Haptenes

The Wassermann substance17 is prepared by extracting various animal organs, particularly beef heart, with alcohol, and its lipidal nature was early recognized. Pangborn174 described the preparation of a new phospholipid termed cardiolipin from beef heart and claimed that it was the essential constituent of the Wassermann substance. On hydrolysis it gave a fatty acid and a phosphorylated polysaccharide. In a later communication17 however, the carbohydrate constituent is stated 

The Forssman antigens17 may be regarded as heat-stable substances, which, when injected into rabbits, can evoke sheep-cell hemolysins. 

The lipid constituents of the acid-fast bacilli, particularly the tubercle bacillus, have been extensively studied and there is good evidence that carbohydrate-lipid complexes play an important part in the sero- 

Industrial Significance of Dextran Produced by Leuconostoc Species. 217 

Sugg and Hehre also obtained precipitin reactions with dextran or with sterile filtrates of sucrose broth cultures of L. mesenteroides (designated for convenience strain A) and not only oxA -Leuconostoc sera, but also pneumococcus Types 11, XII and XX antisera. Leuconostoc organisms cultured on n-glucose broth neither stimulated the production of dextran-reactive antibodies in rabbits, nor absorbed dextran-reactive antibodies from sera, as did organisms cultured on sucrose. Absorption with the homologous bacteria Leuconostoc, pneumococcus Types II, 

XII or XX) removed the capacities of each antiserum to react with all of the antigens, and absorption with each kind of bacteria removed the capacity of all the antisera to react with antigens of that kind of bacteria. 

Dextran resulting from the action of another strain of L. mesenteroides (designated for convenience, strain B) was more soluble than strain A dextran and exhibited somewhat different immunological reactions. This strain B dextran reacted only slightly with pneumococcus Type XII antisera and had a narrower zone of antigenic reactivity than the strain A dextran. In addition, the strain A organisms exhibited a greater capacity to absorb antibodies reactive with the B dextran than did the B bacteria to absorb antibodies reactive with the A dextran. 

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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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