A Study of the Inhibition of Streptococcal Proteinase by Sera of Normal and Immune Animals and of Patients Infected with Group A Hemolytic Streptococci.

The research involves investigation of the inhibition of the streptococcal proteinase enzyme by the sera of healthy and immune animals, as well as patients infected with group A hemolytic streptococci bacteria. It was discovered that the sera’s antiproteinase activity is linked to the action of specific antibodies against the streptococcal proteinase. Also, no correlation between occurrence of rheumatic fever and the antiproteinase titre of the patient’s serum was found.

Research Methodology and Results

• The study conducted involved preparing antiproteinase sera by immunizing horses with filtrates derived from a specific strain of group A streptococcus. This strain was chosen from 42 different strains for its distinctive characteristic of producing a high amount of proteinase but no erythrogenic toxin.
• In addition to this, a handful of strains from groups B, C, and G were tested. However, these groups were found to be devoid of any proteinase activity.
• A methodology was set and described for titrating streptococcal proteinase in crude culture filtrates and for estimating the antiproteinase activity of serum.
• The investigation found that the antiproteinase titers of the immunized horse sera ranged from 125 units to 1,000 units per cubic centimeter. Regular horse sera, on the other hand, displayed comparatively low titers, with just 5% having titers as high as 10 to 30 units per cubic centimeter.
• The evidence that was collected suggests that antiproteinase activity in immune sera depends on the reaction of a specific antibody against streptococcal proteinase.

Relation to Rheumatic Fever

• Additionally, the study investigated the relationship between antiproteinase titers and the incidence of rheumatic fever in patients infected with Group A streptococci.
• It was observed that patients with this infection did not show high antiproteinase titers.
• Moreover, no correlation was found between the existence of rheumatic fever and the antiproteinase titre aspect ratio of the patient’s serum.

In conclusion, this research demonstrates the inhibitory action of antiproteinase sera on streptococcal proteinase, with potential implications for understanding the body’s immune response to Group A streptococcal infections.