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30 Cards in this Set
- Front
- Back
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Inflammation is a localised response triggered by stimulus that kills cells/injures tissue and is characterised by 4 features: |
Swelling (tumor), Redness (rubor), Heat (calor) and Pain (dolor) |
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What are the 4 immune-privileged organs? Why are these sites classified as such? |
Brain, eye, testis and thyroid gland Immune system may not recognise specific structures in these regions and proceed to damage them, resulting in loss of function |
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Humoral immunity is immunity mediated by soluble factors such as cytokines. What factors grant this sort of immunity? Cellular immunity is immunity mediated by immune cells. What are some examples? |
Humoral immunity is given by soluble factors like complements, cytokines/chemokines and antibodies Cellular immunity is given by immune cells like neutrophils, macrophages, NK cells, lymphocytes, etc |
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Granulocytes, macrophages, mast cells and NK-cells have an innate immunity. Describe some characteristics of such types of cells. |
BM-derived cells. Are released into the body to various parts to carry out their specific functions |
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M-cells, dendritic cells and follicular dendritic cells are cells found in the intermediate zone between innate and adaptive immunity. Describe some of their characteristics. |
M-cells: Epithelial cells that are mostly found in the gut and respiratory tracts that take antigens and present them to resident immune cells DC: Monocytic cells (subpop of macrophages) that migrate to and present antigens to T cells FDC: Stromal cell-derived cells located in areas with B cells and present antigens to these B cells |
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T and B-lymphocytes have adaptive immunity. What are some of their sub groupings? Where do they develop and mature |
T-cells: CD4+, CD8+ B-cells: Memory cells, Plasma cells [produce antibodies] Both develop in the BM. B cells mature there but T cells mature in the thymus. |
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Contrast neutrophil granulocytes with macrophages |
Both are phagocytic cells that internalise pathogens and lysosomally degrade them. Neutrophils: Do not reside in tissues; Survive up to 24 hours; Very mobile; Die after phagocytosis Macrophages: Survive for a few months; Act as antigen presenting cells to T cells |
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Detail the class switch of macrophages |
M1 => M2 phenotype M1: Primary role is to endocytose and eliminate pathogens M2: Role is now to repair damaged area |
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Eosinophilic & Basophilic granulocytes, Mast cells and NK cells deliver substances from storage granules, kill parasites/tumour cells and induce/support the inflammatory response. Detail more about each cell type |
Eosinophil: Constitute 1-6% of all WBCs. Contribute to initiation of immune response, combating parasites, viral infections, allergies and asthma Basophils: Constitute 0.01-0.3% of all WBCs. Release heparin, histamine and promotes blood flow to tissues Mast Cells: Found in various tissues, not in circulation. Granules contain heparin, leukotrines and histamine. Has T cell dependent (MMC) and independent cell types (CTMC) NK cell: Constitute 3.5% of all WBCs. Can destroy pathogens without specific markers, induce tumour cell apoptosis, release interferon gamma which activates macrophages |
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M-cells are like a bridging cell. Elaborate Further, note the functions of dendritic cells and FDCs |
They transport antigens from the lumen to the lamina propria - a movement the antigens cannot normally perform on their own DC: Present the antigens to T-lymphocytes FDC: Present antigens to T-and B-lymphocytes |
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Naive B cells are primed according to the antigen presented. With help of ___ and ___, they mature into plasma cells and produce ___ [IgM, IgG, IgA, etc]. Memory cells are also made as they react faster to same ___, as FDCs are no longer required for activation |
T cells; FDCs; antibodies; antigen |
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What are memory cells? |
Cells that are inactive but primed to respond to pathogens they have previously been exposed to |
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Note the functions of antibodies ___ work by specific AB produced over long time |
Bind to antigenic molecules; Help phagocytosis; Toxin and virus neutralisation Vaccines |
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Antibodies IgA, IgE, IgD are added to ___ Antibodies IgM, IgG are added to ___ |
Gland secretions (ie tears; gut, nasal and bronchial surfaces) Blood and extracellular liquid |
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Antibody constant region binds on ___ Antibody variable regions bind to antigen ___ |
cell surface epitopes |
