Bacteria antibodies

As discussed in the introduction to Section IV, the enzyme-Zinked Zmmunarorbent assay (ELISA) has become a widely used and powerful technique in the field of medical diagnostics. If an individual has been exposed to a pathogenic organism (virus, bacteria), antibodies that recognize particular antigens specific to these organisms will be present in the blood plasma. Because of this, a blood test can often reveal the source of an infection and dictate a proper course of treatment. 

Since immunoassays utilize antibodies as analytical reagents, the challenge is to obtain antibodies specific for an individual compound that may be present in a milieu of structurally related and unrelated compounds. Antibodies can be produced by in vivo immunization (polyclonal antibodies), hybridoma technology (monoclonal antibodies) and by genetically engineered bacteria (antibody fragments with affinities for specific molecules). Some caveats pertaining to the production and use of such antibodies in immunoassay procedures will be presented. 

The barcodes have been primarily used to assure brand and authenticity in pharmaceuticals, but applications could be forthcoming in tracing food batches. Combined with pathogen sensors, the barcodes that must be read by modified microscopes could trace sources of outbreak. There are antibacterial surfaces for the machines involved in food processing or production. With the conventional methods of detection it takes hours to days. With molecular electronic based methods, biosensors, e-nose, microarrays, nanobiosensors (based on microfluidic, nanomaterials, DNA, etc.) it takes seconds to minutes. A biosensor developed by an Agricultural Research Service scientist, Athens, uses fluorescent dye particles attached to bacteria antibodies. If Salmonella bacteria are present in the food being tested, the nanoculturing results with these two examples of instantaneous sensors, sized dye particles become visible. No need to send out to the lab and wait days for results. 

Latex agglutination immunoassays are easily formatted into simple kits which can provide yes/no and semiquantitative estimates of antigen (or antibody) in a sample. The first such assay was developed in 1957 for rheumatoid factor (15) and assays are on the market for the deterrnination of many species of bacteria, fungi. Mycoplasma, parasites, ckettsia, and vimses, as well as for the deterrnination of autoimmune disease, hormones (qv), dmgs (see Pharmaceuticals), and blood proteins (16). Latex agglutination is also the basis of many home pregnancy tests. 

Antibodies secreted by B cells bind to foreign material (antigen) and serve as tags or identifiers for such material. Antibody-tagged bacteria. 

In general, diagnostic tests that look for a particular protein of interest use biologically derived antibodies, usually from mice. However, proteins, DNA, RNA, and other biologicals may be derived from a variety of organisms like bacteria, yeast, plants, and other mammals for use as diagnostics. 

Humoral immunity depends on soluble, noncellular effector mechanisms of the immune system. These include defensins and complement components (proteins of the innate immune system) and antibodies (products of the adaptive immune system). They are capable of reacting with foreign substances (e.g., bacteria and viruses) to produce detoxification and elimination. 

A toxin is a poisonous substance produced by some bacteria, such as Clostridium tetani, the bacteria that cause tetanus. A toxin is capable of stimulating the body to produce antitoxins, which are substances that act in the same manner as antibodies. Toxins are powerful substances, and like other antigens, they can be attenuated. A toxin that is attenuated (or weakened) but still capable of stimulating the formation of antitoxins is called a toxoid. 

IgG Main antibody in the secondary response. Opsonizes bacteria, making them easier to phagocytose. Fixes complement, which enhances bacterial killing. Neutralizes bacterial toxins and viruses. Crosses the placenta. 

Immunologic abnormahties (eg, transfusion reactions, the presence in plasma of warm and cold antibodies that lyse red blood cells, and unusual sensitivity to complement) also fall in this class, as do toxins released by various infectious agents, such as certain bacteria (eg, Clostridium). Some snakes release venoms that act to lyse the red cell membrane (eg, via the action of phospholipases or proteinases). 

The process of activation of neutrophils is essentially similar. They are activated, via specific receptors, by interaction with bacteria, binding of chemotactic factors, or antibody-antigen complexes. The resultant rise in intracellular Ca affects many processes in neutrophils, such as assembly of micrombules and the actin-myosin system. These processes are respectively involved in secretion of contents of granules and in motility, which enables neutrophils to seek out the invaders. The activated neutrophils are now ready to destroy the invaders by mechanisms that include production of active derivatives of oxygen. 

Fever is the most common manifestation. The thermoregulatory centre in the hypothalamus regulates body temperature and this can be affected by endotoxins (heat-stable lipopolysaccharides) of Gram-negative bacteria and also by a monokine secreted by monocytes and macrophages called interleukin-1 (IL-1) which is also termed endogenous pyrogen. Antibody production and T-cell proliferation have been shown to be enhanced at elevated body temperatures and thus are beneficial effects of fever. 

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