Was this article helpful? Comparative Immunology, Microbiology and Infectious Diseases. There are two major subtypes of T cells: Antibodies can also neutralize challenges directly, by binding to bacterial toxins or by interfering with the receptors that viruses and bacteria use to infect cells. Not only does it make us happy by giving, Seratonin is released in those who receive our generosity and the recipient is happy as well. These mushrooms easily grow almost anywhere in the world as long as there are trees, making them one of the most common mushrooms found today.
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D - "To strengthen the immune system, one must address the needs of the whole body. A strong immune system is essential for health. It is a very complex system of the body, involving the skin, intestines, nasal mucosa, blood, lymph and many other organs and tissues. Factors that impair the immune system include nutrient deficiencies, contaminated air, water and food, unhealthful lifestyles and too much exposure to harmful microbes.
Other factors that weaken the immune system are negative attitudes and emotions and the presence of toxic metals, toxic chemicals and biological toxins in the body. Others are sluggish metabolism, lack of rest and sleep, excessive stress or too much exercise. As these causative factors are removed or corrected, the immune system improves. The human and animal immune system is a truly amazing constellation of responses to attacks from outside the body.
It has many facets, a number of which can change to optimize the response to these unwanted intrusions. Towards the end of Louis Pasteur 's life, he confessed that germs may not be the cause of disease after all, but may simply be another symptom of disease.
He had come to realize that germs seem to lead to illness primarily when the person's immune and defense system, what biologists call "host resistance" is not strong enough to combat them. The "cause" of disease is not simply a bacteria but also the factors that compromise host resistance, including the person's hereditary endowment, his nutritional state, the stresses in his life, and his psychological state. The term "autoimmune disease" refers to a varied group of more than 80 serious, chronic illnesses that involve almost every human organ system.
It includes diseases of the nervous, gastrointestinal, and endocrine systems as well as skin and other connective tissues, eyes blood, and blood vessel. In all of these diseases, the underlying problem is similar--the body's immune system becomes misdirected, attacking the very organs it was designed to protect.
The immune system is a scapegoat for a variety of ills in this wide-ranging but tendentious guide to approaching diseases like lupus, Crohn's disease, MS, and rheumatoid arthritis. Every mother human or mammal that breast feeds her baby, passes all of the immunity gained throughout her lifetime on to her infant. A healthy immune system removes toxins and damaged cellular material. This compelling memoir of a life-or-death struggle with immune deficiency and the medical profession illuminates that dark side of medicine where unfounded beliefs substitute for scientific knowledge.
You must read this book if you have unexplained medical problems such as debilitating fatigue and pain -you can't think clearly because of brain fog - your doctor implies that it's all in your head - you want help and inspiration to find the cause and a solution.
Winning My Battle Against Toxins, Illness and The Medical Establishment is the personal and compelling story of Judith Lopez and her experiences with medical mismanagement and malpractice. Judith documents her struggle with a mystery malady that was life threatening. All the while her doctors sought to discount chronic fatigue syndrome, yeast syndrome, and environmental illnesses as merely sociogenic problems, the result of a mass hysteria or psychosomatic illness.
After a twenty year battle with an illness the medical community proclaimed to be non-existent, Judith finally connected with Doctor Vincent Marinkovich, a Stanford professor and authority on clinical immunology and allergy, who was able to understand and treat her symptoms.
Immune Dysfunction is a powerful and engaging medical memoir and highly recommended reading for anyone suffering from any form of environmentally generated illness whose physicians are trying to palm off as a form of hysteria or mental illness, as well as medical students, health workers, and practicing physicians concerned with the proper diagnosis and treatment of the rapidly growing numbers of men, women, and children who are experiencing environmentally driven immune system dysfunctions.
Unprecedented exposure to chemical contaminants, pollution, toxic products and stress has increased unhealthy conditions, from arthritis and cancer to heart disease, and even the symptoms of aging. Its no wonder so many people are suffering from fatigue and chronic illness, as well as chronic infections with viruses, bacteria and fungi. You can learn how to protect yourself from the forces that can damage your body and wear down your immune system.
