Immunologie (Fach) / Basiswissen Immunologie (Lektion)

Grundlagen der Immunologie

Diese Lektion wurde von Yannee erstellt.

Lektion lernen

zurück  |  weiter 1 / 3

• Name the differences between the innate and the adaptive immune System. Innate immune system: fast old general patterns Adaptive immune system: slow new antigen specific
• From which cell do all mobile immune cells derive and what is the Name of the place? All mobile cells of the immune system derive from pluripotent hematopoietic stem cells in the bone marrow.
• What is the Name of cells which are not differentiated yet? Progenitor cells
• Which two lineages form immune cells? Lymphoid and myeloid
• How does macrophages recognize and endocytose pathogens? They use old recognition mechanism (TLR)
• What do Dendritic cells? They endocytose antigen and present it to T-cells.
• Name the different T-cells and explain short their exersices. Where do they practise? They learn their exercises in the thymus. There are T-killer cells (CD8). CTL kill viral infected cells. There are also T helper cells (CD4). Th1 help macrophages to kill intracellular bacteria. Th2 help B-cells produce antibodies.
• What do B-cells (in short) They develope themselves in the bone marrow. They produce antibodies after activation by Th2 cells.
• How did T-cells recognize pathogens? T-cells only recognize processed presented antigen. Either on professional antigen presenting (cell APOs) to activate T-cells or on virally infected cells to kill them
• Name three Professional Antigen presenting cells (Apc) Dentritic cells Macrophages B-Lymphocytes
• What does the lymphatic System? And where are the Organs of the immune System? The organs are distributed all over the body. The lymphatic system collect liquid from the tissue. They lead it back to the blood circulation via thoralic duct and subclavian veins. The lymph is filtered and checked for pathogens and antigens in the lymph nodes. The lymph capillaries are in the tissue spaces.
• Where in the lymph node are the B-cells? The B-cells are mainly in the primary lymphoid follicle.
• Where in the lymph node are the T-cells? The T-cells are mainly in the Paracortial area.
• Explain in short the Course of an Inflammation. Bacteria trigger macrophages to release cytokines and chemkines Vasoldilation and increased vascular permeability cause redness, heat and swelling inflammatory cells migrate into the tissue, releasing inflammatory mediators that cause pain.
• Draw the structure of an antibody and a T-cell receptor s.Bild
• What does b-cells produce? They produce antibodies which consist of a Fab fragment (antigen binding fragment) and an FC Fragment (crystallizable fragment)
• What can antibodies do with bacterial Toxins? Antibodies can neutralize bacterial toxins. They bind tógether on them. After them a macrophage can ingest the toxins.
• What can antibodies do with Bacteria in extracellular space? They opsonizate the bacterium, that means they hold him and show the macrophages where to find them. The macrophage can ingest the bacterium now much easier.
• What can antibodies do with bacteria in Plasma? They can do a complement activation. First they opsonizate plus complement. Than the lysis and ingestion by a macrophage happend.
• What do Th1 cells do to help the macrophages? Th1 cells superactivate macrophages to kill intracellular bacteria inside the macrophage. Lysosomes helps.
• What did a Virus infected cell do? Who can help this cell? They produce the DNA from the virus. A cytotoxic T-cell kills the infected cell.
• Name two functions of the lymphatic system recovery of fluids from the tissue, surveillance of periphery by the lymph nodes, sweeping bacteria into the lymphatic system insted of blood system in an infection.
• Why do you observe, heat, swelling and redness during an Inflammation? Dilatation of blood vessels, which leads to more volume and decreased velocity of blood flow in blood vessels, increased permeability of vessel walls, which leads to an increased flow of fluids from the blood to the tissue.
• Name the five classes of pathogens Bacteria virusses funghi protozoans worms
• What do pathogens? Why are they dangerous? Pathogens cause tissue destruction, some release toxins.
• What is a systemic infection? The infection is widepread throughout the body and must be assumed to be in all organs
• How is Sepsis caused? Sepsis is caused by an innate immune response triggered by a systemic infection.
• What is an anaphylactic shock? Overreaction of the adaptive immune system
• Name the first barriers against pathogens skin stomach with low pH In the lungs, pathogens are clustered with the help of mucus IgA and moved by cilia to the throat, where they are swallowed. Eyes liquid contains lysozyme which kills bacteria. On the skin and in the intestine, beneficialbacteria prevent infection by competition for space and nutrients
• Name the second barriers against pathogens Immune cells, especially macrophages, which recognize pathogens directly, or when they are coated in antibodies , one example of the cooperation of innate and adaptive immune system. Macrophages bind to Fc portion of the antibodies with their Fc receptors. Binding of antibodies to pathogen make it recognizable and edible, a process called opsonization (not only by antibodies but all immunogenic proteins that bind to pathogen surfaces).
