Immune System - Science Olympiad
What are the overview, causes, symptoms, and if any, treatment of Addison's disease?
- Overview: Addison's disease, also called adrenal insufficiency, is an uncommon disorder that occurs when the body doesn't produce enough of certain hormones. In Addison's disease, the adrenal glands, located just above the kidneys, produce too little cortisol and, often, too little aldosterone. Addison's disease can develop if your immune system attacks your adrenal glands and severely damages your adrenal cortex. When 90% of the adrenal cortex is destroyed, your adrenal glands will not be able to produce enough of the steroid hormones cortisol and aldosterone. - Causes: Addison's disease can develop if your immune system attacks your adrenal glands and severely damages your adrenal cortex. When 90% of the adrenal cortex is destroyed, your adrenal glands will not be able to produce enough of the steroid hormones cortisol and aldosterone. - Symptoms: The general symptoms of Addison's disease are: - Treatment:
What are the overview, causes, symptoms, and if any, treatment of asthma?
- Overview: Asthma causes the inside walls of the airways, or the bronchial tubes, to become swollen and inflamed. During an asthma attack, the airways swell, the muscles around them tighten, and it becomes difficult for air to move in and out of the lungs. Asthma is not considered an autoimmune disease. - Causes: Asthma attacks may be triggered by inhalation of certain substances, such as dust or smoke, which cause the muscles to tighten. Asthma is most likely acquired through environmental factors and inheritance, and thus it isn't caused by any particular pathogen. - Symptoms: Wheezing, chest tightness, shortness of breath, coughing. Moderate to extreme discomfort while breathing. - Treatment: Treatment for asthma involves using bronchodilators to expand the diameter of the bronchi. Rescue inhalers during an asthma attack have albuterol in them. Long-term use inhalers generally have formoterol, salmeterol, or tiotropium. There is no cure to asthma, and someone born with asthma will most likely have it for the rest of their lives.
What is IgD?
Immunoglobulin (Ig) D is an immunoglobulin with a delta heavy chain present on the surface of B lymphocytes or as a soluble form in plasma. IgD and IgM are coexpressed on the surfaces of most peripheral B cells. IgD is normally expressed in resting mantle cells and can be useful in identifying primary follicles.
What is IgA?
Immunoglobulin A is an antibody that plays a role in the immune function of mucous membranes. IgA produced in association with mucosal membranes is second most common. In secretions, it serves to protect the mucosal tissues from microbial invasion and maintain immune homeostasis with the microbiota.
What is IgE?
Immunoglobulin E (IgE) are antibodies produced by the immune system and if an allergy is present, the immune system overreacts to an allergen by producing antibodies called immunoglobulin E (IgE). These antibodies travel to cells that release chemicals (such as serotonin and histamine), causing an allergic reaction.
What is IgG?
Immunoglobulin G is a type of antibody. Representing approximately 75% of serum antibodies in humans, IgG is the most common type of antibody found in blood circulation. The functional activities of IgG molecules, such as bactericidal effect mediated by complement, viral neutralization, inactivation of toxins and opsonization, are important for the development of an effective immune response against a large range of microorganisms and their toxic products. In other words, it aids in preventing infections.
What is IgM?
Immunoglobulin M is one of several isotypes of antibodies that are produced by vertebrates. IgM is the largest antibody, and IgM is the first antibody isotype produced during an immune response and functions as a primary barrier against pathogens.
What is innate immunity?
Innate, or nonspecific, is a defense that is active immediately upon infection and is the same whether or not the pathogen has been encountered previously, and is present at birth and lasts a person's entire life. In other words, innate immunity is the first response of the body's immune system to a harmful foreign substance.
What are interferons?
Interferons are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten their anti-viral defenses.
What are lymph nodes?
Lymph nodes filter substances that travel through the lymphatic fluid, and they contain lymphocytes (white blood cells) that help the body fight infection and disease. There are hundreds of lymph nodes found throughout the body/tissues, with the exception of the avascular tissues (e.g. cartilage, epidemis, cornea, CNS,). They are only called "lymph nodes" when occured singularly, but when clustered in groups, it will become a "lymph gland".
What are lymphocytes and what cells are under that category?
