Reactions induced by intracutaneous injections of toxins of streptococci from scarlet fever.

Abstract

With toxins prepared in this laboratory from a strain of a scarlet fever streptococcus received from Doctor Dochez, no skin reactions were induced in rats, mice, guinea-pigs, kittens, chickens, pigeons, monkeys, sheep or a calf. Questionable reactions were obtained in two young pigs with undiluted toxin and also in four rabbits out of eighteen, the remaining fourteen giving no reactions.

Definite skin reactions, however, have been induced in white goats. All fourteen goats tested gave reactions to the toxin, but individual goats appeared to vary in susceptibility. With ten, definite reactions were obtained with 0.2 cc. of a 1:500 dilution of a toxin which gives a reaction in a 1:1000 dilution in a susceptible human being. Four other goats gave reactions to lower dilutions, varying from 1:50 to 1:250. The reactions in goats reached a maximum in 18 to 24 hours and at this stage were usually quite similar to those observed in human beings. In the more susceptible goats according to the potency of the material tested, these reactions varied in degree from slightly reddish areas, 1.5-2 cm. in diameter with no swelling, to large reddish areas from 3-5 cm. in diameter with considerable swelling. All reactions, even the most severe, faded in 48 to 72 hours. With some goats, the darker color of the skin made the readings difficult.

Toxin heated for one hour at 100° C. and uninoculated broth gave no reaction nor was any obtained with toxin neutralized with scarlet fever antitoxic serum, but normal horse serum, even in low dilutions did not neutralize the toxin. Toxins from another strain of streptococcus from scarlet fever, which gave no reaction in susceptible human beings in a 1:250 dilution, also induced no reaction in goats, in the same dilution.