Standard Western Medicine strives to suppress the immune response , working against the body. If there is a fever, lower it, if inflammation is present provide steroids to remove it and of course if Western Medicine thinks a bacteria or virus is present or doesn't know what is wrong, a dose of antibiotics is provided.
This way of doing things can be effective in the immediate term, and important in life threatening situations, but potentially devastating in the long term especially when over-used. Because, what eventually happens, is that immune system becomes weak and ineffective or damaged and over-reactive and disease is pushed deeper into the body to come back stronger and more difficult to get rid of at a later date. A Holistic health care practitioner will not want to suppress symptoms unless they view it to be absolutely necessary, because those symptoms are a sign the immune system is working and doing its job.
Alexander Fleming, the scientist who discovered penicillin, cautioned against the overuse of antibiotics. Although the suppressive therapies are hard on the body, they do not compare with the rampant idiocy of using antibiotics for viral infections. Thankfully some measure of sanity appears to be returning to the medical profession.
More and more doctors are avoiding prescribing antibiotics for colds and flus. Several critical observations must be made here.
First, antibiotics are totally ineffective against viruses. The excuse most often heard for prescribing antibiotics in a viral illness is to prophylactically protect the body against a secondary bacterial infection.
This is an idea proven to be false decades ago. In the United States, of the 5 most common antibiotics prescribed, three are broad spectrum.
Second, the basis of antibiotics is mold. Through millions of years of evolution, bacteria and mold have coexisted in nature - in the soil, plants and animals. When one of them developed an evolutionary edge over the other and began to shift the balance in favor of itself, the other must have rapidly learned to defend itself against this new attack.
If this were not true, we would only have either bacteria or molds but not both. By using mold, we thought we could slay one step ahead of bacteria in the evolutionary scale because we're so smart. Well, the yolk is on us, the bacteria are winning, and at a record pace.
So in our attempt to wipe out bacteria, we forced them into a revolutionary evolutionary change and we damaged our immunity so badly that we become easy prey for viruses. Additional side effects of antibiotics are immune suppression and the increased susceptibility to parasites. The long term effects of the breakdown of the immune system can be seen in increased infections, auto-immune disorders and tumor formation. In "Beyond Antibiotics" Drs. Schmidt, Smith, and Sehnert explore the problems presented by the overuse of these drugs.
More importantly, they show how to build immunity, improve resistance to infections, and avoid antibiotics when possible. The scientific community and the general public have ignored the insights of the late Pasteur and have ignored the importance of host resistance in preventing illness more on Louis Pasteur.
The SARS epidemic is only one of an ongoing series of new emerging diseases. Lawrence Wilson -" Factors that impair the immune system include nutrient deficiencies, contaminated air, water and food, unhealthful lifestyles and too much exposure to harmful microbes. Your immune system is constantly on the prowl for pathogens and foreign antigen agents of cellular damage, toxicity and disease.
These antigens include viruses, bacteria, parasites, fungi and even pre-cancerous cells. To neutralize these pathogens, the body needs a ready supply of glutathione. We cant avoid illness and aging altogether, but by keeping our intracellular glutathione levels elevated, we also keep our immune system on full alert and fully armed.
Wulf Droge MD - "The human immune system is extremely dependent on adequate glutathione levels to perform properly. Even a partial depletion of the intracellular glutathione pool has a dramatic consequence for the process of blast transformation and proliferation, and for the generation of cytotoxic T cells.
We have all heard stories of apparently miraculous recoveries from terminal cancer, but are any of these accounts true? Medical journals have published thousands of case histories about seemingly incurable patients who have seen their cancers disappear in the absence of medical treatment.
These examples of spontaneous regression demonstrate the power of the human immune system. It can cure cancer. Studies confirm that the eight essential biologically active sugars can accomplish amazing results. The following are just a few examples of the exciting possibilities of Glyconutrition:. Homeopathy as a properly practiced art , stimulates an accelerated immune system response. Back in the early 's homeopathy carved out a reputation for itself with the extraordinary results its treating patients during epidemics.
