Light-scattering Studies of the Formation of Aggregates in Mixtures of Antigen and Antibody.

Formation of aggregates in mixtures of antigen and antibody was followed by measurement of the intensity of light scattered at 90° and of the ratio of the intensities of light scattered at 45° and 135° under varied environmental conditions—concentration, antigen/antibody ratio, temperature, concentration of neutral salts, hydrogen ion and organic solutes. We propose that the aggregation of antigen-antibody complexes is accelerated by change in the structure of antibody molecules that occurs on combination with antigen. The effect of solutes on the rate of aggregation may be due to reduction of the association constant of the combination of antigen and antibody or to inhibition of the change in structure of antibody on combination. Acceleration of the early stage of aggregation by increase of temperature is attributed to increased rate of change in the structure of antibody. [ABSTRACT FROM AUTHOR]