• What means Opsonization? Binding of antibodies to pathogen make it recognizable and edible, a process called opsonization (not only by antibodies but all immunogenic proteins that bind to pathogen surfaces).
• Was bedeutet MBL. Was macht es? Das Mannose-bindende Lektin (MBL) ist ein Protein des angeborenen Immunsystems in Säugetieren. Beim Menschen wird das Protein in der Leber als Reaktion auf eine Infektion produziert und ins Blut ausgeschüttet. MBL ist Mitglied der Akute-Phase-Proteine und ein Collectin. Collectine gehören zur Obergruppe der C-Typ Lektin-Rezeptoren, deren Aufgabe die Erkennung fremder Strukturen als erste Stufe der Immunabwehr ist. MBL erkennt hierbei Kohlenhydrat-Muster, die sich auf der Oberfläche einer großen Anzahl von pathogenen Mikroorganismen, unter anderem Bakterien, Viren, Protozoen und Pilze befinden. Wenn das MBL an einen Mikroorganismus bindet, folgt die Aktivierung des Komplementsystems über den Lektin-Weg.
• Where did MBL carbohydrat-recognition Domains bind to the pathogen? And why? They bind to pathogen surface mannose and fucose because of their precise spacing.
• Why did one MBL receptor only binds with too low affinity? if all bind at the same (like on a pathogen), avidity effect results in MBL sticking to the pathogen.
• What are PAMPs? (pathogen associated molecular patterns) and they are conserved patterns on or inside pathogens.
• What are PRRs? Receptors that recognize PAMPs are called PRRs (pattern recognition receptors).
• How do immune cells know where bacterias are? Bacteria often secrete formyl-methionine-leucyl-phenylalanine (FMLP), as bacterial translation starts with formyl methionine. The immune cell follows the FMLP gradient and chases the bacterium.
• What are Toll receptors? Toll was first discovered in Drosophila by C. Nüsslein-Volhard as a protein important for the fly‘s development. The Toll signaling pathway is very conserved, itis one of the oldest molecules involved in immunology. In 1996, it was found that toll plays a role in fly antifungalimmunity, as toll deficient flies quickly succumb to fungal infection.
• What are TLRs? Toll like receptors, a very similiar gen like Toll receptor which humans has. It has the general functions like Toll receptors. different Toll-like receptors recognize different PAMPs. Different TLRs are either present at the cell surface or in endosomes.
• What do the complement System? Proteins of the complement system are present in their inactive form (as preproteins)in the blood plasma. Upon activation they form a protease cascade, which serves for signal amplification.
• What are the three functions of the complement System? 1. Recruitment of immune cells 2. Opsonizationof pathogens 3. Killing of pathogens
• How can the complement System can be activated? It can be activated by three different pathways: the classical pathway, which is activated by antigen:antibodycomplexes, the lectin pathway, which can be e.g. activated by MBL and the alternative pathway, where a complement protein can spontaneously attach to pathogen surfaces.
• Explain the lectin pathway MBLand Ficolinscan activate the Lectinpathway. Activated MASP-2 cleaves C4 to C4a and C4b. C4b binds to C2, which is then cleaved by MASP-2 (Mannan-binding lectinserine protease 2) to C2a and C2b and then the C4b2a complex forms.
• Which three different functions have the different complemet molecules? The differentpathways activate different complement molecules, all activating C3 convertase. In turn, the different parts of C3 and additionally recruited molecules mediate the 3 different functions: C3a and C5a act as peptide mediators of inflammation and recruit phagocytes, C3b can opsonize pathogens and mark them for phagocytosis by cells which possess complement receptors and C5b, C6,C7,C8 and C9 form the membrane-attack complex, which leads to cell lysis.
• What are immune complexes? Small antigens like toxins or cell debris are bound by antibodies and the complement system to form immune complexes. These complexes are bound by CR1 on erythrocytes via C3b and transported to the spleen and liver, where the immune complexes are removed by phagocytic cells.
• Explain leukocyte homing During an infection in the tissue, macrophages, which recognize and endocytose the pathogen, become activated and secrete cytokines. These cytokines will stimulate the endothelial cells which form the walls of nearby capillaries to become more permeable for fluids and to express certain surface receptors, mostly selectins. Selectins will bind to glycoproteins on leukocytes in the blood and lead to ‚rolling adhesion‘: leukocytes slow down and roll along the capillary wall. Eventually, the leukocytes will squeeze through to the tissue between two epithelial cells, a process called extravasation. In the tissue, the leukocytes follow the concentration gradient of chemokines (secreted by macrophages), which will lead them to the infection. The whole process is called leukocyte homing.
• What is an Antigen? A structure that is bound/recognize by the adaptive immune system
• What is opsonization? Opsonization is the covering of pathogens with immune proteins (antibodies) to make them easier eadible by phagocytic cells.
• What are PRRs? Name two examples. PRRs are receptors that recognize conserved patterns on pathogens, TLR or MBL
• How can the complemet System can be activated? Name three examples By the classical pathway the lectin pathway the alternative pathway

zurück  |  weiter 1 / 3