The battle of Leipzig in caused an outbreak of typhus which Hahnemann treated. During the winter of a cholera epidemic broke out in Europe. This fact has been established by basic physiology research in the s and the s. Your gut, your digestive wall, is the biggest and the most important immune organ in your body. There is a very tight conversation and a relationship going on between the gut flora microbiome that lives inside your digestive system, and your immune system Your gut flora the state of the gut flora and the composition of microbes in your gut flora has a profound effect on what forms of immune cells you will be producing on any given day, what they're going to be doing, and how balanced your immune system is.
Natural Treatment for Autism, Dyspraxia, A. The intestinal lining becomes porous when it is inflamed, oxidized, toxic, and lacking in energy. This is called 'leaky gut.
One of the many problems that result is a priming of the "systemic immune system" to attack molecules and tissues it should not be attacking. This means that the immune system you are more familiar with white cells, antibodies, immunoglobulins, etc.
This is the main reason why we develop "autoimmune" problems, such as arthritis, lupus, thyroiditis, etc. Trends in Immunology ; After all, it also needs energy to function.
This also means that being obese and prediabetic compromises our immune system. By improving insulin resistance improves the immune system. Enzymes are proteins that facilitate chemical reactions in living organisms. They are required for every single chemical action that takes place in your body. All of your tissues, muscles, bones, organs and cells are run by enzymes. Your digestive system, immune system, bloodstream, liver, kidneys, spleen and pancreas, as well as your ability to see, think, feel and breathe, all depend on enzymes.
Systemic enzymes , sometimes called metabolic or proteolytic enzymes , are produced by the pancreas to repair the body In fact, they are a necessary component of all other functions in the body besides digestion, and your body is unable to produce enough of them because we eat cooked foods. Animal studies have shown that an increase in fat intake can decrease the number of natural killer NK cells found in the blood and spleen. NK cells are an integral part of the natural immune response to virus infections and certain types of cancer.
Researchers at Oxford University now report that fish oil significantly decreases NK cell activity in healthy human subjects. Their clinical trial involved 48 men and women aged 55 to 75 years. The participants were randomized to receive one of six supplements for 12 weeks.
The supplements were all provided in the form of capsules, three of which were to be taken with each meal. All the participants had blood samples taken four weeks before start of supplementation, immediately before start of supplementation, and then every four weeks during the trial as well as after a four-week washout period.
The researchers found no changes in killer cell activity except in the group taking fish oil. Here they observed an average decline of 20 per cent after 8 weeks and 48 per cent after 12 weeks.
The decline was completely reversed after the washout period. The researchers conclude that an excessive EPA intake could have adverse effects for people at risk of viral infections and some cancers. The British researchers' speculation about fish oils perhaps affecting the effectiveness of NK cells in killing cancer cells is at odds with the results of many other studies. There are at least a dozen studies that show a clear protective effect of fish or fish oil against breast, colon, and prostate cancer.
American Journal of Clinical Nutrition, Vol. Its been around for thousands of years. Every traditional healing culture in the world has a ginseng or ginseng-type plant in its medicine chest. Daily ginseng was a necessary matter of life throughout all of Chinas long history.
At the turn of the 20th century, virtually every Chinese person used ginseng to some extent for their well being, especially as a wellness tonic. Ginseng was also highly esteemed by every Native American culture. At the Institute of Traditional Chinese Medicine in Jilin Province where ginseng is grown , researchers in the pharmacology department evaluated the effects of ginseng on immune responses.
The immune responses of mice were tested with different dosages of extracts obtained either from the leaf or the root of ginseng. Significant changes in the response of the reticuloendothelial RES system were found, especially with moderate doses of the root extracts. They secrete chemical mediators that are involved in defending against parasites and play a role in allergic reactions, such as asthma.
Natural killer cells , or NK cells, are lymphocytes and a component of the innate immune system which does not directly attack invading microbes. It is now known that the MHC makeup on the surface of those cells is altered and the NK cells become activated through recognition of "missing self". Normal body cells are not recognized and attacked by NK cells because they express intact self MHC antigens. The adaptive immune system evolved in early vertebrates and allows for a stronger immune response as well as immunological memory, where each pathogen is "remembered" by a signature antigen.
