Immune response in the context of Toxin

Injury is physiological damage to the living tissue of any organism, whether in humans, in other animals, or in plants.

Injuries can be caused in many ways, including mechanically with penetration by sharp objects such as teeth or with blunt objects, by heat or cold, or by venoms and biotoxins. Injury prompts an inflammatory response in many taxa of animals; this prompts wound healing. In both plants and animals, substances are often released to help to occlude the wound, limiting loss of fluids and the entry of pathogens such as bacteria. Many organisms secrete antimicrobial chemicals which limit wound infection; in addition, animals have a variety of immune responses for the same purpose. Both plants and animals have regrowth mechanisms which may result in complete or partial healing over the injury. Cells too can repair damage to a certain degree.

A chloroplast (/ˈklɔːrəˌplæst, -plɑːst/) is a type of organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. Chloroplasts have a high concentration of chlorophyll pigments which capture the energy from sunlight and convert it to chemical energy and release oxygen. The chemical energy created is then used to make sugar and other organic molecules from carbon dioxide in a process called the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in some unicellular algae, up to 100 in plants like Arabidopsis and wheat.

Chloroplasts are highly dynamic—they circulate and are moved around within cells. Their behavior is strongly influenced by environmental factors like light color and intensity. Chloroplasts cannot be made anew by the plant cell and must be inherited by each daughter cell during cell division, which is thought to be inherited from their ancestor—a photosynthetic cyanobacterium that was engulfed by an early eukaryotic cell.

An allergy is an exaggerated immune response where the body mistakenly identifies an ordinarily harmless allergen as a threat. Allergic reactions give rise to allergic diseases such as hay fever, allergic conjunctivitis, allergic asthma, atopic dermatitis, food allergies, and anaphylaxis. Symptoms of allergic diseases may include red eyes, an itchy rash, sneezing, coughing, a runny nose, shortness of breath, or swelling.

Common allergens include pollen, certain foods, metals, insect stings, and medications. The development of allergies is due to genetic and environmental factors. The mechanism of allergic reactions involves immunoglobulin E antibodies (IgE) binding to an allergen and then to a receptor on mast cells or basophils, where they trigger the release of inflammatory chemicals such as histamine. Diagnosis is typically based on a person's medical history. Further testing of the skin or blood may be useful in certain cases. Positive tests, however, may not necessarily mean there is a significant allergy to the substance in question.

An allergen is an otherwise harmless substance that triggers an allergic reaction in sensitive individuals by stimulating an immune response.

In technical terms, an allergen is an antigen that is capable of stimulating a type-I hypersensitivity reaction in atopic individuals through immunoglobulin E (IgE) responses. Most humans mount significant immunoglobulin E responses only as a defense against parasitic infections. However, some individuals may respond to many common environmental antigens. In atopic individuals, non-parasitic antigens stimulate inappropriate IgE production, leading to type I hypersensitivity.

The common cold, or the cold, is a viral infectious disease of the upper respiratory tract that primarily affects the respiratory mucosa of the nose, throat, sinuses, and larynx. Signs and symptoms may appear in as little as two days after exposure to the virus. These may include coughing, sore throat, runny nose, sneezing, headache, fatigue, and fever. People usually recover in seven to ten days, but some symptoms may last up to three weeks. Occasionally, those with other health problems may develop pneumonia.

Well over 200 virus strains are implicated in causing the common cold, with rhinoviruses, coronaviruses, adenoviruses and enteroviruses being the most common. They spread through the air or indirectly through contact with objects in the environment, followed by transfer to the mouth or nose. Risk factors include going to child care facilities, not sleeping well, and psychological stress. The symptoms are mostly due to the body's immune response to the infection rather than to tissue destruction by the viruses themselves. The symptoms of influenza are similar to those of a cold, although usually more severe and less likely to include a runny nose.

