抄録
The, common conception of precipitative and agglutinative reactions is that they proceed in two phases. This conception was offered by Bordet (1899) for the first time.In the first phase the antigen unites specifically with the antibody and becomes coated with this specifically combined “antibody-globulin”. As a consequence of this union the surface of the antigen-antibody compound is hydrophobe and sensitive to the flocculating effect of electrolytes, of a kind and in a concentration to which uncombined antigen or antibody is indifferent. It is commonly held that the most important effect of electrolytes is to lower the surface charge of the primary antigen-antibody particlesi and so to allow their aggregation into particles of increasing size. This is the second phase of precipitation or agglutination. It is commonly regarded, in contrast to the first phase, as being nonspecific, the primary antigen-antibody particles behaving as a salt-sensitive colloidal suspension.
In his recent stimulating monograph on the chemistry of antigens and antibodies, Marrack (1934) has speculatively offered an alternative hypothesis. It supposes a continuous physico-chemical reaction in which the aggregates are built up of particles of antigen and antibody specifically linked together to form a Lattice structure in a manner analogous to the formation of crystals.
Heidelberger and his colleagues supported Marrack's theory in the quantitative studies on immune serum precipitation and agglutination. Pauling (1940) adopted the Marrack's hypothesis in his recent theory of the structure and process of formation of antibodies.
These authors supported Marrack's theory on the indirect basis. On the other hand many authors have appeared who have studied experimentally on this problem. There are two kinds among these experiments.
From the Marrack's hypothesis it would follow that only antigenically related particles and their corresponding antibodies can enter into the formation of common aggregates; and when suspensions of antigenically unrelated particles sensitized with their homologous antisera are mixed together, the different kinds of particles will not combine to form heterogeneous aggregates, as supposed in the Bordet's theory, but each kind will independently form its own homogeneous aggregates.
Topley, Wilson, and Duncan (1935) were the first to suggest studies on mixed agglutination of morphologically distinguishable antigens as a method of solving this problem, and they obtained the results supporting the Marrack's hypothesis. Wiener and Herman (1939), and Umezawa (1942) have also supported the Marrack's hypothesis from the results of such experiments, but Abramson (1935), and Hooker and Boyd (1937) have supported the Bordet theory.
In the second kind of experiments compared the times taken for a particular stage of agglutination or precipitation, observed macroscopically, in a mixture of two antigenically different agglutinating or precipitating systems, reacting synchronously, and in independent controls of each of these systems diluted to give a concentration equal to that of the same system in the mixture. As the velocity of. agglutination and precipitation depends upon the incidence of effective cone tcts between the agglutinable particles, it follows that according to the Bordet Fiypothesis the velocity of flocculation will be proportionate to the total concentration of particles and will be much greater in the mixture than in the independent system controls in which the concentration of agglutinable particles, following dilution, will be only half the total of the mixture; but if the two systems in the mixture react independently as supposed in the Mariack, hypothesis, the comparable concentrations of the agglutinating systems in the mixture and in the controls will be equal, and agglutination in the mixture will not show acceleration.