Lymphocytes are white blood cells that concentrate in lymphatic tissues such as the lymph nodes, thymus gland, and the spleen. They are the primary agents of the immune response. Such cells are B cells, plasma cells, and memory cells.
What is MHC class II?
MHC Class II is typically displayed by antigen-presenting cells, or APCs: B-cells, macrophages, and dendritic cells. After an APC consumes an antigen, the proteins in the antigen are broken up and displayed as epitopes on the Class II MHC molecules of the APC. Helper T-cells will dock their CD4 receptors to MHC Class II molecules. If the helper T-cell is "naive" and has not been exposed to any antigens, the T-cell receptors will bind to the epitope and learn to recognize that particular antigen. This activates the helper T-cell, which can now start secreting cytokines and multiplying itself. The cytokines tell nearby B-cells and cytotoxic T-cells to look for that antigen and kill it via apoptosis or antibody production.
What are macrophages?
Macrophages are larger, long-living versions of monocytes. Monocytes circulate through the blood stream, and are known as macrophages when they mature. Macrophages move throughout blood, lymph, and body tissues, whereas others reside permanently in organs and tissues where they are likely to encounter pathogens. They are specialized in the removal of dying or dead cells (scavengers) and cellular debris as well as pathogens. Macrophages also play an important role in chronic inflammation.
What are mast cells?
Mast cells reside in connective tissues and mucous membranes, and they also secrete histamine, as well as serotonin. They help cause inflammation and respond to wound injuries.
What are memory cells?
Memory cells are long-living B cells that do not release antibodies by circulating through the body and respond to subsequent invasions. Memory B cells provide immunity, as their response is much more quick and powerful that the first occurrence.
What are natural killer cells (NK cells)?
NK cells attack abnormal or pathogen-infected body cells, such as tumors, by releasing toxic granules to kill the cells.
What is the neutrophil cell?
Neutrophils are the most abundant type of white blood cell. They are normally present in the blood stream, but quickly enter tissues to phagocytize pathogens, primarily bacteria, in acute inflammation. They respond within minutes to the site of injury.
What is non-self molecules?
Non-self molecules are those recognized as foreign molecules, and one class of it is antigens.
What is phagocytosis?
Phagocytosis is an important feature of cellular innate immunity performed by cells called 'phagocytes' that engulf, or eat, pathogens or particles. Phagocytes are white blood cells (leukocytes) which engulf pathogens by extending pseudopods to surround it. Leukocytes are formed in stem cells in bone marrow through the process of hematopoiesis (this term refers to all blood cells).
What is a plasma cell?
Plasma cells, also called plasma B cells or effector B cells, are white blood cells that originate in the lymphoid organs as B lymphocytes and secrete large quantities of proteins called antibodies in response to being presented specific substances called antigens. These antibodies are transported from the plasma cells by the blood plasma and the lymphatic system to the site of the target antigen (foreign substance), where they initiate its neutralization or destruction.
What are basophils?
Rarest WBC's, are funtionally similar to mast cells, have large, purplish black (basophilic) granules that contain histamine.
What are self molecules?
Self molecules are those components of an organism's body that can be distinguished from foreign substances by the immune system.
What are T cells?
T cells originate in the bone marrow but mature in the thymus gland (t as in thymus), and they have antigen receptors which are not antibodies but recognition sites for molecules displayed by nonself cells. Nonself cells, such as invading body cells, cancer cells and tissue transplant cells, display different markers than self cells. When T cells encounter a nonself cell, they divide and produce two kinds of cells, cytotoxic T cells (killer T cells) and helper T cells.
What is the adaptive immune system?
The adaptive immune system, also known as the acquired immune system, is a subsystem of the immune system that is composed of specialized, systemic cells and processes that eliminate pathogens or prevent their growth. It is the third line of defense of the immune system, and it targets specific antigens.
What are antibodies, or immunoglobulins (Ig), of B cells and what are the 5 classes?
The antibodies, or immunoglobulins(Ig) of B cells are antigen receptors only to a particular antigen. Antibodies inactivate antigens by binding to them, stimulating complement proteins to promote macrophage phagocytosis. There are 5 classes of antibodies, each a variation of the basic Y-shaped protein with variable regions which give them specificity to antigens. The 5 classes are as follows: IgA, IgD, IgE, IgG, and IgM.