Antigen specificity allows for the generation of responses that are tailored to specific pathogens or pathogen-infected cells. The ability to mount these tailored responses is maintained in the body by "memory cells".
Should a pathogen infect the body more than once, these specific memory cells are used to quickly eliminate it. The cells of the adaptive immune system are special types of leukocytes, called lymphocytes. B cells and T cells are the major types of lymphocytes and are derived from hematopoietic stem cells in the bone marrow. Both B cells and T cells carry receptor molecules that recognize specific targets.
T cells recognize a "non-self" target, such as a pathogen, only after antigens small fragments of the pathogen have been processed and presented in combination with a "self" receptor called a major histocompatibility complex MHC molecule. There are two major subtypes of T cells: In addition there are regulatory T cells which have a role in modulating immune response. These two mechanisms of antigen presentation reflect the different roles of the two types of T cell.
In contrast, the B cell antigen-specific receptor is an antibody molecule on the B cell surface, and recognizes whole pathogens without any need for antigen processing. Each lineage of B cell expresses a different antibody, so the complete set of B cell antigen receptors represent all the antibodies that the body can manufacture.
Killer T cells are a sub-group of T cells that kill cells that are infected with viruses and other pathogens , or are otherwise damaged or dysfunctional. Recognition of this MHC: The T cell then travels throughout the body in search of cells where the MHC I receptors bear this antigen.
When an activated T cell contacts such cells, it releases cytotoxins , such as perforin , which form pores in the target cell's plasma membrane , allowing ions , water and toxins to enter.
The entry of another toxin called granulysin a protease induces the target cell to undergo apoptosis. Helper T cells regulate both the innate and adaptive immune responses and help determine which immune responses the body makes to a particular pathogen.
They instead control the immune response by directing other cells to perform these tasks. Helper T cells have a weaker association with the MHC: Helper T cell activation also requires longer duration of engagement with an antigen-presenting cell.
Cytokine signals produced by helper T cells enhance the microbicidal function of macrophages and the activity of killer T cells. On the other hand, the various subsets are also part of the innate immune system, as restricted TCR or NK receptors may be used as pattern recognition receptors.
A B cell identifies pathogens when antibodies on its surface bind to a specific foreign antigen. This combination of MHC and antigen attracts a matching helper T cell, which releases lymphokines and activates the B cell. These antibodies circulate in blood plasma and lymph , bind to pathogens expressing the antigen and mark them for destruction by complement activation or for uptake and destruction by phagocytes.
Antibodies can also neutralize challenges directly, by binding to bacterial toxins or by interfering with the receptors that viruses and bacteria use to infect cells. Evolution of the adaptive immune system occurred in an ancestor of the jawed vertebrates.
Many of the classical molecules of the adaptive immune system e. However, a distinct lymphocyte -derived molecule has been discovered in primitive jawless vertebrates , such as the lamprey and hagfish. These animals possess a large array of molecules called Variable lymphocyte receptors VLRs that, like the antigen receptors of jawed vertebrates, are produced from only a small number one or two of genes. These molecules are believed to bind pathogenic antigens in a similar way to antibodies, and with the same degree of specificity.
When B cells and T cells are activated and begin to replicate, some of their offspring become long-lived memory cells. Throughout the lifetime of an animal, these memory cells remember each specific pathogen encountered and can mount a strong response if the pathogen is detected again.
This is "adaptive" because it occurs during the lifetime of an individual as an adaptation to infection with that pathogen and prepares the immune system for future challenges.
Immunological memory can be in the form of either passive short-term memory or active long-term memory. Newborn infants have no prior exposure to microbes and are particularly vulnerable to infection. Several layers of passive protection are provided by the mother. During pregnancy , a particular type of antibody, called IgG , is transported from mother to baby directly through the placenta , so human babies have high levels of antibodies even at birth, with the same range of antigen specificities as their mother.
