Specific antibody source

Species origin tests, used to determine whether the specimen is human or from another source, are immunological in nature. Host animals, usually rabbits, are injected with protein from another species. The animal creates antibodies to the unknown material. Semm from the host animal, containing species (human, bovine, equine, canine, etc) specific antibodies, is tested against a dilute solution of blood (antigens) collected as evidence. A positive reaction is determined by a visible band where the antibodies and antigens come into contact. 

Recently, SETA BioMedicals has developed a new near-infrared squaraine-based label Seta-633, which can be used to study the interaction between low-molecular-weight analytes and proteins using fluorescence lifetime as the readout parameter [19]. This label exhibits lower quantum yields and shorter fluorescence lifetimes when free in solution, but these values substantially increase upon interaction with proteins, which is contrary to tracers like Cy5 or Alexa 647. It was demonstrated in a model assay that a biotinylated Seta-633 binds to anti-biotin with high specificity. Importantly, the lifetime of Seta-633-biotin increases about 2.76 fold upon binding to a specific antibody (anti-biotin, MW =160 kDa), while the titration with BSA or nonspecific antibody does not result in a noticeable change in lifetime (Fig. 13). The label is compatible with readily available light sources (635 nm or 640 nm lasers) and filter sets (as for Cy5 or Alexa 647) and its... 

Table 4.1 Quantity of specific antibodies from various sources (adapted from the Roche Molecu lar Biochemicals pamphlet Lab FAQS )...

Source Type Quantity of total antibody Quantity of specific antibody Contaminating antibodies Purity of specific antibody... 

Since many interferences with diethylstilbestrol analysis are caused by undefined sources, use of a highly specific antibody would probably not correct the problem. Nevertheless, several attempts to prepare a drug-specific antibody have been made without success. Thus, more emphasis was finally placed on developing more efficient extraction and cleanup procedures to ensure selectivity. Current methods combine several cleanup steps based on different isolation principles to provide adequately purified sample extracts for the determination of diethystilbes-trol by radioimmunoassays (Table 28.4). 

Immunosuppressant antibodies continue to gain acceptance as a method for preventing rejection of transplanted tissues and for treating various autoimmune diseases.17,47 For more information on the use of specific antibodies in specific disorders, please refer to other sources on this topic.17,41,47,56... 

Amplified DNA is identified by solution hybridization of two nonisotopically labeled oligonucleotides to one strand of the amplified DNA. Following hybrid formation DNA is bound to a solid phase and detected by enzyme-labeled specific antibodies. Because only one strand is used for detection, the other one is washed off and constitutes the main source of laboratory contamination and carryover. Take precautions to avoid the spread of these molecules to other rooms (e.g., work in a chemical fume hood, decontaminate used wash buffer with acid or sodium hypochloride, and so on). 

Antigen-specific antibodies produced by B-cells are secreted and appear in the blood serum of an immunized animal, from where they can be isolated as polyclonal mixtures, usually from rabbits. Alternatively, isolation of B-cells from the spleen of an immunized mouse and fusion with myeloma (tumor cells) yields hybridoma , which are antibody-producing cells that can be propagated in vitro [4]. Each hybridoma cell line secreting an antigen-specific antibody can be isolated and provides a source of a single monoclonal antibody. Polyclonal and monoclonal antibodies to a variety of proteins are commercially available, and many industrial and academic laboratories offer to produce polyclonal or monoclonal antibodies. 

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