Hapten haptens

Carrier Molecule Hapten Hapten-carrier Immunogen... 

Antigens not only induce an immune response, but will also react with antibodies existing in a living organism. These two properties are different. Small molecules like pesticides are not able to induce the production of antibodies. They can only react with antibodies already present. They are called haptens. To generate antibodies specific to a hapten, haptens must be covalently bonded to a protein (e.g. BSA Bovine Serum Albumin) or polysaccharide. Therefore, the hapten must have reactive sites. On the other hand, this modification in the structure must not influence the specificity of the antibodies that will be produced. 

The exact mode of binding to Fab fragments has been established for several specific haptens. Haptens are small molecules having the binding properties... 

Haptens.—Haptens have been prepared from steroid hormones by reactions at C-3 or C-17, or in the pregnane side-chain. Antibody specificity is often improved, however, by anchoring the steroid through a middle-ring site to the protein, so that both ends of the steroid component of the complex are exposed for recognition in the antibody-forming process. 

Fig. 2 Hapten/peptide and p-i concept of T cell stimulations by drugs, (a) Haptens haptens are chemically reactive compounds. Drugs like penicillin are haptens they bind to lysine amino acids in proteins or by the SH-group formed by opening the thiazolidine ring. This covalent binding can modify soluble or cell bound molecules. They can even bind directly to the immunogenic major histocompatibiliy complex (MHC)/peptide complex on antigen presenting cells (ARC), either to the embedded peptide or to the MHC molecule itself. Thus, the chemical reactivity of haptens can lead to...

Immunoassays for small organic compounds usually are formatted as competition assays (13.141. There are many assay formats and choices of label for the eventual quantification of binding. An equilibrium is approached for formatirxi of complexes between the antibody, labeled or immobilized hapten (hapten ), and fiee analyte in the sample, according to the following equation. 

As a low molecular weight compound DAS is not significantly immunogenic, ie, it is a hapten and thus requires conjugation to a suitable antigenic carrier in order to eUcit a successfiil antibody response in animals. DAS treated with succinic anhydride results in the D AS—hemisuccinate (DAS—HMS) shown. 

The antigen-binding site binds haptens in crevices and protein antigens on large flat surfaces... 

Haptens, a special class of antigen, are small molecules that induce specific antibody production when they are attached to a protein that acts as a carrier. Phosphorylcholine is one such hapten that has been widely used in the investigation of immune responses. The specific binding of this hapten... 

The shape of the interaction area between lysozyme and the CDR loops of the antibody is easily distinguished from the hapten-binding crevice. The interaction extends over a large area with maximum dimensions of about 20 X 30 A (Figure 15.15). The interaction surface is irregular but relatively flat, with small protuberances and depressions that are complementary in the antigen and the antibody. Residues from all six CDR loops contribute to the... 

IQ was derived using propylenediamine to the appropriate propylamino derivative and acylated with 4-nitrobenzoyl chloride to nitrobenzamides 105 the ni-trobenzamides were used as haptens to generate the anti-IQ specific monoclonal antibodies (87H2069). 

Immobilization of A and B blood group oligosaccharide haptens and preparation of immunoadsorbents with specificity to anti-A and anti-B antibodies has been carried out with the use of poly acrylate-coated PG (WPG-PA) [124]. Prespacered A and B-trisaccharide-fl-aminopropylglycosides were used for the synthesis. WPG-PA (1 g) quantitatively binds both haptens (2 pinole) whereas some other activated affinity supports (for example, CNBr-Sepharose 4B) do not. On the other hand, glycidoxypropyl-silica binds prespacered haptens completely but these materials reveal no specific adsorptivity. 

The reaction product 136 is not an appropriate hapten for generating catalytic antibody as it does not closely resemble the reaction intermediate 135. Antibody 1E9 was prepared against hapten 137, a stable analog of 135, and the catalyst promoted the Diels-Alder reaction with multiple (> 50) turnovers. 

Keywords stable analogs of transition state are used as haptens to elicit antibodies that will catalyze Diels-Alder reaction... 

Fig. 21 Cationic P( VI) hapten for biomimetic photo synthetic studies...

RCM are not able to form haptens Positive skin tests in patients but not in controls in optimal concentrations... 

An argument against an immunologic reaction in non-immediate hypersensitivity reactions has been the lack of a hapten. Non-ionic RCM are chemically non-reactive... 

Second, the reactive species of a xenobiotic may bind to a protein, altering its antigenicity. The xenobiotic is said to act as a hapten, ie, a small molecule that by itself does not stimulate antibody synthesis but will combine with antibody once formed. The resulting antibodies can then damage the cell by several immunologic mechanisms that grossly perturb normal cellular biochemical processes. 

Davio et al. (43) report efforts to obtain monoclonal antibodies (mAbs) to STX. Because STX is a small molecule of approximately 300 daltons, well below the size necessary for immunogenicity, a carrier molecule must be conjugated to the hapten (STX). This technique must minimize alterations of the antigenic form. For the anti-STX antibodies tested to date, the ratios of immunoassay response factor to pharmacological potency for various STX derivatives differ substantially, the immunoassay being virtually unresponsive to some of the common natural derivatives (44). 

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