This passive immunity is usually short-term, lasting from a few days up to several months. In medicine, protective passive immunity can also be transferred artificially from one individual to another via antibody-rich serum. Long-term active memory is acquired following infection by activation of B and T cells. Active immunity can also be generated artificially, through vaccination. The principle behind vaccination also called immunization is to introduce an antigen from a pathogen in order to stimulate the immune system and develop specific immunity against that particular pathogen without causing disease associated with that organism.
With infectious disease remaining one of the leading causes of death in the human population, vaccination represents the most effective manipulation of the immune system mankind has developed. Most viral vaccines are based on live attenuated viruses, while many bacterial vaccines are based on acellular components of micro-organisms, including harmless toxin components.
The immune system is a remarkably effective structure that incorporates specificity, inducibility and adaptation. Failures of host defense do occur, however, and fall into three broad categories: Immunodeficiencies occur when one or more of the components of the immune system are inactive.
The ability of the immune system to respond to pathogens is diminished in both the young and the elderly , with immune responses beginning to decline at around 50 years of age due to immunosenescence. Additionally, the loss of the thymus at an early age through genetic mutation or surgical removal results in severe immunodeficiency and a high susceptibility to infection. Immunodeficiencies can also be inherited or ' acquired'.
AIDS and some types of cancer cause acquired immunodeficiency. Overactive immune responses comprise the other end of immune dysfunction, particularly the autoimmune disorders. Here, the immune system fails to properly distinguish between self and non-self, and attacks part of the body.
Under normal circumstances, many T cells and antibodies react with "self" peptides. Hypersensitivity is an immune response that damages the body's own tissues.
Type I hypersensitivity is an immediate or anaphylactic reaction, often associated with allergy. Symptoms can range from mild discomfort to death.
Type I hypersensitivity is mediated by IgE , which triggers degranulation of mast cells and basophils when cross-linked by antigen. This is also called antibody-dependent or cytotoxic hypersensitivity, and is mediated by IgG and IgM antibodies. Type IV reactions are involved in many autoimmune and infectious diseases, but may also involve contact dermatitis poison ivy.
These reactions are mediated by T cells , monocytes , and macrophages. Inflammation is one of the first responses of the immune system to infection,  but it can appear without known cause. It is likely that a multicomponent, adaptive immune system arose with the first vertebrates , as invertebrates do not generate lymphocytes or an antibody-based humoral response.
Immune systems appear even in the structurally most simple forms of life, with bacteria using a unique defense mechanism, called the restriction modification system to protect themselves from viral pathogens, called bacteriophages.
Pattern recognition receptors are proteins used by nearly all organisms to identify molecules associated with pathogens. Antimicrobial peptides called defensins are an evolutionarily conserved component of the innate immune response found in all animals and plants, and represent the main form of invertebrate systemic immunity. Ribonucleases and the RNA interference pathway are conserved across all eukaryotes , and are thought to play a role in the immune response to viruses. Unlike animals, plants lack phagocytic cells, but many plant immune responses involve systemic chemical signals that are sent through a plant.
Systemic acquired resistance SAR is a type of defensive response used by plants that renders the entire plant resistant to a particular infectious agent. Another important role of the immune system is to identify and eliminate tumors. This is called immune surveillance. The transformed cells of tumors express antigens that are not found on normal cells. To the immune system, these antigens appear foreign, and their presence causes immune cells to attack the transformed tumor cells.
The antigens expressed by tumors have several sources;  some are derived from oncogenic viruses like human papillomavirus , which causes cervical cancer ,  while others are the organism's own proteins that occur at low levels in normal cells but reach high levels in tumor cells.
One example is an enzyme called tyrosinase that, when expressed at high levels, transforms certain skin cells e. The main response of the immune system to tumors is to destroy the abnormal cells using killer T cells, sometimes with the assistance of helper T cells. This allows killer T cells to recognize the tumor cell as abnormal.
Clearly, some tumors evade the immune system and go on to become cancers. Paradoxically, macrophages can promote tumor growth  when tumor cells send out cytokines that attract macrophages, which then generate cytokines and growth factors such as tumor-necrosis factor alpha that nurture tumor development or promote stem-cell-like plasticity.
