Precipitin reaction

By 1945, Stacey speculated about the possibility of a structural relationship between Pneumococcus capsular polysaccharides and those produced by other organisms. With Miss Schliichterer, he had examined the capsular polysaccharide of Rhizobium radicicolum. This polysaccharide gave a precipitin reaction in high dilution, not only with Type III Pneumococcus antiserum, but also mixed with antisera from other Pneumococcus types. The chemical evidence indicated that the polysaccharide resembled the specific polysaccharides of Types I and II Pneumococcus. A decade later, the acidic capsular polysaccharide from Azoto-bacter chroococcum, a soil organism, was studied. It, too, produced serological cross-reactions with certain pneumococcal specific antisera. Although the molecular structure of the polysaccharide was not established, adequate evidence was accumulated to show a structural relationship to Type III Pneumococcus-specific polysaccharide. This was sufficiently close to account for the Type III serological cross-relationship. 

Sugg and Hehre43 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 anti-Leuconostoc sera, but also pneumococcus Types II, XII and XX antisera. Leuconostoc organisms cultured on D-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,... 

It was noted in previous reviews (1,3) that injection of urease into rabbits elicited an antibody and that the precipitate formed between urease and its antibody still possessed catalytic activity. This indicates that the antigenic and catalytic regions are not identical. A more recent study employing horse and rat antisera (66) revealed only one major antigenic component in urease preparations and confirmed the lack of complete enzyme inhibition by the precipitin reaction. 

The binding equilibrium expressed as shown above (2.2) is actually a gross oversimplification of the situation. The heterogeneity of the binding sites and multiple valency of individual antibodies lead to formation of secondary bonds that contribute to hysteresis or ripening of the antibody-antigen complex. Its ultimate form is the polymerization of a primary complex, which happens when the antigen is also polyvalent. Formation of the polymer (precipitin reaction) renders such a reaction virtually irreversible. 

Application of 125I Radioimmunoassay to Measure Inhibition of Precipitin Reactions using Carbohydrate-Specific Antibodies, P. H. Boullanger, A. Nagpurkar, A. A. Noujaim, and R. U. Lemieux, Can. J. Biochem., 56 (1978) 1102-1108. 

A7. Agnello, V., Winchester, R. J., and Kunkel, H. G., Precipitin reactions of the Clq component of complement with aggregated y-globulin and immune complexes in gel diffusion. Immunology 19, 909-919 (1970). 

Precipitin Reactions Free soluble antigen in excess of antibody Free antibody Precipitin complex deposited in vascular epithelium... 

Fig. (47). The identification of gum polysaccharides used as additives in processed foods and beverages by use of precipitin reaction with specific antibodies.

Hektoen, L. and A.G. Cole The proteins of egg white. The proteins in egg white and their relationship to the blood proteins of the domestic fowl as determined by the precipitin reaction. J. Infect. Diseases 42, 1 (1928). 

Diffusion in agar performed by the conventional method shows a strong reaction between the antibody and Man-BSA, but not with BSA (Fig. 12, plates A). However, both compounds give precipitin complex with anti-BSA serum. Oxidation of the antigens with periodate no longer gives a precipitin reaction with the anti-mannose antibodies, but has no effect on the anti-BSA antibodies. Hapten-inhibition results are also shown in Fig. 12, plates C and D. These tests are conducted with the purified antibody... 

Quantitative precipitin tests were performed as described.73 The amounts of precipitates obtained at the various concentrations were measured by the protein phenol method.74 The inhibition values are recorded in Table I. These inhibition data show that the precipitin reaction between the tetrahet-eropolysaccharide and the anti-GlcA antibodies is strongly inhibited by d-glucuronic acid, but with the exception of galacturonic acid none of the other carbohydrates were inhibitory. The data in the table also show that the carbohydrates tested did not inhibit the precipitin reaction between the polysaccharide and anti-GlcA-Rha antibodies. The monosaccharides alone cannot completely fit the active site of this antibody to give a precipitin test. 

Inhibition of the Precipitin Reaction of the Tetraheteroglycan and Rabbit Antiserum... 

Percent Inhibition of Glucosyl Compounds for the Myeloma Protein and Precipitin Reaction... 

Ions of Mn2+ and Ca2+ were bound to the purified, lima-bean lectins.151,199 Removal of Mn2+ lowered the hemagglutination titer by 75%. (Ethylenedinitrilo)tetraacetate completely inhibited the precipitin reaction between lima-bean lectin component III and type A blood-group substance (compare Ref. 579). Several divalent-metal cations restored activity to the demetallized protein or (ethylenedinitrilo)tetraacetate-treated lectin the addition of Ca2+,... 

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