Quantitative studies on anaphylaxis in vitro II. Studies on the species difference of diphtheria antitoxin in sensitizing activity

Inability of antisera of certain animal species to sensitize individuals of other species passively has been reported by numerous investigators (Follensby et al., 1944; Kabat et al., 1944). For example, rabbit diphtheria antitoxin as well as guinea pig antitoxin passively sensitize guinea pigs, whereas horse antitoxin fails to induce passive sensitization (Neill et al., 1922). But the reason of such species difference in the sensitizing power of various antisera is obscure. In the previous study, using diphtheria antitoxin, it was proved that the degree of sensitization is determined by the concentration of tissue antitoxin (Ishizaka et al., 1956). Therefore, if the tissue antibody concentration should have concern with the species difference of the antiserum used for 'se'nsitization, the degree of sensitization would depend on the antiserum used. Thus, in the present report, it was examined whether or not the concentration of tissue antitoxin, which is reactive to the antigen added, is different depending on the species of antitoxin. Moreover, by the application of the experimental procedure described in the previous report, the influence of non-sensitizing antibody in the tissues on the degree of sensitization was studied.