ANTITULARENSE SERUM: CORRELATION BETWEEN PROTECTIVE CAPACITY FOR WHITE RATS AND PRECIPITABLE ANTIBODY CONTENT

Abstract
Protective antibody was demonstrated in 2-ml. quantities of each of 4 immune serums by intraperit. injn. of the 85- to 110-g. white rat, and by immediate subcut. challenge with 25 million viable organisms of maximal virulence, an average of 25,000 LD50 rat doses. Pre-challenge treatment with normal serums gave 95% mortality. Pre-treatment with immune serums of graded potency gave mortality rates ranging from 12.5% to 48% and these were inversely proportional to the precipitable antibody contents of the serums.