Studies on the “Toxins” of Hemolytic Streptococci

Abstract

Summary For the test of the toxicity of anatoxin strongly Dick-positive reactors of younger ages or white pigs must be preferred, as they react only slightly, or do not react at all to nucleoproteins contained in the anatoxin. There is no practical method for the determination of the immunizing value of anatoxins. It must, therefore, be determined by the practical effect of preventive immunization. Concentration of anatoxin by means of two volumes of absolute alcohol in a normal salt solution containing 0.5 per cent phenol is the most convenient for the use of anatoxin, since this method not only eliminates formalin, but also diminishes substances other than toxin or toxoid which may be considered as a causal agent for the discomforts caused by the inoculation, and also since the dose of injection may be reduced to a great extent. The use of an anatoxin of moderate toxicity is more suitable, because the decrease in antigenicity follows more or less that in toxicity and the discomforts caused by inoculation of anatoxin may depend no less upon the protein substances contained in the anatoxin than upon the retained toxicity of the essential toxin itself. To reduce the toxicity to 1/1000th of its original toxicity, the action of 2 per cent formalin at 37°C. for thirty days, 1 per cent formalin at 45°C. for thirty days, or 2 per cent formalin at 45°C. for ten days are sufficient. The reduction of toxicity to 1/200 or 1/300th of its original toxicity could be brought out either by the action of 1 per cent formalin at 37°C. for thirty days, or 1 per cent formalin at 45°C. for ten days, or 0.5 per cent formalin at 45°C. for thirty days. The immunizing value of an anatoxin detoxified to 1/1000th of its original toxicity is only slight, whereas about 80 per cent of the children (five to thirteen years) had been successfully immunized by three injections (0.5, 1.0 and 1.5 cc.) of the anatoxins detoxified to 1/200th or 1/300th of their original toxicity. A 20-fold concentrated solution of an anatoxin prepared by dissolving precipitates caused by the addition of 2 volumes alcohol in normal saline solution containing 0.5 per cent phenol could be kept at least for three months without loss of its antigenic properties if kept in an ice box.