Serological Reactions With Simple Chemical Compounds (Precipitin Reactions)

Abstract

Serological reactions with chemical compounds of simple constitution were demonstrated for the first time by means of the so called inhibition reaction (1,2). This subject has been discussed (1), and the arguments given for the view that the inhibition phenomena are caused by a combination of the inhibiting substances with antibodies, thereby preventing their precipitating action. Although there is no reasonable doubt as to the validity of this explanation which is strongly supported by the close similarity in the specificity of inhibition and precipitin reactions and the analogy to the inhibition produced by an excess of precipitable substances, it has remained of value to furnish direct experimental proof of the combination of antibodies with low molecular compounds by a reaction which does not involve the use of protein antigens.In experiments on anaphylaxis to azoproteins it was shown that previous injection with azodyes protected sensitized guinea pigs against the shocking action of azoproteins containing the same azo component (3-5). Since this protection was still evident after the dyes had practically disappeared from the circulation, the effect was attributed to a neutralization of antibodies. In some cases the injection of the dyes was even followed by typical anaphylactic symptoms. Klopstock and Selter (6) reported that they obtained complement fixation reactions with immune sera to azoproteins, and emulsions of lecithin preparations to which had been added diazotized p-arsanilic acid or metanilic acid. Interesting experiments were carried out by Marrack and Smith (7) who were able to show that the diffusion of an azodye prepared from p-arsanilic acid is interfered with by the addition of an immune serum specific for the azo component.Attempts made in the course of studies on azoproteins to produce specific precipitin reactions with simple azodyes did not lead to consistent results. Recently, a special group of azodyes was found with

Studies on Artificial Antigens

“…Arsanilic acid conjugates (AS) of these preparations were made by diazotization (14). The number of arsanill c acid groups in the conjugates was estimated from the optical density of the preparations at 330 m/~ using as reference the absorption coefficient of chloracetyltyrosine azo arsanilic acid at that wave length.…”

The Precipitin Reaction Between Type Iii Pneumococcus Polysaccharide and Homologous Antibody

“…However, with the specific grouping repeated two or more times, as in azo dyes studied by Landsteiner and van der Scheer s The combination of the polysaccharide S I I I with the antibody would increase the number of "hydrophilic groups" on the molecule rather than decrease them, so that Eagle's explanation for the insolubility of the precipitate would not be applicable (24). (25), compounds of the type AH. AH .…”

A compact vocabulary of paratope-epitope interactions enables predictability of antibody-antigen binding

“…The hypervariability of the CDR3 is key to the immunological specificity of antibodies (Xu and Davis, 2000) and is generated by somatic recombination of the variable (V), diversity (D, only for the heavy chain), and joining (J) genes of the B-cell genomic locus (Tonegawa, 1983). Combinatorial diversity from rearranged germline gene segments, somatic hypermutation, and antigen-driven selection steps enable antibodies to interact specifically with virtually any given antigen (Landsteiner, 1936;Padlan, 1977;Tonegawa, 1983).…”