Eicosanoids are signaling molecules made by the enzymatic or non-enzymatic oxidation of arachidonic acid or other polyunsaturated fatty acids (PUFAs) that are, similar to arachidonic acid, around 20 carbon units in length. Eicosanoids are a sub-category of oxylipins, i.e. oxidized fatty acids of diverse carbon units in length, and are distinguished from other oxylipins by their overwhelming importance as cell signaling molecules. Eicosanoids function in diverse physiological systems and pathological processes such as: mounting or inhibiting inflammation, allergy, fever and other immune responses; regulating the abortion of pregnancy and normal childbirth; contributing to the perception of pain; regulating cell growth; controlling blood pressure; and modulating the regional flow of blood to tissues. In performing these roles, eicosanoids most often act as autocrine signaling agents to impact their cells of origin or as paracrine signaling agents to impact cells in the proximity of their cells of origin. Some eicosanoids, such as prostaglandins, may also have endocrine roles as hormones to influence the function of distant cells.

There are multiple subfamilies of eicosanoids, including most prominently the prostaglandins, thromboxanes, leukotrienes, lipoxins, resolvins, and eoxins. For each subfamily, there is the potential to have at least 4 separate series of metabolites, two series derived from the ω−6 PUFAs arachidonic and dihomo-gamma-linolenic acids, one series derived from the ω−3 PUFA eicosapentaenoic acid, and one series derived from the ω−9 PUFA mead acid. This subfamily distinction is important. Mammals, including humans, are unable to convert ω−6 into ω−3 PUFA. In consequence, tissue levels of the ω−6 and ω−3 PUFAs and their corresponding eicosanoid metabolites link directly to the amount of dietary ω−6 versus ω−3 PUFAs consumed. Since certain of the ω−6 and ω−3 PUFA series of metabolites have almost diametrically opposing physiological and pathological activities, it has often been suggested that the deleterious consequences associated with the consumption of ω−6 PUFA-rich diets reflects excessive production and activities of ω−6 PUFA-derived eicosanoids, while the beneficial effects associated with the consumption of ω−3 PUFA-rich diets reflect the excessive production and activities of ω−3 PUFA-derived eicosanoids. In this view, the opposing effects of ω−6 PUFA-derived and ω−3 PUFA-derived eicosanoids on key target cells underlie the detrimental and beneficial effects of ω−6 and ω−3 PUFA-rich diets on inflammation and allergy reactions, atherosclerosis, hypertension, cancer growth, and a host of other processes.

Circumventricular organs (CVOs) (circum-: around ; ventricular: of ventricle) are structures in the brain characterized by their extensive and highly permeable capillaries, unlike those in the rest of the brain where there exists a blood–brain barrier (BBB) at the capillary level. Although the term "circumventricular organs" was originally proposed in 1958 by Austrian anatomist Helmut O. Hofer concerning structures around the brain ventricular system, the penetration of blood-borne dyes into small specific CVO regions was discovered in the early 20th century. The permeable CVOs enabling rapid neurohumoral exchange include the subfornical organ (SFO), the area postrema (AP), the vascular organ of lamina terminalis (VOLT — also known as the organum vasculosum of the lamina terminalis (OVLT)), the median eminence, the pituitary neural lobe, and the pineal gland.

The circumventricular organs are midline structures around the third and fourth ventricles that are in contact with blood and cerebrospinal fluid, and they facilitate special types of communication between the central nervous system and peripheral blood. Additionally, they are an integral part of neuroendocrine function. Highly permeable capillaries allow the CVOs to act as an alternative route for peptides and hormones in the neural tissue to sample from and secrete to circulating blood. CVOs also have roles in body fluid regulation, cardiovascular functions, immune responses, thirst, feeding behavior and reproductive behavior.

Glycolipids (/ˈɡlaɪkoʊˌlɪpɪdz/) are lipids with a carbohydrate attached by a glycosidic (covalent) bond. Their role is to maintain the stability of the cell membrane and to facilitate cellular recognition, which is crucial to the immune response and in the connections that allow cells to connect to one another to form tissues. Glycolipids are found on the surface of all eukaryotic cell membranes, where they extend from the phospholipid bilayer into the extracellular environment.

In immunology, an antigen (Ag) is a molecule, or portion thereof, that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response.

Antigens can be proteins, peptides (amino acid chains), polysaccharides (chains of simple sugars), lipids, or nucleic acids. Antigens exist on normal cells, cancer cells, parasites, viruses, fungi, and bacteria.

