Experimental nephritis due to type specific streptococci. VI. Further characterization of type 12 nephrotoxin

Abstract

Additional studies were undertaken on the nature of a nephrotoxic agent found in the culture filtrates of certain group A streptococci. A commercially available dehydrated medium proved satisfactory for the production of the active material. Gel filtration was used to divide polypeptide extracts, prepared from the dialyzable portion of culture filtrates, into two major fractions. One of these, representing the higher molecular weight components, contained most of the nephrotoxic activity as evidenced by the development of hypertension and acute glomerulonephritis in rabbits injected with this fraction.Physical and chemical studies indicated that the active fraction consisted of at least four polypeptide components separable by high voltage electrophoresis on paper. Automatic amino acid analysis of an acid hydrolysate of this fraction revealed 17 different amino acids. Carbohydrate was not detected by anthrone and orcinol tests.No relationship was established between this streptococcal nephrotoxic agent and other streptococcal constituents which have been implicated in acute glomerulonephritis.