The immune system is involved in many aspects of physiological regulation in the body. The immune system interacts intimately with other systems, such as the endocrine   and the nervous    systems. The immune system also plays a crucial role in embryogenesis development of the embryo , as well as in tissue repair and regeneration. Hormones can act as immunomodulators , altering the sensitivity of the immune system.
For example, female sex hormones are known immunostimulators of both adaptive  and innate immune responses. By contrast, male sex hormones such as testosterone seem to be immunosuppressive. When a T-cell encounters a foreign pathogen , it extends a vitamin D receptor. This is essentially a signaling device that allows the T-cell to bind to the active form of vitamin D , the steroid hormone calcitriol.
T-cells have a symbiotic relationship with vitamin D. Not only does the T-cell extend a vitamin D receptor, in essence asking to bind to the steroid hormone version of vitamin D, calcitriol, but the T-cell expresses the gene CYP27B1 , which is the gene responsible for converting the pre-hormone version of vitamin D, calcidiol into the steroid hormone version, calcitriol. Only after binding to calcitriol can T-cells perform their intended function. Other immune system cells that are known to express CYP27B1 and thus activate vitamin D calcidiol, are dendritic cells , keratinocytes and macrophages.
It is conjectured that a progressive decline in hormone levels with age is partially responsible for weakened immune responses in aging individuals. As people age, two things happen that negatively affect their vitamin D levels. First, they stay indoors more due to decreased activity levels. This means that they get less sun and therefore produce less cholecalciferol via UVB radiation.
Second, as a person ages the skin becomes less adept at producing vitamin D. The immune system is affected by sleep and rest,  and sleep deprivation is detrimental to immune function. When suffering from sleep deprivation, active immunizations may have a diminished effect and may result in lower antibody production, and a lower immune response, than would be noted in a well-rested individual. Additionally, proteins such as NFIL3 , which have been shown to be closely intertwined with both T-cell differentiation and our circadian rhythms, can be affected through the disturbance of natural light and dark cycles through instances of sleep deprivation, shift work, etc.
As a result, these disruptions can lead to an increase in chronic conditions such as heart disease, chronic pain, and asthma. In addition to the negative consequences of sleep deprivation, sleep and the intertwined circadian system have been shown to have strong regulatory effects on immunological functions affecting both the innate and the adaptive immunity. First, during the early slow-wave-sleep stage, a sudden drop in blood levels of cortisol , epinephrine , and norepinephrine induce increased blood levels of the hormones leptin, pituitary growth hormone, and prolactin.
These signals induce a pro-inflammatory state through the production of the pro-inflammatory cytokines interleukin-1, interleukin , TNF-alpha and IFN-gamma. These cytokines then stimulate immune functions such as immune cells activation, proliferation, and differentiation. It is during this time that undifferentiated, or less differentiated, like naïve and central memory T cells, peak i.
This milieu is also thought to support the formation of long-lasting immune memory through the initiation of Th1 immune responses. In contrast, during wake periods differentiated effector cells, such as cytotoxic natural killer cells and CTLs cytotoxic T lymphocytes , peak in order to elicit an effective response against any intruding pathogens. As well during awake active times, anti-inflammatory molecules, such as cortisol and catecholamines , peak. There are two theories as to why the pro-inflammatory state is reserved for sleep time.
First, inflammation would cause serious cognitive and physical impairments if it were to occur during wake times. Second, inflammation may occur during sleep times due to the presence of melatonin.
Inflammation causes a great deal of oxidative stress and the presence of melatonin during sleep times could actively counteract free radical production during this time.
Overnutrition is associated with diseases such as diabetes and obesity , which are known to affect immune function. More moderate malnutrition, as well as certain specific trace mineral and nutrient deficiencies, can also compromise the immune response. Foods rich in certain fatty acids may foster a healthy immune system. The immune system, particularly the innate component, plays a decisive role in tissue repair after an insult.
