THE USE OF PRECIPITIN ANALYSIS IN AGAR FOR THE STUDY OF HUMAN STREPTOCOCCAL INFECTIONS

Abstract

Studies have been carried out on the purification of extracellular antigens of group A streptococcus as detected by agar precipitin analysis with human gamma globulin. At least 12 distinct antigens were produced by one strain of streptococcus. The detection of these components with human antibody imply their production in vivo during human infections. By the combined use of continuous flow electrophoresis on paper curtains and column chromatography with calcium phosphate gels, 5 of the components thus detected have been isolated in a probable high state of purity. Three of the purified antigens have been tentatively identified as streptolysin "O", diphosphopyridinenucleotidase and proteinase precursor. The latter could be very readily crystallized and appears identical with that described by Elliott. The DPNAse was of extremely high potency, 1 mg being capable of destroying 12.6 g of DPN in 7.5 minutes at 37[degree]C. The identity of the remaining 2 are uncertain, but they are distinct from each other and the above, and are not related to the C carbohydrate immunologically. One of these latter fractions showed extremely high desoxyribonuclease activity, 1 to 1.5 mg being capable of depolymerizing 400 g of calf thymus DNA in 30 minutes at 37[degree]C. Crystalline bovine pancreatic DNAse requires 4 mg for the same quantity of DNAse activity. This fraction is now thought to be DNAse B. The value of this approach in the study of the microbial products involved in the pathogenesis of infectious diseases generally was pointed out.