Embryonic stem cells (ESCs) are pluripotent stem cells derived from the inner cell mass of a blastocyst, an early-stage pre-implantation embryo. Human embryos reach the blastocyst stage 4–5 days post fertilization, at which time they consist of 50–150 cells. Isolating the inner cell mass (embryoblast) using immunosurgery results in destruction of the blastocyst, a process which raises ethical issues, including whether or not embryos at the pre-implantation stage have the same moral considerations as embryos in the post-implantation stage of development.

Researchers focus heavily on the therapeutic potential of embryonic stem cells, with clinical use being the goal for many laboratories. Potential uses include the treatment of diabetes and heart disease. The cells are studied to be used as clinical therapies, models of genetic disorders, and cellular/DNA repair. However, adverse effects in the research and clinical processes such as tumors and unwanted immune responses have also been reported.

Cellular immunity, also known as cell-mediated immunity, is an immune response that does not rely on the production of antibodies. Rather, cell-mediated immunity is the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.

Immunological memory is the ability of the immune system to quickly and specifically recognize an antigen that the body has previously encountered and initiate a corresponding immune response. Generally, they are secondary, tertiary and other subsequent immune responses to the same antigen. The adaptive immune system and antigen-specific receptor generation (TCR, antibodies) are responsible for adaptive immune memory.

After the inflammatory immune response to danger-associated antigen, some of the antigen-specific T cells and B cells persist in the body and become long-living memory T and B cells. After the second encounter with the same antigen, they recognize the antigen and mount a faster and more robust response. Immunological memory is the basis of vaccination. Emerging resources show that even the innate immune system can initiate a more efficient immune response and pathogen elimination after the previous stimulation with a pathogen, respectively with PAMPs or DAMPs. Innate immune memory (also called trained immunity) is neither antigen-specific nor dependent on gene rearrangement, but the different response is caused by changes in epigenetic programming and shifts in cellular metabolism. Innate immune memory was observed in invertebrates as well as in vertebrates.

Latex allergy is a medical term encompassing a range of allergic reactions to the proteins present in natural rubber latex. It generally develops after repeated exposure to products containing natural rubber latex. When latex-containing medical devices or supplies come in contact with mucous membranes, the membranes may absorb latex proteins. In some susceptible people, the immune system produces antibodies that react immunologically with these antigenic proteins. Many items contain or are made from natural rubber, including shoe soles, pen grips, hot water bottles, elastic bands, rubber gloves, condoms, baby-bottle nipples, and balloons; consequently, there are many possible routes of exposure that may trigger a reaction. People with latex allergies may also have or develop allergic reactions to some fruits, such as bananas.

Neurocysticercosis (NCC) is a parasitic infection of the nervous system caused by the larvae of the tapeworm Taenia solium, also known as the "pork tapeworm". The disease is primarily transmitted through direct contact with human feces, often through the consumption of food or water containing Taenia solium eggs. These eggs hatch in the small intestine and penetrate the intestinal wall. The larvae can travel to the brain, muscles, eyes, and skin. Neurocysticercosis, caused by Taenia solium larvae, differs from taeniasis, which results from adult tapeworm infection.

Neurocysticercosis manifests with various signs and symptoms, influenced by the location, number of lesions, and immune response. While some people may have no symptoms, others may experience seizures, increased pressure in the skull, cognitive impairment, or specific neurological problems. In severe cases, the condition can be life-threatening.

In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". Prominent examples include celiac disease, diabetes mellitus type 1, Henoch–Schönlein purpura, systemic lupus erythematosus, Sjögren syndrome, eosinophilic granulomatosis with polyangiitis, Hashimoto's thyroiditis, Graves' disease, idiopathic thrombocytopenic purpura, Addison's disease, rheumatoid arthritis, ankylosing spondylitis, polymyositis, dermatomyositis, and multiple sclerosis. Autoimmune diseases are very often treated with steroids.

Autoimmunity means presence of antibodies or T cells that react with self-protein and is present in all individuals, even in normal health state. It causes autoimmune diseases if self-reactivity can lead to tissue damage.