A Study of the Mechanism of Human Isohemagglutination

The mechanism of isohemagglutination has been interpreted in different ways by the various investigators of this phenomenon. The assumption of differences of affinity as explanatory of the purely chemical nature of such antigen-antibody reactions, as Ehrlich hypothecated, has given way to the widely accepted principle that these bodies are of colloid nature and their interactions analogous to those of colloids in general. On the other hand, Gay (1) has offered the explanation that these reactions are governed by physicochemical laws; but this conception has not been supported by sufficiently convincing proof to warrant its acceptance. Bordet (2) showed that bacterial agglutinins can be absorbed and specific agglutinins isolated by this method. The absorption of hemagglutinins was demonstrated by Malkoff (3), and later by Hektoen (4); since then, this has been observed repeatedly by others. Shibayama (5) and Ottenberg (6) showed that agglutinable cells will absorb more agglutinin than is necessary to agglutinate them, and the latter demonstrated this quantitatively by showing that one volume of agglutinable cells will absorb all the agglutinin from 16 volumes of agglutinative serum, whereas complete agglutination occurred with 13 volumes of serum. He also pointed out that when the ratio of serum to cells is 4 volumes to 6 volumes all the agglutinin is absorbed without producing agglutination, the explanation being that each of the cells absorbed some agglutinin but not enough to bring about clumping.