The problem of detection of tissue antigens

Summary Utilization of the anaphylactic reaction for distinguishing tumor antigens from antigens of normal tissues requires the preliminary investigation of 2 problems: 1) how should desensitization against major antigens be performed in order to be sure of its completeness, and 2) how does such desensitization affect the sensitivity of the animal to minor antigens? Experiments were carried out on guinea pigs which were sensitized by mixtures of two antigens (foreign serums, tissue nucleoproteins) mixed in different proportions. It was demonstrated that the desensitizing dose of a major antigen is several times as great as the shocking dose, and therefore that repeated injection is necessary to bring about complete desensitization. This causes a pronounced decrease of the sensitivity to the minor antigen. Therefore it is necessary to increase the dose of the preparation containing the mixture of antigens (for example, a tumor extract) in order to obtain a definite anaphylatic reaction. These findings should be taken into consideration in employing anaphylaxis for the demonstration of antigenic differences between tumors and normal tissues.