Using a highly concentrated and partially purified streptolysin O preparation, migrating agar precipitins have been found in 94 of 143 human sera from patients with a variety of diseases. Most of those showing no bands, had very low antistreptolysin titers.
A correlation was found between the migration rates of these bands and the antistreptolysin titer. A strong trend toward a straight line relationship was apparent when the ASO titers were plotted on a logarithmic scale. In addition, a roughly positive correlation was found between the intensity of these bands and the antistreptolysin O titers. The finding of high levels of antistreptolysin O activity and slowly migrating heavy bands in normal pooled human gamma globulin supported the above observations.
Very similar results were obtained with rabbit and guinea pig sera after immunization with the streptolysin O concentrates.
The data strongly indicate that antistreptolysin O activity in human sera is generally due to precipitating antibody, and that non-specific inhibitors are not usually involved, even with low titered sera.
Rabbit and guinea pig antisera to the oxidized inactive and to the reduced active forms of streptolysin O showed no obvious differences. Attempts to demonstrate immunological differences between the two states of streptolysin were apparently complicated by proteolysis, due to contamination of the concentrates with proteinase precursor.