Anaphylaxis in mice with fragments of rabbit antibody

AT present there is much interest in the relationship between the sensitizing capacity of antibodies and their affinity for tissues. Ovary and Karush¹ found that univalent fractions I and II (FI, FII) obtained from purified rabbit anti-haptene antibody by papain digestion were unable to sensitize the guinea pig for direct passive cutaneous anaphylaxis (PGA) or reversed PCA. They postulated that the site necessary for the fixation of antibody to guinea pig tissues was not present on fractions I and II but was carried by fraction III. Reversed PCA could be produced with F III and horse anti-rabbit globulin. Ishizaka et al.² stated that pepsin-digested rabbit globulin, which presumably lacks fraction III, would not induce inflammatory reactions in guinea pig skin and would not fix complement. Taranta and Franklin³ also found that pepsin-digested antibody did not fix guinea pig complement in vitro. It seemed of interest to us to test papain and pepsin digesteo fragments of rabbit γ-globulin in a system in which tissue fixation of antibody does not seem to play a part, namely, anaphylaxis in the mouse. In this species maximal incidence of anaphylaxis with rabbit antibody can be obtained by injecting antibody and antigen intravenously in rapid succession⁴.