Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Monoclonal antibody wikipedia , lookup
Immune system wikipedia , lookup
Lymphopoiesis wikipedia , lookup
Molecular mimicry wikipedia , lookup
Adaptive immune system wikipedia , lookup
Immunosuppressive drug wikipedia , lookup
Psychoneuroimmunology wikipedia , lookup
Polyclonal B cell response wikipedia , lookup
Cancer immunotherapy wikipedia , lookup
Immunology Notes Part 2: The Cells I. Cells of the immune system A. Monocytes: Large amount of cytoplasm in relation to the nucleus Shape is variable 1. many are round 2. some have blunt pseudopods 3. may see phagocytized erythrocytes, leukocytes, nuclei, cell fragments, pigment, bacteria, and fungi in digestive vacuoles 4. nuclei are usually round or kidney shaped, but may be deeply indented or have two or more lobes separated by narrow filaments - may have the appearance of brain-like convolutions Too large to pass readily through capillaries –extremely large ones are seldom seen in blood smears, but are found in body fluids other than blood. Remove from the circulating blood injured and dead cells and cell fragments microorganisms, and insoluble particles. Motile monophagocytes escaping between epithelial lining cellos of the upper and lower respiratory tracts and the gastrointestinal and genitourinary organs perform a scavenger function, clearing the body of insoluble and unneeded debris. Serve as first line of defense against microorganisms, entrapping and killing these foreign invaders B. Macrophages Derived from monocytes Circulating monocytes respond to inflammation and then squeeze through the endothelium where they become macrophages Main role is the removal of pathogens and necrotic debris When a macrophage ingests a pathogen, the pathogen becomes trapped in a food vacuole and fuses with a lysosome. With the help of enzymes and toxic oxygen compounds the pathogen is digested However, some bacteria such as mycobacterium tuberculosis have become resistant to this method of digestion C. Polymorphonuclear (PMNs) leukocytes: active in inflammatory process 1. Basophil have round, indented, band or lobulated nuclei granules are dark numbers increase during infection leave the blood and accumulate at the site of the infection or other inflammation They then discharge the contents of the granules (histamine, serotonin, prostaglandins and leukotrienes) which increase the blood flow to the area and in other ways add to the inflammatory process. Play a part in hayfever and anaphylactic response to insect stings 2. Eosinophil Characterized by relatively large, spherical granules which have a particular affinity for the acid eosin stain. Usually have a band or two-lobed nucleus. Granules are spherical are uniform in size and usually evenly distributed, fill the cell and rarely overlay the nucleus In a good stain, the granules take a bright reddish-orange stain with brownish tints. Gather wherever there is a parasite infection or allergic reaction such as allergic asthma and then release their toxins. The toxins are very efficient at harming parasites, but will also harm us if released in the wrong place ( lining of lungs can become damaged in asthma ) 3. Neutrophil Granules do not readily stain with either dye. Neutrophils (polymorphs), which can remove and kill bacteria and particles of foreign material. The name 'neutrophil' ('neutro' = neutral, 'phil' = loving) comes from the fact that they contain granules which are neither acidic nor alkaline . The name 'polymorph' ('poly' = many, 'morph' = shape) comes from the fact that like almost all cells in the body they have a nucleus, but unlike other cells their nucleus can have a variety of (many) shapes, consisting of usually one to five connected lumps or 'lobes'. D. Lymphocytes: A. T-Cells 1. Cytotoxic T cells: (CD8+) destroy infected cells. These cells function as “killer” or cytotoxic cells because they are able to destroy target cells which express specific antigens that they recognize. 2. Helper T Cells (CD4+): are “middlemen” in the immune response. When they get activated they proliferate and secrete cytokines that regulate effctor lymphocyte function. They are known as the targets of HIV infection and the decrease of CD4+ T cells results in AIDS. Some helper T cells secrete cytokines that turn off the immune response once an antigen has been eliminated from the body 3. Regulatory T cells (suppressor T cells) suppress activation of the immune system and maintain immune system homeostasis. Failure of regulatory T cells to function properly may result in autoimmune diseases in which the immunocytes attack healthy cells in the body. CD = Clusters of Differentiation Every effective immune response involves T cell activation; however, T cells are especially important in cell-mediated immunity, which is the defense against tumor cells and pathogenic organisms inside body cells. They are also involved in rejection reactions. B. B Cells *Each B cell is programmed to make one specific antibody. For example, one B cell will make an antibody that blocks a virus that causes the common cold, while another produces antibody that zeros in on a bacterium that causes pneumonia. When a B cell encounters its triggering antigen(along with collaborating T cells and accessory cells), it gives rise to many large plasma cells. Every plasma cell is essentially a factory for producing antibody. Each of the plasma cells descended from a given B cell (which are all members of the same family, or clone) manufactures millions of identical antibody molecules and pours them into the bloodstream. A given antibody matches an antigen much as a key matches a lock. The fit varies: sometimes it is very precise, while at other times it is little better than that of a skeleton key. To some degree, however, the antibody interlocks with the antigen and thereby marks it for destruction.