Animals antigenicity testing

Organ weights (spleen, thymus, all animals) Immunotoxicity tests (1) functional tests (either a splenic plaque-forming cell (PEC) assay or an Enzyme-Linked Immunosorbent Assay (ELISA) to determine the response to antigen administration) (2) enumeration of splenic or peripheral blood total B cells, total T cells, and T-cell subpopulations Detailed clinical observations Functional observations (sensory reactivity to stimuli of different types, grip strength, motor activity, more specialized tests on indication)... 

Current immunoassays make use of polyclonal or monoclonal antibodies to capture test analytes from serum or plasma samples. A limitation for all sandwich-type immunoassays occurs when the patient sample contains heterophile or human anti-animal antibodies. These antibodies occur in patients with autoimmune diseases and exposure to animal antigens, respectively. When present, these antibodies bind to both the capture and signal antitroponin antibodies, thereby producing a falsely positive signal in the absence of the analyte (Figure 92.2b). Commercial assays for cardiac troponin are not immune... 

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. 

Several soluble antigens that have been produced in plants using plant viruses as expression systems have shown immunogenic and protective properties in test animals [11]. The plant-derived proteins, which include known immunogens from pathogens or allergens from plants [38], have been tested either as crude plant extracts containing recombinant protein or as purified material from the infected plants. 

Scientists have also since demonstrated that DNA (coated on microscopic gold beads) propelled into the epidermis of test animals with a gene gun , is expressed in the animal s skin cells. Furthermore, the introduction in this fashion of DNA coding for human influenza viral antigens... 

The importance of PAF in airway hypersensitivity has been confirmed by the protective effect exerted by BN 52021 and related ginkgolides [192] in (i) PAF-induced bronchoconstriction and airway hyperreactivity in both humans and animals (ii) various models of immune anaphylaxis and airway hyperreactivity in animals and, as we shall discuss later (iii) antigen-induced bronchial provocation tests in asthmatic patients. 

Species differences must be considered when choosing a model and, in particular, species-specific immunological differences between the human and the test animal. For example, in humans, an anti-CD4 monoclonal antibody (MAb) will bind to CD4 expressed on monocytes, with subsequent fixing of complement and destruction of antigen-presenting cells. However, since CD4 molecules are not expressed on murine monocytes, these effects would not be evident in a murine model. 

The principle behind the test method(s) is that antibodies are made of proteins that recognize and bind with foreign substances (antigens) that invade host animals. Synthetic antibodies have been developed to complex with petroleum constituents. The antibodies are immobilized on the walls of a special ceU or filter membrane. Water samples are added directly to the cell, while soils must be extracted before analysis. A known amount of labeled analyte (typically, an enzyme with an affinity for the antibody) is added after the sample. The sample analytes compete with the enzyme-labeled analytes for sites on the antibodies. After equilibrium is established, the cell is washed to remove any um-eacted sample or labeled enzyme. Color development reagents that react with the labeled enzyme are added. A solution that stops color development is added at a specified time, and the optical density (color intensity) is measured. Because the coloring agent reacts with the labeled enzyme, samples with high optical density contain low concentrations of analytes. Concentration is inversely proportional to optical density. 

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