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Why is IgM produced faster than IgG in a primary AB response? |
It has more antigen binding sites. However, it is less effective than IgG in a secondary AB response |
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What is antibody class switching? Provide an example. What factors can influence this? |
The changing of B cells’ production of immunoglobulin from one type to another [eg IgM (Primary response) to IgG (Secondary response)] Epigenetic modifications (noncoding RNAs, histone mods, DNA methylation, etc) all contribute to antibody maturation and class-switch recombination |
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Detail T-cell activation by Class II MHC proteins |
Class II MHC protein displays antigen and activates CD4+ T cells which divide, differentiate and perform multiple specific roles such as:
- Helper T cells stimulate immune response by T and B cells
- Memory helper T cells await reappearance of the antigen |
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There are two classes of CD8+ cells that are activated by exposure to antigens on MHC proteins. What are their responses? |
One type responds quickly - cytotoxic T cells and memory T cells One type responds slowly - suppressor T cells (aim to quieten activated cytotoxic T cell response) |
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Note functions of Helper T cells |
Produce cytokines Regulate and support B-cell differentiation (recognise same AG) Support cytotoxic T-cell function (activation of CD8+ cells) Recognise different parts of same AG (epitopes) |
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How do class I MHCs come to present their antigens? How do class II MHCs come to present their antigens? |
Infected cell: Abnormal peptides in the cell are taken in by the ER, which links them with MHC1 proteins. MHC1 is transported to the cell membrane so it can present the antigen Phagocytic antigen-presenting cell: Pathogen phagocytosed by APC and fragmented by the action of lysosomes. MHC2 protein from ER is bound with antigen and transported to cell membrane surface for antigen display |
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Helper T cells [CD4+] have many subdivisions - two of which are T helper 1 cells (Th1) and T helper 2 (Th2) cells. What do each do? |
Th1: Produce pro-inflammatory cytokines which stimulate the immune system [eg IL 2, 6, 12] Th2: Produce anti-inflammatory cytokines which suppress the immune system [eg IL-4, 5, 10] |
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Detail T-cell activation by Class I MHC proteins |
Class I MHC protein displays antigen and activates CD8+ T cells which divide, differentiate and perform multiple specific roles such as: - Cytotoxic T cells attack and destroy infected cells displaying antigen - Memory T cells await reappearance of the antigen - Suppressor T cells mediate immune response by T and B cells |
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CD8+ cells sometimes require activation by Helper T cells. NK cells however do not. Note how they interact with abnormal cells |
NKs identify and attach to abnormal cells. Along with other mechanisms, they release perforin, which lyses the abnormal cell membrane |
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NK cells are large granular lymphocytes, constituting ___ of all circulating lymphocytes ___ in NK cell produces perforin vesicles NK cells and B cells act via humoral/cell-mediated immune action |
5-10% Golgi apparatus humoral [because no processing of MHC complex] |
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Toll like receptors allow the immune response to be controlled and selective cell activation. They produce... |
chemokines and cytokines |
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Cytokines... |
Stimulate T cell division, producing memory T cells and accelerating cytotoxic T cell maturation. They also attract and stimulate macrophages and NK cells, as well as promoting B cell activation [Pro-inflammatory actions] |
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Interferons are released by activated lymphocytes and macrophages. What produces alpha, beta and gamma interferons and what do they do? |
Alpha: Secreted by leukocytes and stimulate NK cells Beta: Secreted by fibroblasts and slow inflammation Gamma: Secreted by T and NK cells and stimulate macrophages |
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What are chemokines and some of their characteristics and roles |
Chemokines are signalling proteins secreted by cells. - They are 10kd in size - They direct cell migration (via chemotaxis) - Can activate T and B cells - Have a role in tumour formation - Perform homeostatic functions |
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Complements are part of the innate immune system. They're the primary humoral defense against bacteria & viruses. What is their function? More than ___ serum and cell-surface proteins involved in inflammation and immunity. Most complement proteins in serum are produced by ___ |
Enhance ability of antibodies and phagocytic cells to clear pathogens 30 liver hepatocytes |