What is the immune system?
The body's defense against disease causing organisms, malfunctioning cells, and foreign particles. In other words, it is a complex network of cells, tissues, organs, and the substances they make that help the body fight infections and other diseases.
What is cell-mediated response?
The cell-mediated response occurs as a response to nonself cells, and involves mainly T cells. 1. In a celluar infection, antigens are broken down by the cell and presented at the cell surface by class I MHC proteins. 2. T cells bind to the MHC detect antigens and undergo clonal selection, initiating the production of cytoxic T cells and helper T cells. 3. Helper T cells bind to macrophages which are displaying marker combinations which signal with marks that they have engulfed a pathogen. 4. Helper T cells produce interleukins, communication chemicals, to stimulate T cell and B cell proliferation. This initiates a posive-feedback cycle, increasing the concentratin of leukocytes in the area.
What is the complement system?
The complement system, also known as complement cascade, (it consist of 30 proteins) is a part of the immune system that enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane. They bind to the surface of microbes to ensure white blood cells can phagocytize the microbe and produce holes in the bacterial cell walls and membranes. In other words, the complement system is a group of about 30 proteins which assist defense reactions. They help by enhancing the process of phagocytosis, attracting phagocytes to foreign cells, and promoting cell lysis. They are generally synthesized by the liver.
What are the 3 strategies within the second line of defense?
The first type is an inflammatory response, which is characterized by swelling, redness, soreness, and increased warmth in the affected area. The purpose of this process is to increase oxygen and white blood cells to fight disease. The second type is phagocytes, which ingest up invading microbes. Macrophages ("giant eaters") are a type of white blood cell that extends pseudopods and engulfs huge numbers of microbes over a long period of time. The third type is interferons, which are chemicals that are released by the immune system to "block" against viral infections.
What is humoral response?
The humoral response, or antibody-mediated response occurs as a response to antigens or pathogens circulating in the blood or lymph. It is crucial (one of the primary functions) in protecting the body against extracellular pathogens. 1. An antigen is engulfed by a phagocyte. It displays the antigen on its surface using a class II MHC protein. 1. B cells recognize the antigen and produce plasma cells, which release antibodies that bind with antigens or antigen-carrying pathogens. 2. B cells produce memory cells, providing future immunity. 3. Macrophages and helper T cells stimulate B cell production through cell-mediated response.
What is the immune system subdivided into?
The immune system is made up of two parts: the innate immune system and the adaptive immune system.
What is the inflammatory response?
The inflammatory response (inflammation) occurs when tissues are injured by bacteria, toxins, or any other cause. The damaged cells release chemicals including histamine, bradykinin, and prostaglandins. These chemicals cause blood vessels to leak fluid into the tissues, causing swelling, redness, pain, dysfunction of organs involved (tumor, dolor, rubor, calor, and functio laesa, respectively), and heat. -> Histamine triggers vasodilation (enlargement of blood vessels), which increases blood supply to the area, bringing more phagocytes to gobble up germs. Histamine is also responsible for the symptoms of the common cold: sneezing, coughing, redness, and itching and runny nose and eyes; all an attempt to rid the body of invaders. -> Increased body temperature speeds up the immune system and makes it more difficult for microbes to function.
What does the innate immunity include?
The innate immunity has two lines of defenses; the first line of defense is a barrier that aids in preventing pathogens from entering the body (to block entry), with examples such as: skin that secretes oily and acidic secretions from sweat glands, which inhibit bacterial growth [sebum (unsaturated fatty acids) provides a protective film on the skin and inhibits growth], mucous membranes (saliva, tears, sweat, etc.) that contain antimicrobial proteins such as lysozyme, which breaks down bacterial cell walls, vibrissae (nose hair) filters microbes, dust, and pollutants within air, cilia in the respiratory system that sweep mucus with its trapped microbes out of the lungs and into the throat, and gastric juice, which is highly acidic, kills microbes in the stomach that enter through the nose and mouth. The second line of defense is meant to limit the spread of invaders in advance of specific immune responses (supports management to help ensure risk and controls are effectively managed) with 3 various strategies.
What is the lymph system?
The lymphatic system is an extensive network of vessels, nodes, and ducts that pass through almost all bodily tissues. It allows the circulation of a fluid called lymph through the body in a similar way to blood. The lymphatic system is essential for fluid balance, absorption of fatty acids in the stomach, and immune system regulation.
