokines to bind endothelium |
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Term
| What are three types of receptors phagocytes have? |
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Definition
TLRs - danger signals and cytokine producion
C lectin receptors - Recognizes sugars on mammalian cells, activates macrophages
Complement receptors - bind pathogens, stimulate inflammatory response |
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Term
| how do phagocytes recognize IgG? |
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Definition
| Through Fc receptors, as IgG help to activate phagocytosis of internalized antigens |
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Term
| What is the respiratory burst? |
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Definition
| Enzyme pathways that after phagocytosis, help to produce toxic molecules and kill pathogens. Hydreogn peroxidases, HOCL and NO |
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Term
| What molecules are important in lysosomal degradation of pathogens? |
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Definition
| Defensins and lactoferrins are released into phagosome, deprives it from iron or punches hole into bacteria |
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Term
| What is the Acute phase response? Cells and cytokines involved? |
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Definition
Initial reactions to infection or virus, macrophages secrete Il-1, IL-6, TNF-a to increase production of complement
Increase body T via hypothalamus (TNF-A) |
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Term
| What is the link between macrophages and adaptive immune system? |
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Definition
| IgG is the best opsonizer of bacteria, allows macrophages to kill. Macrophages and IgG are sustained by Th1 responses, while IF-G supports macrophages during chronic inflammation, unlike IF-A/B which have viral functions |
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Term
| Why are worms such an issue to the human body?How are they dealt with? |
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Definition
| Resistant to natural barriers like low ph and proteolytic digestion. Mast cells and eosinophils evolved to respond to worms |
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Term
| What cytokines influence Th2 production? |
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Definition
| Th2 response under influence of Il-4, Il-3,Il-6. |
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Term
| Describe the allergic response |
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Definition
| Antigen released by worms stimulate Th2 and B cells- class switching produces IgE, binds to mast cells. Next encountering of antigen leads to mast cell degranulation. Bound to mast cell by Fc prtion. |
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Term
| What do mast cell granules contain? |
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Definition
| Tryptase, chymotrypsin - increase mucus, activate complement and kinin pathways |
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Term
| What cytokines are released in mast cell granules? |
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Definition
| TNF (diapedesis), IL-4 (other th2 cells), Il-3,5 (eosinophil production) |
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Term
| What are the differences between eosinophils and mast cells (2) |
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Definition
| Specifically recruited to tissue for inflammation, granules contain toxic substances (not just enzymes). Triggered by IL-3,5. HOCL released, and major basic protein (damages parasite outer surface) |
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Term
| What is a type 1 hypersensitivity reaction? |
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Definition
| Allergic hypersensitivtiy caused by innocuous antigens like pollens |
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Term
| What are two main roles of NK cells? |
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Definition
Excellent killers of cells infected with viruses
Stimulate adaptive immune response (similar to macrophages) |
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Term
| How do NK cells function? |
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Definition
| Recognize when MHC expression is downregulated, release toxic chemical like granzyme, perforin and fas ligand to kill cell. |
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Term
| Why aren't NK cells considered adaptive? |
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Definition
| Don't have rearranged T cell molecules, but phenotypically identical |
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Term
| How do NK cells interact with IgG? |
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Definition
| Fc receptors recognize IgG bound viral antigen, triggers killing (antibody depedant cellular cytotoxicity) |
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Term
| what is the role of Killer immunoglobulin like receptors |
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Definition
| Recognize MHC alpha chains, and when a NK cell recognize virally infected cell, if MHC expression is low, it will kill it |
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Term
| What is a non main function of NK cells? |
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Definition
| Major immune cell of pregnant uterus |
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Term
| How does perforin, granzyme and fas ligand work? |
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Definition
Perforin - cats like complement and creates a pore in target cells
Granzyme - activate caspase and degrade host proteins
Fas - potent inducer of apoptosis, like TNF receptors (not involved in inflammation) |
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Term
| When NK encounter target cells, how do they communicate with adaptive immune system? |
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Definition
Secrete IFN-g (TH1 cytokine) and inhibits TH2 cells
TH1 are better at cellular cytotoxicity and intracelullar infection |
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Term
| What is the role of phagocytes and apoptosis? Necrosis? |
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Definition
| NEeded to recognize apoptotis cells and clear the cell remains without stimulating inflammation. However, necrosis often results in inflammatory response |
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Term
| What defines inflammation? |
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Definition
Redness, swelling and pain.
Edema fluid, pus formation |
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Term
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Definition
| Chronic inflammation mediated by mast cells and eosinophils |
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Term
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Definition
| Collections of specialized macrophages surrounded by T cells - delayed hypersensitivity |
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Term
| What three main cytokines does macrophages produce? |
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Definition
IL-1, TNF -A, GM-CSF. TNF and IL-1 increase adherence of leukocytes to local endothelium.
GM-CSF activate acute phase response |
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Term
| do macrophages preferentially stimulate Th1 responses? |
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Definition
| Yes, through Il-12 and Il-1 sgnalling |
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Term
| How do macrophages and th1 cells create cytokine circle/network? |
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Definition
| Macrophages secrete IL-1 and 12 to activate TH1 cells. Th1 cells then secrete IFN-g which activates macrophages and inhibit Th2 cells |
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Term
| What are two types of tests for TB? |
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Definition
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Term
| How does the skin test for Tb work? |
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Definition
Intradermal injection of tuberculin (mantous test)
TLRs on dermal macrophages should recognize mycobateria and release TNF. If previous response existed, T cell will be responsive. IF no prior sensitization, no respones. Those vaccinated will produce moderate response |
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Term
| What does the blood test for TB measure? |
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Definition
| IFN-G production by TH1 cells responding to TB peptides |
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Term
| Are adaptive immune system cytokines secreted at high or low levels? why? |
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Definition
| Low levels, like Il-2, as it has very high specificity to TH1 cells and CD8 cells. |
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Term
| What are two features of cytokines in the immune response? |
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Definition
Redundant (several do the same thing)
Pleiotropism - affect many tpes of cells |
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Term
| What cytokines help develop specialized T cell responses int the gut? |
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Definition
| Gut T cell secrete TGF-B that induces class switches form IGM to IGA |
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Term
| Name two inhibitory cytokines that could dampen immune response? |
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Definition
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