The plasticity of immune cells and the balance between pro-inflammatory and anti-inflammatory signals are crucial aspects of efficient tissue repair. According to one hypothesis, organisms that can regenerate could be less immunocompetent than organisms that cannot regenerate. The immune response can be manipulated to suppress unwanted responses resulting from autoimmunity, allergy, and transplant rejection , and to stimulate protective responses against pathogens that largely elude the immune system see immunization or cancer.
Immunosuppressive drugs are used to control autoimmune disorders or inflammation when excessive tissue damage occurs, and to prevent transplant rejection after an organ transplant. Anti-inflammatory drugs are often used to control the effects of inflammation. Glucocorticoids are the most powerful of these drugs; however, these drugs can have many undesirable side effects , such as central obesity , hyperglycemia , osteoporosis , and their use must be tightly controlled.
Cytotoxic drugs inhibit the immune response by killing dividing cells such as activated T cells. However, the killing is indiscriminate and other constantly dividing cells and their organs are affected, which causes toxic side effects. Cancer immunotherapy covers the medical ways to stimulate the immune system to attack cancer tumours. Immunology is strongly experimental in everyday practice but is also characterized by an ongoing theoretical attitude.
Many theories have been suggested in immunology from the end of the nineteenth century up to the present time. The end of the 19th century and the beginning of the 20th century saw a battle between "cellular" and "humoral" theories of immunity. In the mids, Frank Burnet , inspired by a suggestion made by Niels Jerne ,  formulated the clonal selection theory CST of immunity. More recently, several theoretical frameworks have been suggested in immunology, including " autopoietic " views,  "cognitive immune" views,  the " danger model " or "danger theory" ,  and the "discontinuity" theory.
This limits the effectiveness of drugs based on larger peptides and proteins which are typically larger than Da. In some cases, the drug itself is not immunogenic, but may be co-administered with an immunogenic compound, as is sometimes the case for Taxol. Computational methods have been developed to predict the immunogenicity of peptides and proteins, which are particularly useful in designing therapeutic antibodies, assessing likely virulence of mutations in viral coat particles, and validation of proposed peptide-based drug treatments.
Early techniques relied mainly on the observation that hydrophilic amino acids are overrepresented in epitope regions than hydrophobic amino acids;  however, more recent developments rely on machine learning techniques using databases of existing known epitopes, usually on well-studied virus proteins, as a training set.
The success of any pathogen depends on its ability to elude host immune responses. Therefore, pathogens evolved several methods that allow them to successfully infect a host, while evading detection or destruction by the immune system. These proteins are often used to shut down host defenses.
An evasion strategy used by several pathogens to avoid the innate immune system is to hide within the cells of their host also called intracellular pathogenesis. Here, a pathogen spends most of its life-cycle inside host cells, where it is shielded from direct contact with immune cells, antibodies and complement. Some examples of intracellular pathogens include viruses, the food poisoning bacterium Salmonella and the eukaryotic parasites that cause malaria Plasmodium falciparum and leishmaniasis Leishmania spp.
Other bacteria, such as Mycobacterium tuberculosis , live inside a protective capsule that prevents lysis by complement. Such biofilms are present in many successful infections, e.
The mechanisms used to evade the adaptive immune system are more complicated. This is called antigenic variation. An example is HIV, which mutates rapidly, so the proteins on its viral envelope that are essential for entry into its host target cell are constantly changing.
These frequent changes in antigens may explain the failures of vaccines directed at this virus. In HIV, the envelope that covers the virion is formed from the outermost membrane of the host cell; such "self-cloaked" viruses make it difficult for the immune system to identify them as "non-self" structures.
From Wikipedia, the free encyclopedia. This is the latest accepted revision , reviewed on 13 August A biological system that protects an organism against disease. Cataphylaxis Clonal selection Hapten Human physiology Immune network theory Immune system receptors ImmunoGrid , a project to model the mammalian, and specifically human, immune system using Grid technologies Immunoproteomics Immunostimulator Original antigenic sin Plant disease resistance Polyclonal response Tumor antigens Vaccine-naive Mucosal immunology.
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