What is the major histocompatibility complex (MHC)?
The major histocompatibility complex, or MHC, is the mechanism the immune system uses to differentiate between self and foreign cells. It is a collection of glycoproteins that are displayed on the cell membranes of every body cell, and the MHC molecules display protein fragments from inside the cell. These molecular protein fragments are known as epitopes, and each individual has a highly unique (but not always, especially in the case of identical twins) set of MHC molecules. T-cells interact with MHC molecules and "read" the epitopes to ensure that foreign invaders are not present in the cells. There are three classes of MHC, but only MHC I and MHC II play a role in immunity:
What is erythropoiesis?
The production of red blood cells,which is located in the bone marrow.
What is the spleen?
The spleen is located about the left kidney and has essential functions: it fights invading germs in the blood (the spleen contains infection-fighting white blood cells) it controls the level of blood cells (white blood cells, red blood cells and platelets) it filters the blood and removes any old or damaged red blood cells (purifies the blood with the two main types of tissues; red and white pulp). It is also the largest collection of lymphoid tissue in the body.
What is part of the lymph system?
The spleen, the thymus, the tonsils, the lymph nodes and the fluid called "lymph".
What is the thymus?
The thymus is a specialized organ that is essential for T cell development, or in other words, it is the site of the T cell maturation. it is located behind the breastbone (sternum) and is in front and above the heart.
What are the tonsils?
The tonsils are part of the body's first line of defense (preventing germs from entering through the mouth and nose), and also help produce T cells. However, they do not have a significant function and are often removed due to inflammation. They are located in the pharynx.
Which type of white blood cells are present in the human immune system?
The two main types of phagocytic cells within the immune system are neutrophils and macrophages. Other phagocytic cells are monocytes, mast cells, and dendritic cells. Basophils and Eosinophils are also white blood cells, but are not phagocytes.
What happens when pathogens are engulfed by a phagocytic cell's vacuole?
The vacuole fuses with a lysosome (located within the phagocytic cell), leading to destruction of the invaders in two ways. First, gases produced in the lysosome poisons the engulfed pathogens. Second, lysozyme and other enzymes in the lysosome degrade the components of the pathogens.
What are scavengers within the body?
They remove dead cells and microorganisms.
What is a toll-like signaling?
Toll-like receptor (TLR) recognizes a molecular pattern characteristic of a group of pathogens. Lipopolysaccharide, flagellin, CpG DNA (DNA containing unmethylated CG sequences), and double-stranded (ds) RNA are all found in bacteria, fungi, or viruses, but not in animal cells. Together with other recognition and response factors, TLR proteins trigger internal innate immune defenses. . Each mammalian Toll-like receptor (TLR) binds to fragments of molecules characteristic of a set of pathogens. For example, TLR3, on the inner surface of vesicles formed by endocytosis, is the sensor for double-stranded RNA, a form of nucleic acid characteristic of certain viruses. Similarly, TLR4, located on immune cell plasma membranes, recognizes lipopolysaccharide, a type of molecule found on the surface of many bacteria
In the example a splinter, the following events occur as part of the inflammatory response:
1. Damaged cells released chemokines. 2. Mast cells, responding to chemkines, direct contact with the splinter, or bacteria, release histamine. 3. Histamine causes capillary endothelial cells to enlarge and move outwards, creating a swell in the capillary which encourages fluid collection. The capillary walls also become more porous. This process is called vasodilation. Vasodilation causes redness, temperature increase and swelling. The increase in temperature causes an increased metabolic rate in cells. Activated capillary endothelial cells also display adhesion molecules called selectins on the inner capillary surface. 4. Phagocytes, namely neutrophils, are attracted to, slowed down by, and roll along the wall due to the selectins. Chemicals in the bloodstream activate integrins, adhesion receptors on neutrophils. The integrins then bind to adhesion receptor molecules on the capillary endothelial cell surfaces. The accumulation and adhesion of leukocytes to the blood vessel walls is called margination or pavementing. 5. Phagocytes, namely neutrophils, are attracted to, slowed down by, and roll along the wall due to the selectins. Chemicals in the bloodstream activate integrins, adhesion receptors on neutrophils. The integrins then bind to adhesion receptor molecules on the capillary endothelial cell surfaces. The accumulation and adhesion of leukocytes to the blood vessel walls is called margination or pavementing. 6. Neutrophils and other phagocytes attack invading bacteria that have entered due to the splinter. Complement helps phagocytes engulf foreign cells, and stimulates additional histamine secretion by basophils.
