The Relationship of Circulating Antibody to the Local Inflammatory Reaction to Antigen (the Arthus Phenomenon)

Abstract

Summary The results shown in this paper indicate that the presence of circulating precipitin is necessary for local inflammatory reactions of the type described by Arthus. The severity of the Arthus reaction in the skin is directly correlated with the amount of antibody in the blood. When the circulating precipitin disappears with time or is eliminated by an intravenous injection of antigen from an actively sensitized animal known to be capable of giving an Arthus reaction, that animal is no longer sensitive to the skin test. The injection of an amount of antigen just sufficient to remove all the circulating antibody results immediately in the loss of skin sensitivity. All of the evidence obtained indicates that tissue hypersensitiveness in an actively sensitized animal is dependent upon the formation of antibody by the animal and is reflected by the presence of precipitin in the circulation. The importance of antibody in the Arthus test is further brought out in the experiments upon passive transfer of hypersensitiveness. When the precipitin is absorbed from an antiserum, that antiserum loses its power to sensitize passively a normal animal. Such a serum is also unable to elicit a reaction on injection into the skin of a normal animal which has been injected intravenously with the specific antigen. The tissue sensitizing substance in an antiserum appears to be inseparable from and, probably, identical with the precipitin. Several of these observations are contrary to those reported by Kahn in his numerous publications upon the subject and cast doubt upon the conclusions to which Kahn has been led. The existence in the skin or other organs of any sensitizing agency other than the antibody appears not to be essential for an explanation of the mechanism of the Arthus reaction. Such an agency has, furthermore, thus far not been demonstrated. The data here offered supports entirely the contention of Opie that the union of antibody with antigen is responsible for the Arthus reaction.