What is a biochemical cascade?
A biochemical cascade, also known as a signaling cascade or signaling pathway, is a series of chemical reactions that occur within a biological cell when initiated by a stimulus. It ties in with the inflammatory response (and the immune system in general) because it often consists of reactions to certain stimuli which in turn cause more reactions. Signaling pathways like this can, again, be referred to as biochemical cascades.
What is the fluid called "lymph"?
A fluid called lymph circulates the lymphatic system. It is derived from interstitial fluid and carries bacteria to the lymph nodes, where they are destroyed by leukocytes. The lymph also transports fats coming from the organs in the digestive system.
What are pathogens?
A pathogen is a bacterium, virus, or other microorganism that can cause disease.
What are helper T cells?
A type of immune cell that stimulates killer T cells, macrophages, and B cells to make immune responses (to proliferate B cells and cytotoxic T cells).
What is MHC class I?
All nucleic cells in the body, which includes all cells except for erythrocytes, display MHC Class I protein fragments. Cytotoxic T-cells will dock their CD8 receptors to the MHC molecules, which allows the T-cell receptors to connect with the epitope. If the T-cell receptors fit the epitope, the cytotoxic T-cell will trigger apoptosis, which is programmed cell death. Otherwise, the cytotoxic T-cell will move on to another cell. This is how cytotoxic T-cells play a role in adaptive immunity, because the shape of the T-cell receptors varies for each antigen that T-cells encounter.
What are antigens?
Antigens are anything that causes an immune response which can be entire pathogens, like bacteria, viruses, fungi, and parasites, or smaller proteins that pathogens express. Antigens are also substances that bind to specific immune receptors and elicit an immune response, and are part of the non-self molecules. In other words, antigens are molecules, usually proteins or polysaccharides, that are identified as foreign to the body
What is autoimmunity?
Autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other body normal constituents (attacking self molecules). Any disease resulting from this type of immune response is termed an "autoimmune disease".
What is a B cell?
B cells originate and mature in bone marrow (think: "B" for bone). They respond to antigens using specialized proteins called antibodies on their plasma membrane surface.
What can be used to treat allergies?
Because allergies are caused by IgE (releasing histamine), it can be combated with antihistamine, or diphenhydramine.
What are chemokines?
Chemokines guide the movement of cells. Cells respond to certain chemokines by moving towards areas of higher concentrations of chemokines. In the immune system, they create a chemical gradient to attract neutrophils and other leucocytes to the wound site. In other words, they are best known for their ability to stimulate the migration of cells, most notably white blood cells (leukocytes).
What is clonal selection?
Clonal selection is when an antigen binds to a C cell or a nonself cell binds to a T cell, the B or T cell divides to produce many identical copies, which results in an increased number of the C or T cell that can respond to the specific antigen.
What are cytotoxic T cells (killer cells)?
Cytotoxic T cells or killer T cells destroys nonself cells by causing them to lyse (to lyse is to break apart a larger particle into smaller pieces).
What are dendritic cells?
Dendritic cells are the messengers between the innate and adaptive immune systems. Dendritic cells acquire and present antigens to lymphocytes to activate them.
What is molecular recognition?
Detection of nonself is accomplished by molecular recognition, in which receptor molecules bind specifically to molecules from foreign cells or viruses.
What are eosinophils?
Eosinophils, often found beneath mucosal surfaces, are short-lived and have a wide range of functions, including attacking parasites (extremely important) and helping with allergic responses. The proteins they make can be harmful to the body's own tissues as well as pathogens.
What is the usage of a fever?
Fevers are an increase in body temperature, and it is induced by substances that are called pyrogens. The increased temperature inhibits bacterial growth and increases the rate of tissue repair during an infection; it may also help certain types of immune cells function more efficiently (fever alters surface proteins on immune cells like lymphocytes to make them better able to travel via blood vessels to reach the site of infection).